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Sample records for occult scaphoid fracture

  1. Diagnosis of Occult Scaphoid Fractures: A Cost-Effectiveness Analysis.

    PubMed

    Karl, John W; Swart, Eric; Strauch, Robert J

    2015-11-18

    Scaphoid fractures are common but may be missed on initial radiographs. Advanced imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI) have improved diagnostic accuracy, but at an increased initial cost. The purpose of this study was to evaluate the cost-effectiveness of immediate advanced imaging for suspected occult scaphoid fractures. A decision analysis model was created to evaluate three diagnostic strategies for patients with concerning history and examination but negative radiographs: (1) empiric cast immobilization with orthopaedic follow-up and repeat radiography at two weeks post-injury, (2) immediate CT scanning, or (3) immediate MRI. Prevalence of occult scaphoid fracture, sensitivity and specificity of CT and MRI, and risks and outcomes of a missed fracture were derived from published clinical trials. Costs of imaging, lost worker productivity, and surgical costs of nonunion surgery were estimated on the basis of the literature. Advanced imaging was dominant over empiric cast immobilization; advanced imaging had lower costs and its health outcomes were projected to be better than those of empiric cast immobilization. MRI was slightly more cost-effective than CT on the basis of the mean published diagnostic performance, but was highly sensitive to test performance characteristics. Advanced imaging would have to increase in cost to more than $2000 or decrease in sensitivity to <25% for CT or <32% for MRI for empiric cast immobilization to be cost-effective. Given its relatively low cost and high diagnostic accuracy, advanced imaging for suspected scaphoid fractures in the setting of negative radiographs represents a cost-effective strategy for reducing both costs and morbidity. The decision to use CT compared with MRI is a function of individual institutional costs and local test performance characteristics. Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.

  2. Occult fractures of the waist of the scaphoid: early diagnosis by high-spatial-resolution sonography.

    PubMed

    Hauger, Olivier; Bonnefoy, Olivier; Moinard, Maryse; Bersani, Daniel; Diard, François

    2002-05-01

    This study evaluated the diagnostic accuracy of high-spatial-resolution sonography in the diagnosis of occult fractures of the waist of the scaphoid. Sonography of the scaphoid bone with a 12-MHz transducer was performed in 54 patients with clinically suspected scaphoid fracture and normal findings on initial radiographs, including specific scaphoid images. Three levels of clinical suspicion were considered: high (20%), moderate (30%), and low (50%). Attention was paid to the continuity of the scaphoid cortex and to the surrounding soft tissues (i.e., hemarthrosis or hematoma). Data from early sonograms were then compared with the results of radiography repeated 10-14 days after the initial trauma. In cases of persistent suspicion despite normal findings on follow-up radiographs, the presence of fracture was evaluated on CT (four patients), MR imaging (one patient), or bone scanning (one patient). Follow-up examinations proved fracture of the scaphoid waist in five patients. In all patients, diagnosis of fracture was suspected on initial sonograms showing cortical disruption associated with soft-tissue abnormalities. There was one false-positive finding and no false-negative results. Using cortical disruption as a diagnostic criterion, we found the sensitivity, specificity, and accuracy of high-resolution sonography for the depiction of scaphoid fracture to be 100%, 98%, and 98%, respectively. Using soft-tissue abnormalities alone as a criterion, we found the sensitivity, specificity, and accuracy of high-resolution sonography to be 100%, 65%, and 68%, respectively. The overall prevalence of occult fracture was 9%, ranging from 3.7% for low suspicion to 27% for high suspicion of fracture. High-resolution sonography is a reliable and accurate method of evaluating occult fractures of the scaphoid waist. Cortical disruption is the diagnostic key. Soft-tissue abnormalities alone lack specificity.

  3. Diagnosis of occult scaphoid fracture with high-spatial-resolution sonography: a prospective blind study.

    PubMed

    Fusetti, C; Poletti, P A; Pradel, P H; Garavaglia, G; Platon, A; Della Santa, D R; Bianchi, S

    2005-09-01

    Evaluation of diagnostic accuracy of high-spatial-resolution sonography (HSR-S) in occult scaphoid fractures. HSR-S was performed in 24 patients with clinically suspected fracture and normal radiographs. Three levels of clinical suspicion were considered (high, intermediate, and low). Three levels of sonographic suspicion were defined on the basis of cortical interruption, radiocarpal effusion, and scapho-trapezium-trapezoid effusion. Three positive criteria were interpreted as being highly indicative of fracture. Data from sonograms were compared with computed tomography (CT) scans. CT scanning demonstrated a fracture of the scaphoid in five patients. The global sensitivity of HSR-S for detection of occult scaphoid fracture was 100% and the specificity 79%. All patients with demonstrated occult fracture had a high sonography index of suspicion. A high sonography index of suspicion was correlated with 100% sensitivity, specificity, positive predictive value, and negative predictive value. HSR-S is a reliable, available, and cost-effective method in early diagnosis of occult fractures of the scaphoid. The presence of three defined criteria is required to assess the diagnosis.

  4. Scaphoid Fracture of the Wrist

    MedlinePlus

    .org Scaphoid Fracture of the Wrist Page ( 1 ) The scaphoid is one of the small bones in the wrist. It is ... that the scaphoid is injured. Cause A scaphoid fracture is usually caused by a fall on an ...

  5. Occult fractures of the scaphoid: the role of ultrasonography in the emergency department.

    PubMed

    Platon, Alexandra; Poletti, Pierre-Alexandre; Van Aaken, Jan; Fusetti, Cesare; Della Santa, Dominique; Beaulieu, Jean-Yves; Becker, Christoph D

    2011-07-01

    To evaluate ultrasonography (US) performed by an emergency radiologist in patients with clinical suspicion of scaphoid fracture and normal radiographs. Sixty-two consecutive adult patients admitted to our emergency department with clinical suspicion of scaphoid fracture and normal radiographs underwent US examination of the scaphoid prior to wrist computed tomography (CT), within 3 days following wrist trauma. US examination was performed by a board-certified emergency radiologist, non-specialized in musculoskeletal imaging, using the linear probe (5-13 MHz) of the standard sonographic equipment of the emergency department. The radiologist evaluate for the presence of a cortical interruption of the scaphoid along with a radio-carpal or scapho-trapezium-trapezoid effusion. A CT of the wrist (reference standard) was performed in every patient, immediately after ultrasonography. Fractures were classified into two groups according to their potential for complication: group 1 (high potential, proximal or waist), group 2 (low-potential, distal or tubercle). A scaphoid fracture was demonstrated by CT in 13 (21%) patients: eight (62%) of them belonged to group 1 (three in the proximal pole, five in the waist), five (38%) to group 2 (three in the distal part, two in the tubercle). US was 92% sensitive (12/13) in demonstrating a scaphoid fracture. It was 100% sensitive (8/8) in demonstrating a fracture with a high potential of complication (group 1). Our data show that, in emergency settings, US can be used for the triage to CT in patients with clinical suspicion of scaphoid fracture and normal radiographs.

  6. The Effect of Scaphoid Fracture Site on Scaphoid Instability Patterns

    PubMed Central

    Werner, Frederick W.; St-Amand, Hugo; Moritomo, Hisao; Sutton, Levi G.; Short, Walter H.

    2015-01-01

    Background Scaphoid fractures are common carpal fractures that are often misdiagnosed as wrist sprains and may go on to nonunion. The location of the fracture site may influence the stability of scaphoid nonunions. Purpose To determine whether the stability of a scaphoid nonunion depends upon the fracture's location, we tested the hypothesis that a simulated fracture distal to the apex of the scaphoid dorsal ridge will have greater interfragmentary motion than proximal. Methods Eleven cadaver wrists were moved through three wrist motions using a wrist simulator. In six wrists, a fracture was created distal to the scaphoid apex, and in five a fracture was created proximal to the apex. Sensors attached to the distal and proximal parts of each scaphoid measured the interfragmentary motion during wrist motion. Results In those wrists in which the scaphoid was sectioned distal to the apex, the distal fragment became significantly more unstable relative to the proximal fragment. It flexed, ulnarly deviated, and pronated. These motion changes were less when the scaphoid was sectioned proximally. Discussion Scaphoid fractures distal to the scaphoid apex will have greater interfragmentary motion. The mobility of the fragments at the fracture site is possibly a more important contributory factor of nonunion in scaphoid waist fractures than for proximal scaphoid fractures. Clinical Relevance Understanding the effect that the location of a scaphoid fracture has on the potential for nonunion may influence the modalities of treatment and follow-up. PMID:26855836

  7. Inter-observer agreement between 2-dimensional CT versus 3-dimensional I-Space model in the Diagnosis of Occult Scaphoid Fractures

    PubMed Central

    Drijkoningen, Tessa; Knoter, Robert; Coerkamp, Emile G.; Koning, Anton H.J.; Rhemrev, Steven J.; Beeres, Frank J.

    2016-01-01

    Background: The I-Space is a radiological imaging system in which Computed Tomography (CT)-scans can be evaluated as a three dimensional hologram. The aim of this study is to analyze the value of virtual reality (I-Space) in diagnosing acute occult scaphoid fractures. Methods: A convenient cohort of 24 patients with a CT-scan from prior studies, without a scaphoid fracture on radiograph, yet high clinical suspicion of a fracture, were included in this study. CT-scans were evaluated in the I-Space by 7 observers of which 3 observers assessed the scans in the I-Space twice. The observers in this study assessed in the I-Space whether the patient had a scaphoid fracture. The kappa value was calculated for inter- and intra-observer agreement. Results: The Kappa value varied from 0.11 to 0.33 for the first assessment. For the three observers who assessed the CT-scans twice; observer 1 improved from a kappa of 0.33 to 0.50 (95% CI 0.26-0.74, P=0.01), observer 2 from 0.17 to 0.78 (95% CI 0.36-1.0, P<0.001), and observer 3 from 0.11 to 0.24 (95% CI 0.0-0.77, P=0.24). Conclusion: Following our findings the I-Space has a fast learning curve and has a potential place in the diagnostic modalities for suspected scaphoid fractures. PMID:27847847

  8. Percutaneous fixation of scaphoid fractures.

    PubMed

    Slade, J F; Jaskwhich, D

    2001-11-01

    The scaphoid proximal pole and waist fractures presented here were treated by a novel dorsal percutaneous technique with arthroscopic assistance. All fractures healed, with good final functional results and no complications. The advantages of the dorsal percutaneous approach to scaphoid fixation are: (1) the proximal-to-distal placement of the guide pin and screw allow for more precise placement along the central axis of the scaphoid, which decreases healing time and reduces risk of screw thread exposure. (2) The dorsal approach avoids injuring the vulnerable volar ligament anatomy. And (3) the insertion of the screw from the proximal to distal direction allows the more rigid fixation of proximal scaphoid fractures. Arthroscopy allows confirmation of fracture reduction and screw implantation as well as evaluation of concurrent ligament injuries not detected with standard imaging. Percutaneous K-wires act as joysticks to reduce and compress fracture fragments prior to fixation. The presented technique allows for early, rigid internal fixation with minimal associated morbidity. Patients successfully treated with this technique include those with stable and unstable acute fractures of the scaphoid at all locations, including the proximal pole. Nondisplaced fractures that present with delayed or fibrous union without evidence of avascular necrosis, cyst formation, or bony sclerosis may also be treated with this technique. This technique allows for faster rehabilitation and an earlier return to work or avocation without restriction once CT scan confirms a solid union. Some articles document extraordinary rapid healing by standard radiographs; however, we caution that scaphoid bone healing cannot accurately be determined without CT scan. Percutaneous, arthroscopically assisted internal fixation by a dorsal approach may be considered in all acute scaphoid fractures selected for surgical fixation. The dorsal guidewire permits dorsal and volar implantation of a cannulated

  9. Scaphoid fractures in the athlete.

    PubMed

    Winston, Mark J; Weiland, Andrew J

    2017-03-01

    Scaphoid fractures are a common wrist injury, especially in athletes. Clinicians should have a high index of suspicion for a scaphoid fracture in any patient complaining of radial-sided wrist pain after a fall on an outstretched hand. Advanced imaging, including CT and MRI scans, may be useful in diagnosis and classification of fracture patterns. Treatment varies based on the fracture location, stability of the fracture, and predictability of the fracture to heal. Treatment involves either non-operative management with a thumb spica cast or brace, or operative fixation with a headless compression screw, k-wires, or scaphoid-specific plates. Return to play is dependent on many variables, including sport, fracture union, and ability to play with cast.

  10. Scaphoid fractures: what's hot, what's not.

    PubMed

    Geissler, William B; Adams, Julie E; Bindra, Randy R; Lanzinger, William D; Slutsky, David J

    2012-01-01

    The scaphoid is the most commonly fractured carpal bone of the wrist. It is an unusual carpal bone in that it bridges both the proximal and the distal rows; this subjects it to continuous shearing and bending forces. Approximately 80% of the scaphoid is covered by cartilage, which limits its ligamentous attachment and vascular supply. Most scaphoid fractures occur at the waist. Acute stable fractures or incomplete fractures of the scaphoid may be treated nonsurgically; a high rate of union can be expected. However, there is considerable debate about the type of immobilization needed. Although closed treatment of stable wrist fractures of the scaphoid achieve a high rate of healing, prolonged cast immobilization may lead to complications, including muscle atrophy, possible joint contracture, and disuse osteopenia. Because of this, internal fixation of minimally displaced fractures of the scaphoid has recently become popular. There is consensus in the literature that nonunion of the scaphoid and proximal pole fractures should be treated surgically. In the past several decades, percutaneous arthroscopic techniques of scaphoid stabilization, which minimize surgical morbidity, have become popular. There also has been a significant improvement in the management of difficult scaphoid nonunions, with or without deformity. Improved techniques include open and dorsal approaches and vascularized bone grafting of resistant scaphoid nonunions. Declining in popularity is the prolonged immobilization of unstable fractures when surgical stabilization may have been a better treatment option.

  11. [Scaphoid fracture in motocross riders].

    PubMed

    Knobloch, K; Krämer, R; Redeker, J; Spies, M; Vogt, P M

    2009-12-01

    Motocross racing is a demanding motorcycling discipline with significant physiological and psychological demands. Upper extremity injuries are frequently encountered. Interestingly, motocross riders present with a significantly stronger left arm, even if the left hand is not dominant. This difference is attributed to the use of the clutch lever with the left hand, which is more frequent in motocross than in Enduro or desert rally. The wrist has been reported to be involved especially among motocross racers in contrast to road racing. Besides wrist fractures, scaphoid fractures have been previously without a detailed analysis of the injury mechanism. We report on three patients suffering scaphoid fractures caused by extreme hyperextension of the wrist during landing after a motocross jump. Two patients presented late three months following the initial trauma (both Herbert type C fractures), while one motocross athlete with a B 2-type scaphoid fracture was admitted to wrist surgery within a week. The B 2-type fracture was treated with open reduction and Herbert-screw fixation, while the C-type fractures were treated by Herbert-screw fixation in addition to a cortico-cancellous bone graft. Within ten weeks after the surgery the patients were back in sport at their given preoperative level. Hyperextension rather than wrist flexion appears as the predominant mechanism of wrist injuries in motocross riders. A more axial impact on the wrist is more likely to produce a radial fracture during the landing phase. Preventive strategies are internal muscular wrist stabilisation using eccentric training and external stabilisation by rigid gloves allowing only limited hyperextension.

  12. Managing scaphoid fractures. How we do it?

    PubMed Central

    Gupta, Vikas; Rijal, Laxman; Jawed, Akram

    2013-01-01

    The scaphoid is the common carpal bone to be fractured. Proper clinical and radiological evaluation is required to establish it's diagnosis. The management of acute fractures includes conservative treatment with cast in minimally displaced to open reduction and internal fixation in case of displaced ones. The established nonunion requires open reduction, bone grafting and internal fixation. PMID:26403769

  13. Scaphoid fracture in the elite athlete.

    PubMed

    Belsky, Mark R; Leibman, Matthew I; Ruchelsman, David E

    2012-08-01

    Scaphoid fracture remains a common, potentially devastating, injury that can impair upper extremity function. Early recognition with proper imaging and treatment provides the best opportunity to heal and return to a normal activity level. Surgical treatment offers the patient a quicker return to the rehabilitation of the extremity and therefore an earlier return to elite play. There is evidence that healing occurs faster if the fractured scaphoid is fixed with internal fixation. Absolute compliance by the athlete and the training program that surrounds the athlete is critical to protect the wrist while maintaining the necessary conditioning of an elite athlete. Copyright © 2012 Elsevier Inc. All rights reserved.

  14. Rotational stability in screw-fixed scaphoid fractures compared to plate-fixed scaphoid fractures.

    PubMed

    Jurkowitsch, Josef; Dall'Ara, E; Quadlbauer, S; Pezzei, Ch; Jung, I; Pahr, D; Leixnering, M

    2016-11-01

    The literature describes the treatment of scaphoid fractures comparing the volar and dorsal approaches, the advantages and disadvantages of percutaneous screw fixation, as well as the treatment of scaphoid nonunions using different types of cancellous or corticocancellous bone grafts. Yet, to date no studies are available comparing the outcome of rotational stability in screw-fixed scaphoid fractures to angular stable systems. The purpose of this study is to provide reliable data about rotational stability in stabilised scaphoid fractures and to gain information about the rigidity and the stability of the different types of fixation. Three groups of different stabilisation methods on standardised scaphoid B2 fractures were tested for rotational stability. Stabilisation was achieved using one or two cannulated compression screws (CCS) or angular stable plating. We performed ten repetitive cycles up to 10°, 20° and 30° rotation, measuring the maximum torque and the average dissipated work at angle level. Our study showed that rotational stability using a two CCS fixation is significantly (p < 0.05) higher than single CCS fixation. Using the angular stable plate system was also superior to the single CCS (p < 0.05). There was, however, no significant difference between two CCS fixation and angular stable plate fixation. Even though indications of using screws or plate systems might be different and plate osteosynthesis may be preferable in treatment of dislocated or comminuted fractures as well as for nonunions, our study showed a better rotational stability by choosing more than just one screw for osteosynthesis. Angular stable plating of scaphoid fractures also provides more rotational stability than single CCS fixation. The authors therefore hypothesise higher union rates in scaphoid fractures using more stable fixation systems.

  15. Scaphoid fracture: diagnosis and management.

    PubMed

    Bethel, Jim

    2009-07-01

    Nurses working in first-contact settings commonly assess and manage patients with suspected or actual injury to the scaphoid bone. In this article, lack of consensus on the assessment of such injuries, and on which treatment regimen and imaging techniques should be used, is discussed. The importance of being aware of the risk of avascular necrosis of the bone after injury is also emphasised.

  16. [Diagnosis of the scaphoid bone : Fractures, nonunion, circulation, perfusion].

    PubMed

    Kahl, T; Razny, F K; Benter, J P; Mutig, K; Hegenscheid, K; Mutze, S; Eisenschenk, A

    2016-11-01

    The clinical relevance of scaphoid bone fractures is reflected by their high incidence, accounting for approximately 60 % among carpal fractures and for 2-3 % of all fractures. With adequate therapy most scaphoid bone fractures heal completely without complications. Insufficient immobilization or undiagnosed fractures increase the risk of nonunion and the development of pseudarthrosis.X-ray examination enables initial diagnosis of scaphoid fracture in 70-80 % of cases. Positive clinical symptoms by negative x‑ray results require further diagnostics by multi-slice spiral CT (MSCT) or MRI to exclude or confirm a fracture. In addition to the diagnosis and description of fractures MSCT is helpful for determining the stage of nonunion. Contrast enhanced MRI is the best method to assess the vitality of scaphoid fragments.

  17. Carpal fractures other than scaphoid.

    PubMed

    Urch, Ekaterina Y; Lee, Steve K

    2015-01-01

    Carpal fractures are uncommon, but if missed, can lead to morbidity and loss of function, especially in an athlete. Early diagnosis through physical examination, plain radiographs, and possibly advanced imaging is paramount. Treatment is specific to each fracture type, and return to play varies with each clinical scenario. This article organizes current knowledge of these potentially difficult fractures with a table of diagnoses and treatment guidelines. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Comparison of conventional radiography and MDCT in suspected scaphoid fractures

    PubMed Central

    Behzadi, Cyrus; Karul, Murat; Henes, Frank Oliver; Laqmani, Azien; Catala-Lehnen, Philipp; Lehmann, Wolfgang; Nagel, Hans-Dieter; Adam, Gerhard; Regier, Marc

    2015-01-01

    AIM: To determine the diagnostic accuracy and radiation dose of conventional radiography and multidetector computed tomography (MDCT) in suspected scaphoid fractures. METHODS: One hundred twenty-four consecutive patients were enrolled in our study who had suffered from a wrist trauma and showed typical clinical symptoms suspicious of an acute scaphoid fracture. All patients had initially undergone conventional radiography. Subsequent MDCT was performed within 10 d because of persisting clinical symptoms. Using the MDCT data as the reference standard, a fourfold table was used to classify the test results. The effective dose and impaired energy were assessed in order to compare the radiation burden of the two techniques. The Wilcoxon test was performed to compare the two diagnostic modalities. RESULTS: Conventional radiography showed 34 acute fractures of the scaphoid in 124 patients (42.2%). Subsequent MDCT revealed a total of 42 scaphoid fractures. The sensitivity of conventional radiography for scaphoid fracture detection was 42.8% and its specificity was 80% resulting in an overall accuracy of 59.6%. Conventional radiography was significantly inferior to MDCT (P < 0.01) concerning scaphoid fracture detection. The mean effective dose of MDCT was 0.1 mSv compared to 0.002 mSv of conventional radiography. CONCLUSION: Conventional radiography is insufficient for accurate scaphoid fracture detection. Regarding the almost negligible effective dose, MDCT should serve as the first imaging modality in wrist trauma. PMID:25628802

  19. Fractures of the scaphoid, diagnosis and management--a review.

    PubMed

    Andjelković, Sladjana Z; Vucković, Cedo D; Lesić, Aleksandar R; Tulić, Goran C; Milutinović, Suzana M; Palibrk, Tomislav D; Zagorac, Slavisa G; Bumbasirević, Marko Z

    2013-01-01

    The scaphoid is vitally important for the proper mechanics of wrist function. Fracture of the scaphoid bone is the most common carpal fracture. Among all wrist injuries the incidence of scaphoid fracture is second only to fractures of the distal radius. Scaphoid fractures are significant because a delay in diagnosis can lead to a variety of adverse outcomes that include nonunion, delayed union, decreased grips strength, range of motion and osteoarthritis of the radiocarpal joint. To avoid missing this diagnosis, a high index of suspicion and a through history and physical examination are necessary, because initial radiographs are often negative. Regardless of the technique of bone grafting, there will almost always be some loss of motion even if the fracture unites.

  20. Scaphoid fracture: Bone marrow edema detected with dual-energy CT virtual non-calcium images and confirmed with MRI.

    PubMed

    Dareez, Nazeer M; Dahlslett, Kristine H; Engesland, Eirin; Lindland, Elisabeth S

    2017-07-29

    We aimed to determine whether bone marrow edema (BME) in acute traumatic scaphoid fracture could be demonstrated with dual-energy CT (DECT) using MRI as the gold standard. In recent years, virtual non-calcium (VNCa) images have been used to demonstrate BME in trauma cases, for example, in vertebral compression fractures, hip trauma to detect occult fractures and knee fractures. We present three cases of acute scaphoid trauma. Two patients had subtle or invisible fractures on x-ray and conventional CT images, while DECT VNCa images clearly visualized the BME, which was confirmed by MRI. One patient had negative findings on both VNCa and MRI images. The DECT VNCa algorithm is a promising technique to demonstrate BME in scaphoid fractures, with potential for increasing the diagnostic value of CT in this type of injury.

  1. Occult fractures of extremities.

    PubMed

    Ahn, Joong Mo; El-Khoury, Georges Y

    2007-05-01

    Recent advances in cross-sectional imaging, particularly in CT and MR imaging, have given these modalities a prominent role in the diagnosis of fractures of the extremities. This article describes the clinical application and imaging features of cross-sectional imaging (CT and MR imaging) in the evaluation of patients who have occult fractures of the extremities. Although CT or MR imaging is not typically required for evaluation of acute fractures, these modalities could be helpful in the evaluation of the occult osseous injuries in which radiographic findings are equivocal or inconclusive.

  2. Scaphoid Proximal Pole Fracture Following Headless Screw Fixation

    PubMed Central

    Rancy, Schneider K.; Zelken, Jonathan A.; Lipman, Joseph D.; Wolfe, Scott W.

    2015-01-01

    Background Headless screw fixation of scaphoid fractures and nonunions yields predictably excellent outcomes with a relatively low complication profile. However, intramedullary implants affect the load to failure and stress distribution within bone and may be implicated in subsequent fracture. Case Description We describe a posttraumatic fracture pattern of the scaphoid proximal pole originating at the previous headless screw insertion site in three young male patients with healed scaphoid nonunions. Each fracture was remarkably similar in shape and size, comprised the volar proximal pole, and was contiguous with the screw entry point. Treatment was challenging but successful in all cases. Literature Review Previous reports have posited that stress-raisers secondary to screw orientation may be implicated in subsequent peri-implant fracture of the femoral neck. Repeat scaphoid fracture after screw fixation has also been reported. However, the shape and locality of secondary fracture have not been described, nor has the potential role of screw fixation in the production of distinct fracture patterns. Clinical Relevance Hand surgeons must be aware of this difficult complication that may follow antegrade headless screw fixation of scaphoid fracture nonunion, and of available treatment strategies. PMID:26855840

  3. Fracture of the Scaphoid During a Bench-Press Exercise.

    PubMed

    Mason, John S; Crowell, Michael S; Goss, Donald L

    2015-08-01

    The patient was a 21-year-old male cadet at a military academy who was evaluated by a physical therapist in a direct-access capacity for a chief complaint of left wrist pain that began 1 day after injuring his wrist while performing a bench-press exercise. Due to concern for a scaphoid fracture and because radiographic imaging was not immediately available, a physical therapist credentialed to utilize fluoroscopy evaluated the left wrist. Radiographs were subsequently ordered, which confirmed a mid-waist, nondisplaced scaphoid fracture.

  4. Simultaneous fracture of the waist of the scaphoid and the hook of the hamate.

    PubMed

    Komura, Shingo; Suzuki, Yasushi; Ikehata, Tatsuya

    2010-01-01

    A case of simultaneous fracture of the waist of the scaphoid and the hook of the hamate is presented. The scaphoid fracture was treated surgically with a headless compression screw, while the hook fracture was treated conservatively with cast immobilisation for eight weeks. Both fractures achieved bone union and the patient returned to work without any symptoms or complications. Only two cases of fractures of the scaphoid and hamate have been reported previously. However, both of them involved fracture of the body of the hamate. This is the first report of simultaneous fracture of the scaphoid and the hook of the hamate.

  5. SCAPHOID STRESS FRACTURE IN GYMNASTICS ATHLETE: A CASE REPORT.

    PubMed

    Nakamoto, João Carlos; Saito, Mateus; Cunha, Ana Paula; Luques, Isabela Ugo

    2009-01-01

    We present a case report of an 18 year-old gymnast who was diagnosed with a scaphoid stress fracture associated with a distal radial epiphysiolysis, reporting the treatment of choice. After a brief literature review about this rare association, the authors ask for attention concerning the importance of physical and image examination in making right diagnosis and finding associated injuries.

  6. Acute scaphoidectomy and four-corner fusion for the surgical treatment of trans-scaphoid perilunate fracture dislocation with pre-existing scaphoid non-union.

    PubMed

    Roberts, Darren; Power, Dominic Michael

    2015-07-16

    This paper presents a rare case of trans-scaphoid perilunate fracture dislocation with concurrent scaphoid non-union of the left wrist following a motorcycle accident. Emergent CT identified scaphoid non-union advanced collapse and an acute scaphoidectomy, four-corner fusion, denervation and radiocarpal ligament repair was performed. 2015 BMJ Publishing Group Ltd.

  7. Current concepts for the treatment of acute scaphoid fractures.

    PubMed

    Arsalan-Werner, A; Sauerbier, M; Mehling, I M

    2016-02-01

    Fractures of the scaphoid are common injuries, accounting for approximately 80 % of carpal fractures. Differentiation between stable and unstable fractures (Herbert classification) cannot be made with conventional X-rays, so evaluation by computed tomography should additionally be performed. Under most circumstances, minimally invasive surgery with cannulated screws is the treatment of choice. A longer cast immobilization after minimal-invasive surgery is not necessary. Conservative treatment still has a place if the fracture is not dislocated nor unstable, but operative treatment can be offered to reduce the period of cast immobilization. Displaced fractures have a greater risk for nonunion and therefore should be treated operatively. Proximal pole fractures are definitely unstable, requiring treatment with screw fixation. The surgical approach depends on the location of the fracture and the preference of the surgeon.

  8. [C-type scaphoid fracture in a elite power lifting].

    PubMed

    Heckmann, A; Lahoda, L U; Alkandari, Q; Vogt, P M; Knobloch, K

    2008-06-01

    Power lifting injuries most often involve shoulder injuries with an injury rate of 0.57 to 0.71/1000 hours of power lifting. Wrist injuries are less common in power lifters with 0.05/1000 hours exposure vs. 0.23/1000 h in elite weight lifting men. Often, two contributing factors causing wrist injuries are encountered: a) loss of balance causing the barbell to drift back behind the head of the power lifter, which hyperextends the wrist and b) the maximal weight. We report on an elite power lifting athlete preparing for the World Masters Bench press championships suffering two months of persisting pain during bench press exercise and rest in the snuff-box area following a loss of balance of the bar-bell during bench press with 280 kg load. Following prolonged presentation 2 months after the initial injury with training in the meantime, CT-scan was performed revealing a C-type scaphoid fracture. Surgery was performed as Herbert screw fixation and bone grafting according to the technique of Matti-Russe, followed by an immobilisation of twelve weeks with a plaster. We recommended ending the athletes' power lifting career, however he further exercised with the plaster with consecutive re-operation 3months later and 2nd Matti-Russe and Herbert screw re-do. One year later he became national champion with 240 kg bench pressing. Given the limited scaphoid blood supply and the high complication rate especially among C-type scaphoid fractures, a surgical procedure with bone grafting, Herbert screw fixation and sufficient plaster immobilisation is advocated in scaphoid fractures in elite athletes.

  9. Isolated fracture-dislocation of the scaphoid's proximal pole treated by scaphoid internal fixation and scapho-lunate ligament reconstruction.

    PubMed

    Rosati, Marco; Parchi, Paolo; Lisanti, Michele

    2009-05-01

    We present a case of irreducible palmar dislocation of the proximal fragment of a scaphoid fracture without carpal dislocation. We observed this lesion 2 days after the injury and we immediately operated the patient with a combined volar and dorsal access: using the Henry access we reduced the fracture and we inserted a cannulated screw to synthesize the scaphoid, using the dorsal access we repaired the complete rupture of the scapho-lunate ligament using a mini anchor. Stabilization among scaphoid, lunate and capitate was performed using Kirschner wires. X-ray showed fracture healing after 90 days. No clinical or radiographic evidence of carpal instability was revealed, on standard X-rays or on dynamic evaluations. No sign of avascular necrosis or degenerative arthritis was observed after 9 months.

  10. Trans-Scaphoid Perilunate Fracture Dislocation; A Technical Note

    PubMed Central

    Aslani, Hossein; Bazavar, Mohammad Reza; Sadighi, Ali; Tabrizi, Ali; Elmi, Asghar

    2016-01-01

    Carpal fracture-dislocation is regarded as an unusual orthopedic injury and, thus, orthopedic surgeons are less experienced in dealing with and treating these fractures and dislocations. We report a 20-year-old worker man suffering from an unusual carpal fracture-dislocation. There was trans-scaphoid fracture and lunate dislocation with other carpal proximal bones toward volar of the wrist. Two volar and dorsal approaches were used to treat and stabilize the fracture. It was completely stabilized after open reduction and fixation using several pins. After two days, neural symptoms were completely recovered and the patient was discharged. Postoperative radiographies revealed complete restitution of lesser and greater arcs and normalization of Gilula's line. Scapholunate and lunatocapitate angles reached to less than 60° and 10°, respectively. The combined approach had favorable results for treatment of this unusual type of carpus fracture dislocation. However longer follow up is need to evaluate the arthritis and degenerative changes in wrist. PMID:27331069

  11. Tomosynthesis: A new radiologic technique for rapid diagnosis of scaphoid fractures.

    PubMed

    Compton, N; Murphy, L; Lyons, F; Jones, J; MacMahon, P; Cashman, J

    2016-12-21

    Scaphoid fractures constitute 71% of all carpal bone fractures.(1) Early diagnosis and treatment has significant bearing on fracture union rates and better clinical outcomes. While displaced fractures can be readily seen on plain radiograph, undisplaced fractures can require advanced imaging modalities to confirm that diagnosis. Advanced imaging such as Magnetic Resonance Imaging (MRI), Computerised tomography (CT) and bone scintigraphy are routinely used for the diagnosis of scaphoid fractures but require significant radiation exposure, increased cost and can be difficult to access.(2) Tomosynthesis is an emerging imaging modality which uses conventional x-ray systems to produce cross-sectional images. There has yet to be extensive research carried out investigating the diagnostic value of tomosynthesis in scaphoid fractures. The aim of this study is to optimise patient positioning for the diagnosis of scaphoid fractures in a cadaveric model and compare the diagnostic yield of tomography to conventional CT. Using four cadaveric specimens, three limb positions were examined in unfractured and fractured scaphoids to determine the optimal limb positions required for visualisation of the scaphoid. As a result of this study, the optimal position for visualisation of the scaphoid and diagnosis of scaphoid fractures has been determined. The results demonstrate that tomosynthesis is as effective as CT scanning in identifying scaphoid fractures in both sensitivity and specificity. By comparison to CT, tomosynthesis is cheaper, has lower radiation exposure, requires fewer hospital resources and can be performed quickly. Tomosynthesis is a valid diagnostic tool for the diagnosis of scaphoid fractures. Copyright © 2016 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier Ltd. All rights reserved.

  12. Classifications of Acute Scaphoid Fractures: A Systematic Literature Review.

    PubMed

    Ten Berg, Paul W; Drijkoningen, Tessa; Strackee, Simon D; Buijze, Geert A

    2016-05-01

    Background In the lack of consensus, surgeon-based preference determines how acute scaphoid fractures are classified. There is a great variety of classification systems with considerable controversies. Purposes The purpose of this study was to provide an overview of the different classification systems, clarifying their subgroups and analyzing their popularity by comparing citation indexes. The intention was to improve data comparison between studies using heterogeneous fracture descriptions. Methods We performed a systematic review of the literature based on a search of medical literature from 1950 to 2015, and a manual search using the reference lists in relevant book chapters. Only original descriptions of classifications of acute scaphoid fractures in adults were included. Popularity was based on citation index as reported in the databases of Web of Science (WoS) and Google Scholar. Articles that were cited <10 times in WoS were excluded. Results Our literature search resulted in 308 potentially eligible descriptive reports of which 12 reports met the inclusion criteria. We distinguished 13 different (sub) classification systems based on (1) fracture location, (2) fracture plane orientation, and (3) fracture stability/displacement. Based on citations numbers, the Herbert classification was most popular, followed by the Russe and Mayo classifications. All classification systems were based on plain radiography. Conclusions Most classification systems were based on fracture location, displacement, or stability. Based on the controversy and limited reliability of current classification systems, suggested research areas for an updated classification include three-dimensional fracture pattern etiology and fracture fragment mobility assessed by dynamic imaging.

  13. Classifications of Acute Scaphoid Fractures: A Systematic Literature Review

    PubMed Central

    Ten Berg, Paul W.; Drijkoningen, Tessa; Strackee, Simon D.; Buijze, Geert A.

    2016-01-01

    Background In the lack of consensus, surgeon-based preference determines how acute scaphoid fractures are classified. There is a great variety of classification systems with considerable controversies. Purposes The purpose of this study was to provide an overview of the different classification systems, clarifying their subgroups and analyzing their popularity by comparing citation indexes. The intention was to improve data comparison between studies using heterogeneous fracture descriptions. Methods We performed a systematic review of the literature based on a search of medical literature from 1950 to 2015, and a manual search using the reference lists in relevant book chapters. Only original descriptions of classifications of acute scaphoid fractures in adults were included. Popularity was based on citation index as reported in the databases of Web of Science (WoS) and Google Scholar. Articles that were cited <10 times in WoS were excluded. Results Our literature search resulted in 308 potentially eligible descriptive reports of which 12 reports met the inclusion criteria. We distinguished 13 different (sub) classification systems based on (1) fracture location, (2) fracture plane orientation, and (3) fracture stability/displacement. Based on citations numbers, the Herbert classification was most popular, followed by the Russe and Mayo classifications. All classification systems were based on plain radiography. Conclusions Most classification systems were based on fracture location, displacement, or stability. Based on the controversy and limited reliability of current classification systems, suggested research areas for an updated classification include three-dimensional fracture pattern etiology and fracture fragment mobility assessed by dynamic imaging. PMID:27104083

  14. Transtrapezial Approach for Fixation of Acute Scaphoid Fractures: Rationale, Surgical Techniques, and Results: AAOS Exhibit Selection.

    PubMed

    Verstreken, Frederik; Meermans, Geert

    2015-05-20

    The ideal position for a screw used for scaphoid fixation is central. The purpose of this study was to compare the current volar percutaneous approaches used for scaphoid fracture fixation, explore different options to improve central screw placement, and describe our experience with the transtrapezial approach.

  15. Scaphoid Fracture in a Patient with a Scaphotrapezial Synostosis: A Case Report and Literature Review

    PubMed Central

    Ali, Mohammed; Fallahi, Farshid; Dehler, Thomas

    2017-01-01

    Introduction. Scaphotrapezial synostosis has been rarely reported in the literature and only one case underwent surgical treatment for scaphoid fracture. Presentation of Case. A 15-year-old male presented with a painful left wrist following a fall. The initial radiographs showed a displaced scaphoid proximal pole fracture and a Scaphotrapezial synostosis. The fracture was then fixed percutaneously with satisfactory outcome. Discussion. Scaphotrapezial synostoses are very rare and most found in patients with multiple congenital anomalies or as part of a hereditary syndrome. They have previously been reported; however, we found only one case reporting a concomitant scaphoid fracture. Conclusion. This is the second case of its kind to report surgical treatment of scaphoid fracture associated with a congenital Scaphotrapezial synostosis. PMID:28197353

  16. Retrospective review of 234 scaphoid fractures and nonunions treated with arthroscopy for union and complications.

    PubMed

    Slade, J F; Gillon, T

    2008-01-01

    The purpose of this paper is to retrospectively review 234 consecutive cases of scaphoid fractures and nonunions treated using arthroscopy with the dorsal percutaneous implantation of a headless compression screw for healing and complications. Solid union of fracture is determined by CT scan. We identified 126 acute injuries, including 65 proximal pole fractures; 67 grossly displaced fractures; 12 trans-scaphoid perilunate dislocations including four trans-scaphoid trans-capitate fractures; and ten combined scaphoid and distal radius fractures. 108 scaphoid nonunions were identified. 98 were correctly aligned and ten had a humpback deformity which was correctable using arthroscopic assisted reduction techniques at the time of surgery. 82 presented with a fracture gap 2mm or greater requiring percutaneous bone grafting. 12 cases of avascular necrosis (AVN) were identified by MRI. 20 nonunions had surgery performed at other institutions. The mean time to surgery for the nonunions was 20 months. 99% union rate of acute scaphoid fractures was obtained by 12 weeks, as determined by CT scan. Two complications were identified (3%). One case of delayed healing was identified. this delayed union was treated with percutaneous bone grafting and continued on to heal uneventfully. The other complication was a case of volar trans-scaphoid peri-lunate dislocation. While the fracture healed, the patient developed a traumatic dislocation requiring a capitate-lunate arthrodesis. Treatment of scaphoid nonunions resulted in ten cases of delayed healing, which were treated with repeat percutaneous bone grafting. This represented a 9% complication rate. of the ten cases of delayed unions that were re-bone grafted, four failed to heal by nine months. This resulted in a 96% union rate of our nonunion group by nine months. when acute fracture healing was compared to nonunions the average healing of acute fractures as determined by CT scanning measuring trabecular bridging was 12 weeks

  17. Acute coronal plane scaphoid fracture and scapholunate dissociation from an axial load: a case report.

    PubMed

    Shin, Alexander Y; Horton, Todd; Bishop, Allen T

    2005-03-01

    Coronal fractures of the scaphoid are rare and can be difficult to diagnose. Axial load injuries that result in a complete coronal fracture of the scaphoid associated with an acute scapholunate dissociation are exceedingly rare. In our patient the radiographic finding of wide scapholunate dissociation was obvious; however, the coronal scaphoid fracture was not recognized initially nor suspected. During surgery the coronal scaphoid fracture was identified, reduced anatomically, and fixed with a compression screw. The scapholunate ligament also was repaired. A good result was obtained with return to sports with extension of 60 degrees and flexion of 70 degrees , grip strength equal to that of the uninjured wrist, and no radiographic problems (arthrosis, avascular necrosis, nonunion).

  18. The pediatric fracture of the scaphoid in patients aged 13 years and under: an epidemiological study.

    PubMed

    Ahmed, Issaq; Ashton, Fiona; Tay, Wy Keat; Porter, Daniel

    2014-03-01

    Fractures of the scaphoid are uncommon in the pediatric population. Despite their rarity, a significant number of children are referred to the fracture clinic for a suspected scaphoid fracture. The aim of this study was to report on the current incidence, pattern of injury, and the long-term outcomes following this injury in the pediatric population. Analysis of all pediatric scaphoid fractures presenting to a tertiary pediatric hospital (aged 13 y and under) over a 5-year period was performed. The case notes, radiographs, and other imaging studies for these patients were reviewed. Long-term functional outcome was assessed using Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire. Fifty-six patients of the 838 (6.7%) referred for a suspected scaphoid fracture were identified as having a confirmed diagnosis of a scaphoid fracture, giving an average annual incidence of 11 per 100,000. This group consisted of 39 boys (70%) and 17 girls (30%). The average age of incidence in boys was 12.2 years and in girls was 10.3 years (P<0.001). No scaphoid fractures were observed in boys below the age of 11 years and in girls below the age of 9 years. The most common type of fracture was a distal pole fracture (45 patients). One patient sustained a proximal pole fracture and went on to develop a nonunion. The duration of treatment in cast was shorter in distal pole fractures than in other types (P<0.001). At a mean follow-up of 70 months (range, 46 to 104 mo), 60% reported no limitation or impact when reporting a range of daily functional activities (mean DASH score=3.0). There is a suggestion that the overall incidence of scaphoid fractures in the pediatric population is increasing, but children aged 13 years and under continue to maintain a distinct fracture pattern when compared with adolescents and adults. The majority involves the distal third of the scaphoid and carries a good prognosis with conservative management. Prognostic study, Level 4.

  19. Trans-scaphoid perilunate dislocation with fractured carpal bones in a child.

    PubMed

    Ji, J-H; Shafi, M; Moon, C-Y; Park, S-E

    2010-02-01

    Transcarpal fractures and dislocations in children are rarely reported in the orthopedics literature. This is a report of a 10-year-old boy who sustained a trans-scaphoid perilunate dislocation with fractures across the carpal structure: these included injuries to the scaphoid, capitate and triquetrum bones. Treatment consisted in a closed reduction for the dislocation and using the dorsal approach of an open reduction with internal fixation of the fractures. The injury healed well with a full return of good wrist function. This unusual pattern of injury is described so that it may be more readily appreciated in the future.

  20. [Concomitant fractures of the radius and scaphoid with an elbow dislocation].

    PubMed

    El Andaloussi, Y; Bendriss, A; Bennouna, D; Ouarab, M

    2008-09-01

    A variety of associated injuries of the upper limb have been described in the literature. The authors report a case of bifocal fracture of the radius and a scaphoid fracture together with elbow dislocation. In our knowledge, this association of lesions has never previously been described.

  1. Incorrect radiographic evaluation after vascularized bone grafting for scaphoid fracture or nonunion

    PubMed Central

    Morin, Paul; Reindl, Rudy; Berry, Gregory K; Harvey, Edward J

    2011-01-01

    PURPOSE: The present study is a review of patients with scaphoid non-unions treated with a dorsal vascularized bone graft. The study highlights a subset of patients incorrectly diagnosed as graft failures. METHODS: A retrospective review of patients who received vascularized grafts for scaphoid nonunions was performed over a four-year period. The vascularized graft of choice for this group was the dorsal radial extensor compartment artery. RESULTS: Five patients from a scaphoid fracture group who were treated with vascularized grafts were diagnosed as being failures (average of five months). None of these patients had tenderness on palpation of the scaphoid, and they were scheduled for revised vascularized grafts. All patients at the time of surgery were found to have healed. These patients were treated with arthrolysis, resulting in healing and full range of motion. CONCLUSIONS: Scaphoid vascularized grafts may have a markedly delayed radiographic healing time. Reoperation to perform secondary vascularized procedures may result in unnecessary surgery. Early imaging following a scaphoid vascularized graft may be inaccurate and may demonstrate a continued nonunion. PMID:22379374

  2. Evaluation for Occult Fractures in Injured Children

    PubMed Central

    French, Benjamin; Song, Lihai; Feudtner, Chris

    2015-01-01

    OBJECTIVES: To examine variation across US hospitals in evaluation for occult fractures in (1) children <2 years old diagnosed with physical abuse and (2) infants <1 year old with injuries associated with a high likelihood of abuse and to identify factors associated with such variation. METHODS: We performed a retrospective study in children <2 years old with a diagnosis of physical abuse and in infants <1 year old with non-motor vehicle crash–related traumatic brain injury or femur fractures discharged from 366 hospitals in the Premier database from 2009 to 2013. We examined across-hospital variation and identified child- and hospital-level factors associated with evaluation for occult fractures. RESULTS: Evaluations for occult fractures were performed in 48% of the 2502 children with an abuse diagnosis, in 51% of the 1574 infants with traumatic brain injury, and in 53% of the 859 infants with femur fractures. Hospitals varied substantially with regard to their rates of evaluation for occult fractures in all 3 groups. Occult fracture evaluations were more likely to be performed at teaching hospitals than at nonteaching hospitals (all P < .001). The hospital-level annual volume of young, injured children was associated with the probability of occult fracture evaluation, such that hospitals treating more young, injured patients were more likely to evaluate for occult fractures (all P < .001). CONCLUSIONS: Substantial variation in evaluation for occult fractures among young children with a diagnosis of abuse or injuries associated with a high likelihood of abuse highlights opportunities for quality improvement in this vulnerable population. PMID:26169425

  3. Scaphoid fractures in children and adolescents: contemporary injury patterns and factors influencing time to union.

    PubMed

    Gholson, J Joseph; Bae, Donald S; Zurakowski, David; Waters, Peter M

    2011-07-06

    Historically, scaphoid fractures in children and adolescents have predominantly involved the distal pole, requiring neither surgical care nor extended follow-up. Changing patient characteristics, however, appear to be altering fracture epidemiology and treatment. The purpose of this investigation was to characterize contemporary fracture patterns in children and adolescents and to identify factors influencing time to healing following both nonoperative and operative treatment. A retrospective analysis of 351 scaphoid fractures that had been treated from 1995 to 2010 was performed to characterize fracture patterns. The mean patient age was 14.6 years (range, seven to eighteen years). Complete clinical and radiographic follow-up data were available for 312 fractures (89%), with 222 fractures presenting acutely and ninety not acutely. Union rates following casting or surgical treatment were determined, and Cox regression analysis was utilized to identify factors influencing both the union rate and the time to union. Overall, 248 fractures (71%) occurred at the scaphoid waist, eighty-one (23%) occurred at the distal pole, and twenty-two (6%) occurred at the proximal pole. Male sex, high-energy mechanisms of injury, closed physes, and high body-mass index were associated with fractures of the waist or proximal pole. Treatment of acute fractures with casting alone resulted in a 90% union rate. Lower union rates were seen in association with the use of casting alone for the treatment of chronic fractures, displaced fractures, and proximal fractures. Longer time to union was seen in association with older fractures, displaced fractures, proximal fractures, and fractures in patients with osteonecrosis. The union rate following surgery was 96.5% (109 of 113). Increased time to union was seen in association with open physes, fracture displacement, proximal fracture, the type of screw used for surgical fixation, and the use of bone graft at the time of surgery. With changes in

  4. Scaphoid fracture fixation: localization of bones through statistical model to ultrasound registration

    NASA Astrophysics Data System (ADS)

    Anas, Emran Mohammad Abu; Rasoulian, Abtin; St. John, Paul; Pichora, David; Mousavi, Parvin; Lessoway, Victoria A.; Seitel, Alexander; Hacihaliloglu, Ilker; Rohling, Robert; Abolmaesumi, Purang

    2015-03-01

    Percutaneous treatment of scaphoid fractures has found increasing interest in recent years as it promises to minimize soft-tissue damage, and minimizes the risk of infections and the loss of the joint stability. However, as this procedure is mostly performed on 2D fluoroscopic images, the accurate localization of the scaphoid bone for fracture fixation renders extremely challenging. In this work, we thus propose the integration of a statistical wrist model with 3D intraoperative ultrasound for accurate localization of the scaphoid bone. We utilize a previously developed statistical wrist model and register it to bone surfaces in ultrasound images using a probabilistic approach that involves expectation-maximization. We utilize local phase symmetry to detect features in noisy ultrasound images; in addition, we use shadow information in ultrasound images to enhance and set apart bone from other features. Feasibility experiments are performed by registering the wrist model to 3D ultrasound volumes of two different wrists at two different wrist positions. And the result indicates a potential of the proposed technique for localization of the scaphoid bone in ultrasound images.

  5. The scaphoid.

    PubMed

    Sendher, Rosie; Ladd, Amy L

    2013-01-01

    The scaphoid is vitally important for the proper mechanics of wrist function. Its unique morphology from its boat like shape to its retrograde blood supply can present with challenges in the presence of a fracture. Almost completely covered with articular cartilage, this creates precise surface loading demands and intolerance to bony remodeling. Fracture location compounds risk of malunion and non-union. Scaphoid fractures may significantly impair wrist function and activities of daily living, with both individual and economic consequences. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Pulsed Electromagnetic Fields in the treatment of fresh scaphoid fractures. A multicenter, prospective, double blind, placebo controlled, randomized trial.

    PubMed

    Hannemann, Pascal; Göttgens, Kevin W A; van Wely, Bob J; Kolkman, Karel A; Werre, Andries J; Poeze, Martijn; Brink, Peter R G

    2011-05-06

    The scaphoid bone is the most commonly fractured of the carpal bones. In the Netherlands 90% of all carpal fractures is a fracture of the scaphoid bone. The scaphoid has an essential role in functionality of the wrist, acting as a pivot. Complications in healing can result in poor functional outcome. The scaphoid fracture is a troublesome fracture and failure of treatment can result in avascular necrosis (up to 40%), non-union (5-21%) and early osteo-arthritis (up to 32%) which may seriously impair wrist function. Impaired consolidation of scaphoid fractures results in longer immobilization and more days lost at work with significant psychosocial and financial consequences.Initially Pulsed Electromagnetic Fields was used in the treatment of tibial pseudoarthrosis and non-union. More recently there is evidence that physical forces can also be used in the treatment of fresh fractures, showing accelerated healing by 30% and 71% reduction in nonunion within 12 weeks after initiation of therapy. Until now no double blind randomized, placebo controlled trial has been conducted to investigate the effect of this treatment on the healing of fresh fractures of the scaphoid. This is a multi center, prospective, double blind, placebo controlled, randomized trial. Study population consists of all patients with unilateral acute scaphoid fracture. Pregnant women, patients having a life supporting implanted electronic device, patients with additional fractures of wrist, carpal or metacarpal bones and pre-existing impairment in wrist function are excluded. The scaphoid fracture is diagnosed by a combination of physical and radiographic examination (CT-scanning).Proven scaphoid fractures are treated with cast immobilization and a small Pulsed Electromagnetic Fields bone growth stimulating device placed on the cast. Half of the devices will be disabled at random in the factory.Study parameters are clinical consolidation, radiological consolidation evaluated by CT-scanning, functional

  7. The influence of wire positioning upon the initial stability of scaphoid fractures fixed using Kirschner wires A finite element study.

    PubMed

    Ezquerro, F; Jiménez, S; Pérez, A; Prado, M; de Diego, G; Simón, A

    2007-07-01

    A finite element model of the carpal scaphoid and its joints was developed to study how wire positioning affects the initial stability of the fixation of scaphoid waist fractures using Kirschner wires. A transverse fracture of the scaphoid waist was simulated along with its fixation using five different two-wire configurations. The resulting models were subjected to a load simulating a 200N force passing through the wrist. Friction between bony fragments was taken into account; as the friction coefficient of cancellous bone is unknown, three different values were analysed. For each of these friction coefficient values, the smallest transverse interfragmentary displacements, and consequently maximum initial stability, were obtained for the model that simulated the maximum gap between wires in the plane of fracture. Results also show that for a similar gap in the plane of fracture, more stable fixation can be achieved when wires cross each other not only in the frontal plane of the hand, but also perpendicularly to it.

  8. Variability in orthopedic surgeon treatment preferences for nondisplaced scaphoid fractures: A cross-sectional survey.

    PubMed

    Paulus, Megan Carroll; Braunstein, Jake; Merenstein, Daniel; Neufeld, Steven; Narvaez, Michael; Friedland, Robert; Bruce, Katherine; Pfaff, Ashley

    2016-12-01

    The absence of a best practice treatment standard contributes to clinical variation in medicine. Often in the absence of evidence, a standard of care is developed and treatment protocols are implemented. The purpose of this study was to examine whether the standard of care for the treatment of nondisplaced scaphoid fractures is uniform among orthopedic surgeons. A survey of orthopedic surgeons actively practicing in the US or abroad was conducted to elicit preferred treatment strategies for nondisplaced scaphoid fractures. The surgeons were recruited at orthopedic conferences, clinical visits, and via email. The survey included demographic questions along with a short clinical vignette. The option for fracture management included surgical versus nonsurgical treatment. For those who chose nonsurgical treatment, type/duration of immobilization was recorded. Cost analysis was performed to estimate direct and indirect costs of various treatment options. A total of 494 orthopedic surgeons completed the survey. The preference for surgical treatment was preferred in 13% of respondents. Hand/upper extremity specialists were significantly more likely to operate compared with generalists (p = 0.0002). Surgeons younger than forty-five were nearly twice as likely to choose surgery (p = 0.01). There was no clear consensus on duration of immobilization as 30% of surgeons chose 6 weeks, 33% selected 8 weeks, and 27% opted for 12 weeks. Total cost of surgery was 49% greater than that of nonoperative treatment. With each additional week of immobilization for nonoperative treatment, the total costs of surgical treatment near that of nonoperative treatment. There exist clear trends in how specific demographic groups choose to treat the nondisplaced scaphoid fracture. Whether these trends are the result of generational gaps or additional subspecialty training remains difficult to determine, but there is need to pursue a more consistent approach that benefits the patients and the

  9. Arthroscopically assisted percutaneous fixation for trans-scaphoid perilunate fracture dislocation.

    PubMed

    Jeon, I-H; Kim, H-J; Min, W-K; Cho, H-S; Kim, P-T

    2010-10-01

    Trans-scaphoid perilunate fracture dislocation is a complex carpal dislocation causing marked disruption of the carpal structures. Open treatment has been accepted as standard for this injury. We have used arthroscopically assisted percutaneous screw fixation and bone grafting to treat this injury in four patients. The functional outcome was good. All patients achieved solid union without nonunion or malunion. The complication and morbidity was relatively low; all patients had proper alignment and there was no evidence of instability or avascular necrosis or midcarpal arthritis.

  10. Bone density comparison of selected carpal and tarsal bones: validation for their use in compression fracture fixation studies of scaphoid screws.

    PubMed

    Brutus, J P; Rajkumar, J S; Rust, E; Harley, B J; Palmer, A K; Werner, F W

    2006-06-01

    To determine if trabecular, total and cortical bone densities of the capitate, navicular, cuboid, and first cuneiform were equivalent to those of the scaphoid, such that these bones could be used in place of the scaphoid in evaluating new headless scaphoid compression screws. Fifty scaphoids, capitates, naviculars, cuboids, and first cuneiforms were harvested from fresh frozen cadavers. The trabecular, total and cortical bone densities were measured using pQCT technology and statistically compared. A paired t comparison between paired scaphoids and capitates showed no difference between the trabecular bone densities. However, their total bone and cortical densities were found to be different. An independent measures ANOVA comparison of the five bones, showed no significant difference in mean trabecular density between the capitates, naviculars and first cuneiforms when compared to the scaphoids. However, the mean total and cortical densities of the first cuneiforms were less than the scaphoids and the mean trabecular, total and cortical bone densities of the cuboids were all less than the scaphoids. Compression fracture fixation studies of headless compression screws could be conducted using the capitate, navicular, and first cuneiform as models of the scaphoid when the supply of scaphoids is limited.

  11. Comparative Study of the Diagnostic Value of Panoramic and Conventional Radiography of the Wrist in Scaphoid Fractures

    PubMed Central

    Ezoddini Ardakani, Fatemeh; Zangoie Booshehri, Maryam; Banadaki, Seyed Hossein Saeed; Nafisi-Moghadam, Reza

    2012-01-01

    Background Scaphoid fractures are the most common type of carpal fractures. Objectives The aim of the study was to compare the diagnostic value of panoramic and conventional radiographs of the wrist in scaphoid fractures. Patients and Methods The panoramic and conventional radiographs of 122 patients with acute and chronic wrist trauma were studied. The radiographs were analyzed and examined by two independent radiologist observers; one physician radiologist and one maxillofacial radiologist. The final diagnosis was made by an orthopedic specialist. Kappa test was used for statistical calculations, inter- and intra-observer agreement and correlation between the two techniques. Results Wrist panoramic radiography was more accurate than conventional radiography for ruling out scaphoid fractures. There was an agreement in 85% or more of the cases. Agreement values were higher with better inter and intra observer agreement for panoramic examinations than conventional radiographic examinations. Conclusion The panoramic examination of the wrist is a useful technique for the diagnosis and follow-up of scaphoid fractures. Its use is recommended as a complement to conventional radiography in cases with inconclusive findings. PMID:23599708

  12. Functional Outcomes After Treatment of Scaphoid Fractures in Children and Adolescents.

    PubMed

    Bae, Donald S; Gholson, James J; Zurakowski, David; Waters, Peter M

    2016-01-01

    Little is known about longer-term functional outcomes of children treated for scaphoid fractures. We hypothesized that with appropriate treatment, functional outcomes would be consistent with population norms and would not vary between patients treated with cast-immobilization versus surgery. We further hypothesized that osteonecrosis and chronic nonunion would each be independent predictors of worse functional outcomes. Sixty-three of 312 patients (20%), age 8 to 18 years at the time of treatment, completed the Disability of the Arm, Shoulder, and Hand (DASH) inventory, DASH work and sports modules, and the Modified Mayo Wrist Score (MMWS) at a median follow-up time of 6.3 years (range, 2.6 to 17.7 y) from injury. Thirty-nine patients presented initially with acute scaphoid fractures, and 24 patients presented with chronic nonunions. Six of the 39 acute fractures and 20 of 24 nonunions were treated surgically. Univariate analysis and multivariate linear regression were used to identify predictors of MMWS and DASH scores. All patients went on to successful bony healing. The median DASH score for the cohort was 1 (interquartile range [IQR]: 0 to 4), with more than 95% of respondents reporting functional status equivalent to or better than the general population. Multivariate analysis demonstrated that chronic fracture presentation (P<0.001) and osteonecrosis (P=0.013) were each independent predictors of a worse outcome. Results of the DASH Work and Sports Modules as well as the MMWS corroborated the results found using the DASH. Surgical treatment was not found to influence functional status. The median MMWS for both surgical and nonsurgical patients was 100, representing excellent functional outcome. Children and adolescents with scaphoid fractures that achieve union have excellent outcomes at mid-term follow-up, with no difference in outcomes between casting and surgery. Although patients treated for nonunions and osteonecrosis have significantly decreased wrist

  13. Bioabsorbable fixation of scaphoid fractures and non-unions; analysis of early clinical outcomes.

    PubMed

    Ya'ish, F; Bailey, C A; Kelly, C P; Craigen, M A

    2013-01-01

    The vast majority of devices used for internal fixation of the scaphoid are metallic. This two-center study aimed to report the results of scaphoid fixation using a cannulated, bioabsorbable device made from a hydroxyapatite and poly-L-lactide composite in 29 consecutive patients. Fixation was performed for seven acute fractures and twenty-two established non-unions. Union was achieved in 72.4% of patients. Six of the acute fractures and fifteen of the non-unions united successfully. Modified Mayo Wrist Score ranged between good to excellent in all patients who successfully united, whereas patients who failed to unite ranged between poor to excellent, with one poor and two moderate scores. No adverse biocompatibility reactions were seen. Two failures with broken screws were re-explored and one of these was thought to be due to screw mal-placement. The device used is an alternative to conventional metal implants and produces comparable union rates to metallic devices in the short term.

  14. The Role of Lunate Morphology on Scapholunate Instability and Fracture Location in Patients Treated for Scaphoid Nonunion

    PubMed Central

    Kim, Byoung-Jin; Kovacevic, David; Lee, Young-Min; Seol, Jong-Hwan

    2016-01-01

    Background To determine the association between lunate morphology and the scapholunate instability using radiographic images, and investigate the association between lunate morphology and scaphoid fracture location. Methods Between January 2003 and December 2011, we retrospectively evaluated the plain radiographs and computed tomography (CT) images of 70 patients who underwent surgical intervention for a scaphoid nonunion, in order to determine the association between lunate type (I or II) and scapholunate instability or scaphoid fracture location. We determined the scaphoid fracture location using the fragment ratio and measured the radiolunate angle and capitate-triquetrum (C-T) distance. Results A type II lunate was present in 68.6% (48 of 70 cases). Mean fragment ratio of fracture location was 50.6% in the type II lunate group and 56.2% in the type I lunate group (p = 0.032). Sixteen of the 70 patients had dorsal intercalated segmental instability (DISI) deformities. Nine of 22 cases showed DISI deformity in type I lunate and 7 of 48 cases showed DISI deformity in type II lunate (p = 0.029). However, there were no significant differences between the presence of DISI deformity and fracture location (p = 0.15). Morphologic comparisons by both plain radiography and CT indicated a mean C-T distance in the type I lunate group (22 cases) of 2.3 mm and 5.0 mm in the type II lunate group (48 cases). The C-T distances were significantly correlated with lunate morphology (p = 0.001). Conclusions A type II lunate was associated with low incidence of DISI deformity and proximal location of fracture in patients presenting with a scaphoid nonunion. PMID:27247743

  15. Three-dimensional comparison of alternative screw positions versus actual fixation of scaphoid fractures.

    PubMed

    Volk, Ido; Gal, Jonathan; Peleg, Eran; Almog, Gil; Luria, Shai

    2017-06-01

    The recommended technique for the fixation of a scaphoid waist fracture involves a headless compression screw placed in the proximal fragment center. This is usually accomplished by placing a longitudinal axis screw as visualized by fluoroscopy. The screw length has been shown to have a biomechanical advantage. An alternative to these options, which has been debated in the literature, is a screw placed perpendicular to the fracture plane and in its center. The perpendicular screw may have a biomechanical advantage despite the fact that it may be shorter. This study examined the differences in location and length in actual patients between a screw in the center of the proximal fragment with a longitudinal axis screw, and the actual fixating screw. These were then compared to a perpendicular axis screw. Pre- and post-operative CT scans of 10 patients with scaphoid waist fractures were evaluated using a 3D computer model. Comparisons were made between the length, location and angle of actual and virtual screw alternatives; namely, a screw along the central third of the proximal fragment (central screw axis) where the scaphoid longitudinal axis was calculated mathematically (longitudinal screw axis) and a screw placed at 90° to the fracture plane and in its center (perpendicular screw axis). The longitudinal axis screw was found to be significantly longer than the other axes (28.3mm). There was a significant difference between the perpendicular axis screw and the location and angle of the other screw axis, but it was only shorter than the longitudinal screw (23.6mm versus 25.5mm for the actual screw; ns.). A computed longitudinal axis screw is longer than a central or actual screw placed longitudinally by visual inspection by the surgeon. Although it needs to be placed using computer assisted (CAS) techniques, it may have the biomechanical advantages of a longer screw in a similar trajectory. The perpendicular screw was found to be significantly different in position

  16. Bone scanning in the detection of occult fractures

    SciTech Connect

    Batillas, J.; Vasilas, A.; Pizzi, W.F.; Gokcebay, T.

    1981-07-01

    The potential role of bone scanning in the early detection of occult fractures following acute trauma was investigated. Technetium 99m pyrophosphate bone scans were obtained in patients with major clinical findings and negative or equivocal roentgenograms following trauma. Bone scanning facilitated the prompt diagnosis of occult fractures in the hip, knee, wrist, ribs and costochondral junctions, sternum, vertebrae, sacrum, and coccyx. Several illustrative cases are presented. Roentgenographic confirmation occurred following a delay of days to weeks and, in some instances, the roentgenographic findings were subtle and could be easily overlooked. This study demonstrates bone scanning to be invaluable and definitive in the prompt detection of occult fractures.

  17. Routine Imaging after Operatively Repaired Distal Radius and Scaphoid Fractures: A Survey of Hand Surgeons

    PubMed Central

    Bohl, Daniel D.; Lese, Andrea B.; Patterson, Joseph T.; Grauer, Jonathan N.; Dodds, Seth D.

    2014-01-01

    Background There is currently no standard of care for imaging after hand and upper-extremity procedures, and current imaging practices have not been characterized. Questions/Purposes To characterize current imaging practices and to compare those practices to the best available evidence. Patients and Methods A survey was distributed to attending-level surgeons at a regional hand and upper-extremity surgery conference in the United States in 2013. 40 out of 75 surgeons completed the survey (53%). Results All results are presented for distal radius and scaphoid fractures, respectively. There was a high degree of variability between respondents in the number of radiographic series routinely ordered during follow-up of asymptomatic patients, with the number of series ranging from 1–6 and 1–6. On average, respondents did not order an excessive number of follow-up radiographs for asymptomatic patients, with means (± standard deviations) of 2.6 ± 1.0 and 3.3 ± 1.2 radiographic series. Radiographic series were taken at only 74% and 81% of postoperative visits with asymptomatic patients. Only 10% and 8% of respondents felt it was acceptable medical practice to save costs by ordering postoperative radiographs only when patients are symptomatic. Conclusions Among a sample of 40 fellowship-trained hand surgeons, these findings demonstrate a high degree of variability in number of radiographs obtained after operative repair of distal radius and scaphoid fractures. On average, respondents were relatively efficient with respect to total number of postoperative radiographs ordered. Level of Evidence Diagnostic study, level IV. PMID:25364636

  18. Non-operative treatment versus percutaneous fixation for minimally displaced scaphoid waist fractures in high demand young manual workers.

    PubMed

    Majeed, Haroon

    2014-12-01

    Managing minimally displaced scaphoid fractures in young individuals doing physically demanding work remains an issue of debate due to duration of immobilisation and time required off work. Therefore, early diagnosis and appropriate treatment are important to avoid short- and long-term consequences. The literature lacks the exact definition of minimally displaced scaphoid waist fractures. The objective of this review article was to discuss nonoperative and minimally invasive treatment (percutaneous screw fixation) for minimally displaced scaphoid waist fractures and to systematically review the literature, focussing on young workers with physically demanding employment. We searched for articles through the most commonly used portals using appropriate terminologies to identify the most relevant articles in the English language comparing nonoperative and percutaneous fixation methods for these fractures in patients between 16 and 40 years of age. Strict inclusion and exclusion criteria were observed. Sixty relevant published articles were found. Twenty-one of these were considered valid for inclusion and comprised five randomised controlled trials, three prospective studies, four systematic reviews, three meta-analyses, and six retrospective studies. These studies provided a reasonable account of information on the managing undisplaced and minimally displaced scaphoid waist fractures, with satisfactory clinical and statistical analysis. However, it was difficult to assess the outcomes of minimally displaced fractures in isolation. Furthermore, few of these studies relied on plain radiographs for assessing union and did not report on patients' work status. Cast treatment has the disadvantages of longer immobilisation time, joint stiffness, reduced grip strength, and longer time to return to manual work. Percutaneous fixation is aimed at reducing damage to the blood supply and soft tissues, allowing early mobilisation of the wrist and early return to manual work. The

  19. [First results with a resorbable MgYREZr compression screw in unstable scaphoid fractures show extensive bone cysts].

    PubMed

    Meier, Reinhard; Panzica, Martin

    2017-03-08

    Osteosynthesis with headless compression screws is an established treatment option for unstable scaphoid fractures. Common implants are made of titanium alloy or steel and usually remain in place. Due to implant density and ferromagnetic properties, artefacts are common in postoperative imaging procedures, e.g. MRI. Now resorbable implants made of magnesium alloy (MgYREZr) have become available. They have biomechanical properties equivalent to human bone and may be used as an alternative to the nonresorbable screw systems.5 patients with acute scaphoid fractures were treated with a double-threaded screw made of MgYREZr. The fractures included three type A2 fractures, one type B2 fracture, and one type B3 fracture. All patients underwent clinical and radiological follow-up postoperatively, 6 weeks, 3 and 6 months and 1 year after surgery. ROM, gross grip strength and pain (VAS) were documented. The Modified Mayo Wrist Score was used. Standard X-rays of the wrist were taken preoperatively and at all follow-up visits. A CT scan was performed at least before and three months after surgery. In all X-rays malunion, resorption of the implant, implant loosening, cysts and bone healing (bridging trabecular structures) were described.All patients had a very good wrist score (95-100 points) after one year. There were no clinical complications. However, the X-rays revealed extensive resorption cysts in 3 out of the 5 patients. It was only after 6 months that the fractures were consolidated enough to allow physical work. Due to this considerable osteolysis, we did not include any further patients. Due to the observed extensive bone cysts and the long time period for bone healing, MgYREZr compression screws are currently not recommended for clinical use in scaphoid fractures. Further fundamental research is necessary.

  20. Is Casting for Non-Displaced Simple Scaphoid Waist Fracture Effective? A CT Based Assessment of Union

    PubMed Central

    Grewal, Ruby; Suh, Nina; MacDermid, Joy C.

    2016-01-01

    Objective: The purpose of this study is to report the union rate and time to union for acute non-displaced scaphoid waist fractures treated with a short arm thumb spica cast. Methods: A database was searched (2006-2013) to identify acute undisplaced scaphoid waist fractures. Cases that were not given a trial of casting were excluded (n=33). X-rays, CT scans and health records for each patient were reviewed to extract data. Results: 172 patients met inclusion criteria. There were 138 males, 34 females, the mean age was 30 ± 16 years. The union rate was 99.4% (1 nonunion/172 subjects). The mean time to union was approximately 7.5 weeks (53 ± 37 days). Energy of injury, age or gender did not affect union rates or time to union. Cysts did not affect the union rate (p=0.73) but patients with cystic resorption along the fracture line required approximately 10 weeks for union (69 ± 60 days) compared to 7 weeks (51 ± 34 days) for those without cysts (p=0.05). Diabetes did not affect the union rate (p=0.81) but was found to increase the risk of delayed union (p=0.05). There was a weak, but statistically significant correlation between the number of days before the fracture was casted and the length of time needed to achieve union (r=0.27, p=0.001). Conclusion: Non-displaced scaphoid waist fractures have a high healing rate with appropriate identification and immobilization. Follow-up CT scans to assess healing can identify union within a shorter time frame (~7 weeks) than previously reported in the literature. PMID:27708739

  1. Reconstruction of Scaphoid Nonunion Fractures of the Proximal One Third With a Vascularized Bone Graft From the Distal Radius

    PubMed Central

    Jaminet, Patrick; Naegele, Beate; Pfau, Matthias; Schaller, Hans-Eberhard

    2014-01-01

    Objective: The treatment of proximal located scaphoid nonunion is a well-known and common problem. For these patients, we used a vascular pedicled bone graft of the distal radius. Methods: In the last 7 years, 75 patients were treated with the vascular pedicled bone graft. Retrospectively, patients’ data, healing rates, and factors influencing scaphoid healing were analyzed. Results: The overall healing rate in cases with proximal located nonunions (n = 54) was approximately 70%. Out of these 54 patients, 47 patients showed avascular proximal fragments. Multivariate analysis showed no significant impact for the factors age, smoking, duration of disease, or previous operation. Conclusions: In our negative selected patient group, we were able to achieve good results with the usage of a pedicled vascularized bone graft of the distal radius. Our results indicate a favorable outcome for the use of a pedicled vascularized distal radius bone graft in both scaphoid nonunion fractures of the proximal third, with or without an avascular proximal pole. PMID:25165493

  2. The validity of investigating occult hip fractures using multidetector CT

    PubMed Central

    Williams, Huw L M; Carpenter, Eleanor C; Lyons, Kathleen

    2016-01-01

    Objective: 10% of all hip fractures are occult on plain radiography, requiring further investigation to ascertain the diagnosis. MRI is presently the gold standard investigation, but frequently has disadvantages of time delay, resulting in increased hospital stay and mortality. Our aim was to establish whether multidetector CT (MDCT) is an appropriate first-line investigation of occult femoral neck (NOF) fractures. Methods: From 2013, we elected to use MDCT as the first-line investigation in patients believed to have an NOF fracture with negative plain films. These were reported by consultant musculoskeletal radiologists. We retrospectively analysed the data of consecutive patients presenting to the University Hospital of Wales, over 30 months with a clinical suspicion of a hip fracture. Results: 1443 patients were admitted during the study period. 209 (14.5%) patients had negative plain films requiring further investigation to exclude an NOF fracture, of which 199 patients had a CT. 93 patients had no fracture and 20 patients had isolated greater trochanter fractures. None of these patients progressed to develop an intracapsular femoral neck fracture at 4-month follow-up, although one patient sustained an extracapsular fracture following a high-energy fall whilst admitted. 26 femoral neck fractures were diagnosed on CT, whilst the remaining 60 patients were diagnosed with other pelvic ring fractures. Conclusion: When interpreted by experienced radiologists, MDCT has both sensitivity and specificity of 100%. Advances in knowledge: We recommend the use of MDCT as a safe and appropriate first-line investigation for NOF fractures. PMID:26838948

  3. Low-Intensity Pulsed Ultrasound Treatment for Scaphoid Fracture Nonunions in Adolescents

    PubMed Central

    Carlson, Erik J.; Save, Ameya V.; Slade, Joseph F.; Dodds, Seth D.

    2015-01-01

    Background Treatment of scaphoid nonunion is challenging, leading clinicians to pursue innovation in surgical technique and adjunctive therapies to improve union rates. Purpose The purpose of this study was to investigate the use of low-intensity pulsed ultrasound as an adjunctive treatment modality following surgical treatment of scaphoid nonunion in adolescent patients, for whom this therapy has not yet been FDA-approved. Patients and Methods We performed a retrospective review of adolescent patients with scaphoid nonunion treated surgically followed by adjunctive low-intensity pulsed ultrasound therapy. All patients underwent 20 minutes of daily ultrasound therapy postoperatively until there was evidence of bony healing, based on both clinical and radiographic criteria. Final healing was confirmed by > 50% bone bridging on CT scan. Results Thirteen of fourteen (93%) patients healed at a mean interval of 113 days (range 61–217 days). There were no surgical or postoperative complications. One patient developed heterotopic bone formation about the scaphoid. Conclusions Our study suggests that low-intensity pulsed ultrasound therapy can safely be utilized as an adjunctive modality in adolescents to augment scaphoid healing following surgical intervention. Level of Evidence Level IV, Case series PMID:25945296

  4. Radiographically occult and subtle fractures: a pictorial review.

    PubMed

    Jarraya, Mohamed; Hayashi, Daichi; Roemer, Frank W; Crema, Michel D; Diaz, Luis; Conlin, Jane; Marra, Monica D; Jomaah, Nabil; Guermazi, Ali

    2013-01-01

    Radiographically occult and subtle fractures are a diagnostic challenge. They may be divided into (1) "high energy trauma fracture," (2) "fatigue fracture" from cyclical and sustained mechanical stress, and (3) "insufficiency fracture" occurring in weakened bone (e.g., in osteoporosis and postradiotherapy). Independently of the cause, the initial radiographic examination can be negative either because the findings seem normal or are too subtle. Early detection of these fractures is crucial to explain the patient's symptoms and prevent further complications. Advanced imaging tools such as computed tomography, magnetic resonance imaging, and scintigraphy are highly valuable in this context. Our aim is to raise the awareness of radiologists and clinicians in these cases by presenting illustrative cases and a discussion of the relevant literature.

  5. Impact of Different Screw Designs on Durability of Fracture Fixation: In Vitro Study with Cyclic Loading of Scaphoid Bones

    PubMed Central

    Gruszka, Dominik; Herr, Robert; Hely, Hans; Hofmann, Peer; Klitscher, Daniela; Hofmann, Alexander; Rommens, Pol Maria

    2016-01-01

    Purpose The use of new headless compression screws (HCSs) for scaphoid fixation is growing, but the nonunion rate has remained constant. The aim of this study was to compare the stability of fixation resulting from four modern HCSs using a simulated fracture model to determine the optimal screw design(s). Methods We tested 40 fresh-frozen cadaver scaphoids treated with the Acumed Acutrak 2 mini (AA), the KLS Martin HBS2 midi (MH), the Stryker TwinFix (ST) and the Synthes HCS 3.0 with a long thread (SH). The bones with simulated fractures and implanted screws were loaded uniaxially into flexion for 2000 cycles with a constant bending moment of 800 Nmm. The angulation of the fracture fragments was measured continuously. Data were assessed statistically using the univariate ANOVA test and linear regression analysis, and the significance level was set at p < 0.05. Results The median angulation of bone fragments φ allowed by each screw was 0.89° for AA, 1.12° for ST, 1.44° for SH and 2.36° for MH. With regards to linear regression, the most reliable curve was achieved by MH, with a coefficient of determination of R2 = 0.827. This was followed by AA (R2 = 0.354), SH (R2 = 0.247) and ST (R2 = 0.019). Data assessed using an adapted ANOVA model showed no statistically significant difference (p = 0.291) between the screws. Conclusions The continuous development of HCSs has resulted in very comparable implants, and thus, at this time, other factors, such as surgeons’ experience, ease of handling and price, should be taken into consideration. PMID:26741807

  6. [Application of bone flap pedicled on retrograde branch of radial artery for treatment of old scaphoid bone fractures of type AO-B].

    PubMed

    Sun, Qing-peng

    2015-05-01

    To investigate application of the bone flap pedicled on the retrograde branch of radial artery for treatment of old scaphoid bone fractures of type AO-B. From October 2007 to October 2011,41 patients with old scaphoid bone fractures of type AO-B were treated by transplantation of the bone flap pedicled on the retrograde branch of radial artery including 26 males and 15 females with an average of (27.3±4.5) years old ranging from 16 to 43 years old. The courses before operation ranged from 6 to 22 months with an average of 11 months. All fractures belonged to the type B of AO classification, that is old wrist fracture of scaphoid bone. All patients' wrist function (pain, function, motion, grip strength) were evaluated by Cooney's modifiedwrist scoring system before and 6 months after operation,and the conditions of bone healing were observed during the follow-up time. Among them, 36 patients were followed up from 4 to 15 months with an average of 8.3 months. The wounds were healed well without other complications as infection appearing. X-rays or CT confirmed that all fractures were healed completely. The Cooney wrist score was improved from preoperative 53.61±13.97 to postoperative 81.81±8.71 (P<0.01). The operation of transplantation of the bone flap pedicled on the retrograde branch of radial artery is an effective method to treat old scaphoid bone fractures,which is scientific and has curative effects, and valuable for clinical application.

  7. Prevalence and clinical significance of occult fractures in children with radiograph-negative acute ankle injury

    PubMed Central

    Najaf-Zadeh, Abolfazl; Nectoux, Eric; Dubos, François; Happiette, Laurent; Demondion, Xavier; Gnansounou, Magloire; Herbaux, Bernard; Martinot, Alain

    2014-01-01

    Background and purpose Plain radiographs may fail to reveal an ankle fracture in children because of developmental and anatomical characteristics. In this systematic review and meta- analysis, we estimated the prevalence of occult fractures in children with acute ankle injuries and clinical suspicion of fracture, and assessed the diagnostic accuracy of ultrasound (US) in the detection of occult fractures. Methods We searched the literature and included studies reporting the prevalence of occult fractures in children with acute ankle injuries and clinical suspicion of fracture. Proportion meta-analysis was performed to calculate the pooled prevalence of occult fractures. For each individual study exploring the US diagnostic accuracy, we calculated US operating characteristics. Results 9 studies (involving 187 patients) using magnetic resonance imaging (MRI) (n = 5) or late radiographs (n = 4) as reference standard were included, 2 of which also assessed the diagnostic accuracy of US. Out of the 187 children, 41 were found to have an occult fracture. The pooled prevalence of occult fractures was 24% (95% CI: 18–31). The operating characteristics for detection of occult ankle fractures by US ranged in positive likelihood ratio (LR) from 9 to 20, and in negative LR from 0.04 to 0.08. Interpretation A substantial proportion of fractures may be overlooked on plain radiographs in children with acute ankle injuries and clinical suspicion of fracture. US appears to be a promising method for detection of ankle fractures in such children when plain radiographs are negative. PMID:24875057

  8. Treatment of delayed/nonunion of scaphoid waist with Synthes cannulated scaphoid screw and bone graft.

    PubMed

    Inaparthy, P K; Nicholl, J E

    2008-12-01

    Fracture of the scaphoid bone is the most common fracture of the carpus, and frequently, diagnosis is delayed. The unique anatomy and blood supply of the scaphoid itself predisposes to delayed union or nonunion. The Synthes scaphoid screw is a cannulated headed screw, which provides superior compression compared with some other devices used to internally fix scaphoid nonunions. Our aim was to conduct a retrospective study looking at the union rate, time to union, and complications and correlating the outcome of treatment against the delay between injury and surgery and location of the fracture within the bone. This study is a review of a cohort of 30 patients treated with a cannulated Synthes scaphoid screw and corticocancellous bone grafting for scaphoid waist delayed union and nonunion at our center. We achieved 86% overall union rate. The patients with delayed union achieved a 100% union rate. Three out of four patients with persistent nonunion after surgery reported no pain and improved function. The failure rate was 75% in patients who had sustained their fracture more than 5 years previously. Our study demonstrates that delayed union of scaphoid waist fractures and scaphoid waist nonunions present for less than 5 years can be successfully treated by fracture compression and bone grafting.

  9. Treatment of Delayed/Nonunion of Scaphoid Waist with Synthes Cannulated Scaphoid Screw and Bone Graft

    PubMed Central

    Nicholl, J. E.

    2008-01-01

    Fracture of the scaphoid bone is the most common fracture of the carpus, and frequently, diagnosis is delayed. The unique anatomy and blood supply of the scaphoid itself predisposes to delayed union or nonunion. The Synthes scaphoid screw is a cannulated headed screw, which provides superior compression compared with some other devices used to internally fix scaphoid nonunions. Our aim was to conduct a retrospective study looking at the union rate, time to union, and complications and correlating the outcome of treatment against the delay between injury and surgery and location of the fracture within the bone. This study is a review of a cohort of 30 patients treated with a cannulated Synthes scaphoid screw and corticocancellous bone grafting for scaphoid waist delayed union and nonunion at our center. We achieved 86% overall union rate. The patients with delayed union achieved a 100% union rate. Three out of four patients with persistent nonunion after surgery reported no pain and improved function. The failure rate was 75% in patients who had sustained their fracture more than 5 years previously. Our study demonstrates that delayed union of scaphoid waist fractures and scaphoid waist nonunions present for less than 5 years can be successfully treated by fracture compression and bone grafting. PMID:18780015

  10. Occult fractures of the greater tuberosity of the humerus.

    PubMed

    Gumina, S; Carbone, S; Postacchini, F

    2009-02-01

    We studied the highest reported number of patients with occult fracture of the greater tuberosity of the humerus and we analysed why fracture was not diagnosed, shoulder function and prevalence of eventually associated rotator cuff tear (RCT). Twenty-four patients with a missed fracture of the greater tuberosity underwent MR study for a suspect RCT. We evaluated shoulder function and self-assessed comfort with the Constant score (CS) and Simple Shoulder Test (SST). Nine patients showed evidence of cuff tendinosis, 11 of partial (p) RCT (2: subscapularis; 6: supraspinatus and 3: supraspinatus and infraspinatus). All patients with pRCT were older than 40. Initially, the mean CS and SST were 54% and 5/12; at follow-up, values increased to 36% and 5 points. MR should be performed in patients apparently negative for fracture but with painful shoulders and decreased ROM. Of our patients, 45.8% had pRCT; nevertheless function recovery was verified in 16 weeks.

  11. Periprosthetic Occult Fractures of the Acetabulum Occur Frequently During Primary THA.

    PubMed

    Hasegawa, Kazuhiro; Kabata, Tamon; Kajino, Yoshitomo; Inoue, Daisuke; Tsuchiya, Hiroyuki

    2017-02-01

    Periprosthetic fractures of the acetabulum occurring during primary THA are rare. Periprosthetic occult fractures are defined as those not identified by the surgeon during the procedure which might be missed on a routine postoperative radiograph. However, it is unclear how frequently these fractures occur and whether their presence affects functional recovery. In this study, using routine CT scans that were obtained as part of another primary hip arthroplasty study protocol, we retrospectively assessed (1) the prevalence of occult fractures of the acetabulum occurring during primary THA, (2) the location of occult fractures of the acetabulum during THA, and (3) risk factors contributing to such occult fractures. Between 2004 and 2013, our institute performed 585 primary THAs (cementless or hybrid) in 494 patients with DICOM pre- and postoperative CT; during the period in question, all patients undergoing THA underwent CT before and after surgery. Preoperative CT images were taken as part of a CT-based three-dimensional templating software and navigation system. Postoperative CT images were taken an average of 1 week after surgery as part of a different protocol to evaluate cup position, restoration of leg length and offset, volume of postoperative hematoma to assess anticoagulation effects after THA, and fractures that were not found on routine postoperative radiographs (which we defined as occult fractures). Patients with a history of prior pelvic osteotomy, trauma, and infection were excluded (88 patients/99 hips); 406 patients (102 males and 304 females; 486 hips) form the basis of this report. The mean age of the patients was 60 ± 11 years, with a mean BMI of 23 ± 4 kg/m(2). The mean followup of the patients with periprosthetic fracture of the acetabulum was 58 ± 28 months (range, 12-131 months). Potential risk factors for occult acetabular fracture including age, sex, BMI, preoperative diagnosis, additional dome screw fixation, composition and size of each

  12. Prevalence of exclusively and concomitant pelvic fractures at magnetic resonance imaging of suspect and occult hip fractures.

    PubMed

    Collin, David; Geijer, Mats; Göthlin, Jan H

    2016-02-01

    Pelvic fractures may occur together with hip fractures as a result of low energy trauma. It is unclear whether they do require special attention. There are conflicting results in the literature about the prevalence of both concomitant hip and pelvic fractures as well as exclusive pelvic fractures. It has been reported that hip fractures and obturator ring fractures are mutually exclusive. To retrospectively analyze the prevalence of exclusively pelvic as well as concomitant hip and pelvic fractures in patients examined with MRI after low-energy trauma in elderly. During 9 years, 316 elderly patients had been examined with MRI for suspected or occult hip fracture after a fall. A fracture was diagnosed when MRI showed focal signal abnormalities in the subcortical bone marrow, with or without disruption of adjacent cortices. One observer reviewed all studies. A second observer verified all studies with hip fractures. Follow-up was available for all but two patients that died prior to hip surgery. The prevalence of concomitant pelvic and femoral neck or trochanteric fractures was statistically compared using chi-squared test for categorical variables. Hip fractures were found in 161 (51 %) patients of which 29 (9 %) had concomitant pelvic fractures. There were exclusively pelvic fractures in 82 (26 %) patients of which 65 (79 %) were on the traumatized side only. In 73 patients, there were no fractures. Occult or suspected hip fractures are not infrequently associated with pelvic fractures. Exclusively pelvic fractures are not uncommon.

  13. Metallic artifacts from internal scaphoid fracture fixation screws: comparison between C-arm flat-panel, cone-beam, and multidetector computed tomography.

    PubMed

    Finkenstaedt, Tim; Morsbach, Fabian; Calcagni, Maurizio; Vich, Magdalena; Pfirrmann, Christian W A; Alkadhi, Hatem; Runge, Val M; Andreisek, Gustav; Guggenberger, Roman

    2014-08-01

    The aim of this study was to compare image quality and extent of artifacts from scaphoid fracture fixation screws using different computed tomography (CT) modalities and radiation dose protocols. Imaging of 6 cadaveric wrists with artificial scaphoid fractures and different fixation screws was performed in 2 screw positions (45° and 90° orientation in relation to the x/y-axis) using multidetector CT (MDCT) and 2 flat-panel CT modalities, C-arm flat-panel CT (FPCT) and cone-beam CT (CBCT), the latter 2 with low and standard radiation dose protocols. Mean cartilage attenuation and metal artifact-induced absolute Hounsfield unit changes (= artifact extent) were measured. Two independent radiologists evaluated different image quality criteria using a 5-point Likert-scale. Interreader agreements (Cohen κ) were calculated. Mean absolute Hounsfield unit changes and quality ratings were compared using Friedman and Wilcoxon signed-rank tests. Artifact extent was significantly smaller for MDCT and standard-dose FPCT compared with CBCT low- and standard-dose acquisitions (all P < 0.05). No significant differences in artifact extent among different screw types and scanning positions were noted (P > 0.05). Both MDCT and FPCT standard-dose protocols showed equal ratings for screw bone interface, fracture line, and trabecular bone evaluation (P = 0.06, 0.2, and 0.2, respectively) and performed significantly better than FPCT low- and CBCT low- and standard-dose acquisitions (all P < 0.05). Good interreader agreement was found for image quality comparisons (Cohen κ = 0.76-0.78). Both MDCT and FPCT standard-dose acquisition showed comparatively less metal-induced artifacts and better overall image quality compared with FPCT low-dose and both CBCT acquisitions. Flat-panel CT may provide sufficient image quality to serve as a versatile CT alternative for postoperative imaging of internally fixated wrist fractures.

  14. Computer-Assisted 3-Dimensional Reconstructions of Scaphoid Fractures and Nonunions With and Without the Use of Patient-Specific Guides: Early Clinical Outcomes and Postoperative Assessments of Reconstruction Accuracy.

    PubMed

    Schweizer, Andreas; Mauler, Flavien; Vlachopoulos, Lazaros; Nagy, Ladislav; Fürnstahl, Philipp

    2016-01-01

    To present results regarding the accuracy of the reduction of surgically reconstructed scaphoid nonunions or fractures using 3-dimensional computer-based planning with and without patient-specific guides. Computer-based surgical planning was performed with computed tomography (CT) data on 22 patients comparing models of the pathological and the opposite uninjured scaphoid in 3 dimensions. For group 1 (9 patients), patient-specific guides were designed and manufactured using additive manufacturing technology. During surgery, the guides were used to define the orientation of the reduced fragments. The scaphoids in group 2 (13 patients) were reduced with the conventional freehand technique. All scaphoids in both groups were fixed with a headless compression screw or K-wires, and all bone defects (except one) were filled with autologous bone grafts or vascularized grafts. Postoperative CT scans were acquired 2 or more months after the operations to monitor consolidation and compare the final result with the preoperative plan. The clinical results and accuracy of the reconstructions were compared. In group 1, 8 of 9 scaphoids healed after 2 to 6 months, and partial nonunion after 9 months was observed in one patient. In group 2, 11 of 13 scaphoids healed between 2 and 34 months whereas 2 scaphoids did not consolidate. Comparison of the preoperative and postoperative 3-dimensional data revealed an average residual displacement of 7° (4° in flexion-extension, 4° in ulnar-radial deviation, and 3° in pronation-supination) in group 1. In group 2, residual displacement after surgery was 26° (22° in flexion-extension, 12° in ulnar-radial deviation, and 7° in pronation-supination). The difference in the accuracy of reconstruction was significant. Although the scaphoid is small, patient-specific guides can be used to perform scaphoid reconstructions. When the guides were used, the reconstructions were significantly more anatomic compared with those resulting from the

  15. Occult spinous process fractures associated with interspinous process spacers.

    PubMed

    Kim, David H; Tantorski, Mark; Shaw, Jeremy; Martha, Juli; Li, Ling; Shanti, Nael; Rencu, Tal; Parazin, Stephen; Kwon, Brian

    2011-07-15

    Prospective observational study. To provide a more accurate estimate of the rate of acute spinous process fractures associated with IPS surgery. Biomechanical cadaveric studies have suggested adequate spinous process strength to support placement of interspinous process spacers (IPS). Postoperative spinous process fractures have been reported in one%-to 5.8% of patients in previous series based on routine biplanar radiographic evaluation. However, most fractures occur between the base and midportion of the spinous process in an area that is typically difficult to visualize on plain radiographs due to device design. All patients underwent preoperative biplanar plain radiographs and computed tomography (CT) of the lumbar spine to confirm anatomy favorable for IPS placement and rule out fracture or spondylolysis. Postoperatively, all patients underwent repeat CT imaging within six months of surgery, biplanar radiographs at two weeks, six weeks, three months, six months, and one year. All studies were reviewed independently by a neuroradiologist and two orthopedic spine surgeons. Fifty implants (38 L4-5, 12 L3-4) were placed in 38 patients who completed follow-up and were included in final analysis. Three IPS designs were included (34 Medtronic X-STOP titanium, 8 X-STOP PEEK, 8 Lanx Aspen). Postoperative CT revealed 11 nondisplaced spinous process fractures in 11 patients (28.9% of patients, 22% of levels). Five fractures were associated with mild to moderate lumbar back pain and six fractures were asymptomatic. No patient reported a traumatic incident. No fracture was identifiable on plain radiographs. One fracture displaced during follow-up evaluation. Three patients underwent IPS removal and laminectomy. Three fractures healed by CT in one year. Overall, patients with fractures tended toward poorer outcomes by Zurich Claudication Questionnaire (ZCQ) (28.5% vs. 34.8% improvement in symptom severity, P = 0.496; 21.4% vs. 30.7% improvement in physical function, P = 0

  16. Review article: Magnetic resonance imaging and computed tomography in the diagnosis of occult proximal femur fractures.

    PubMed

    Chatha, Hamid A; Ullah, Sana; Cheema, Zulfiqar Z

    2011-04-01

    Electronic databases of MEDLINE, EMBASE, CINAHL, and the Cochrane Library as well as the Google Scholar search engine were used. Studies written in the English language highlighting the use of magnetic resonance imaging (MRI) and computed tomography in diagnosing occult proximal femoral fractures despite negative or equivocal plain radiographs were included. Two reviewers independently extracted data from each article. Raw frequencies for each of the details investigated were calculated. 15 prospective and 7 retrospective studies from 1989 to 2009 were included in this systematic review. A total of 996 patients (mean age, 75 years; standard deviation, 5 years) with suspected occult proximal femur fractures underwent MRI for further assessment. 350 (35%) of the patients tested positive for proximal femoral fractures, of whom 295 (84%) underwent further treatment/surgical interventions. MRI also detected other fractures and soft-tissue injuries. MRI was superior to other imaging modalities in diagnosing occult proximal femoral fractures and should be performed within 24 hours of injury. Early diagnosis and management may avoid substantial displacement and complications, and improve overall mortality and morbidity.

  17. Absorbable scaphoid screw development: a comparative study on biomechanics

    PubMed Central

    Wang, Yi; Song, Muguo; Xu, Yongqing; He, Xiaoqing; Zhu, YueLiang

    2016-01-01

    Background The scaphoid is critical for maintaining the stability and movement of the wrist joints. This study aimed to develop a new internal fixator absorbable scaphoid screw (ASS) for fixation of the scaphoid waist after fracture and to test the biomechanical characteristics of ASS. Materials and methods An ASS was prepared using polylactic acids and designed based on scaphoid measurements and anatomic features. Twenty fractured scaphoid waist specimens were randomly divided into experimental and control groups (n=10/group). Reduction and internal fixation of the scaphoid were achieved with either Kirschner wires (K-wires) or ASS. A moving target simulator was used to test palmar flexion and dorsal extension, with the range of testing (waist movement) set from 5° of palmar flexion to 25° of dorsal extension. Flexion and extension were repeated 2,000 times for each specimen. Fracture gap displacements were measured with a computerized tomography scanning. Scaphoid tensile and bending strengths were measured by using a hydraulic pressure biomechanical system. Results Prior to biomechanical fatigue testing, fracture gap displacements were 0.16±0.02 mm and 0.22±0.02 mm in the ASS and K-wire groups, respectively. After fatigue testing, fracture gap displacements in the ASS and the K-wire groups were 0.21±0.03 mm and 1.52±0.07 mm, respectively. The tensile strengths for the ASS and K-wire groups were 0.95±0.02 MPa and 0.63±0.02 MPa, respectively. Conclusion Fixation using an ASS provided sufficient mechanical support for the scaphoid after fracture. PMID:27217756

  18. Sonography of occult rib and costal cartilage fractures: a case series.

    PubMed

    Mattox, Ross; Reckelhoff, Kenneth E; Welk, Aaron B; Kettner, Norman W

    2014-06-01

    The purpose of this case series is to describe the use of diagnostic ultrasound (US) in the detection of occult rib and costal cartilage fractures presenting as chest wall pain to a chiropractic clinic. Three patients presented with chest wall pain and tenderness. Two of the patients presented with acute chest wall injury and 1 carried a previous diagnosis of rib fracture after trivial trauma 2 months earlier. Diagnostic US was selected as a non-ionizing imaging tool for these patients after negative digital radiography studies. All fractures were considered isolated as there was no associated injury, such as pneumothorax. Both of the acute cases were followed up to complete healing (evidence of osseous union) using US. All patients eventually achieved pain-free status. In these cases, US was more sensitive than radiography for diagnosing these cases of acute rib and costal cartilage fractures. Early recognition of rib injury could avoid potential complications from local manipulative therapy.

  19. FDG-PET uptake in occult acute pelvic fracture.

    PubMed

    Ravenel, James G; Gordon, Leonie L; Pope, Thomas L; Reed, Carolyn E

    2004-02-01

    The role of FDG-PET in the diagnosis of bone metastases remains unsettled, although it is hoped that PET scans will add specificity to or replace bone scintigraphy. We report a case in which an acute traumatic fracture presented with a level of uptake generally considered indicative of neoplasm. It is important to recognize that increased FDG-PET activity in bone should not be accepted as definitive evidence of metastatic disease.

  20. Neglected isolated scaphoid dislocation

    PubMed Central

    Baek, Jong-Ryoon; Cho, Seung Hyun; Lee, Yong Seuk; Roh, Young Hak

    2016-01-01

    The authors present a case of isolated scaphoid dislocation in a 40-year-old male that was undiagnosed for 2 months. The patient was treated by open reduction, Kirschner wire fixation, interosseous ligament repair using a suture anchor and Blatt's dorsal capsulodesis. At 6 years followup, his radiographs of wrist showed a normal carpal alignment with a scapholunate gap of 3 mm and no evidence of avascular necrosis (AVN) of the scaphoid. PMID:27904228

  1. Radiograph-Negative Lateral Ankle Injuries in Children: Occult Growth Plate Fracture or Sprain?

    PubMed

    Boutis, Kathy; Plint, Amy; Stimec, Jennifer; Miller, Elka; Babyn, Paul; Schuh, Suzanne; Brison, Robert; Lawton, Louis; Narayanan, Unni G

    2016-01-01

    Lateral ankle injuries without radiographic evidence of a fracture are a common pediatric injury. These children are often presumed to have a Salter-Harris type I fracture of the distal fibula (SH1DF) and managed with immobilization and orthopedic follow-up. However, previous small studies suggest that these injuries may represent ankle sprains rather than growth plate fractures. To determine the frequency of SH1DF using magnetic resonance imaging (MRI) and compare the functional recovery of children with fractures identified by MRI vs those with isolated ligament injuries. A prospective cohort study was conducted between September 2012 and August 2014 at 2 tertiary care pediatric emergency departments. We screened 271 skeletally immature children aged 5 to 12 years with a clinically suspected SH1DF; 170 were eligible and 140 consented to participate. Children underwent MRI of both ankles within 1 week of injury. Children were managed with a removable brace and allowed to return to activities as tolerated. The proportion with MRI-confirmed SH1DF. A secondary outcome included the Activity Scale for Kids score at 1 month. Of the 135 children who underwent ankle MRI, 4 (3.0%; 95% CI, 0.1%-5.9%) demonstrated MRI-confirmed SH1DF, and 2 of these were partial growth plate injuries. Also, 108 children (80.0%) had ligament injuries and 27 (22.0%) had isolated bone contusions. Of the 108 ligament injuries, 73 (67.6%) were intermediate to high-grade injuries, 38 of which were associated with radiographically occult fibular avulsion fractures. At 1 month, the mean (SD) Activity Scale for Kids score of children with MRI-detected fibular fractures (82.0% [17.2%]) was not significantly different from those without fractures (85.8% [12.5%]) (mean difference, -3.8%; 95% CI, -1.7% to 9.2%). Salter-Harris I fractures of the distal fibula are rare in children with radiograph fracture-negative lateral ankle injuries. These children most commonly have ligament injuries (sprains

  2. The effects of Scaphoid and Colles casts on hand function.

    PubMed

    Karantana, A; Downs-Wheeler, M J; Webb, K; Pearce, C A; Johnson, A; Bannister, G C

    2006-08-01

    Although necessary for bone healing, immobilisation temporarily prevents hand function and may necessitate corrective physiotherapy later. Scaphoid and Colles casts are both commonly used to immobilize scaphoid fractures. Non-union rates are comparable with both casts. The Scaphoid cast incorporates the thumb, whereas the Colles cast leaves the thumb free. We compared the effect of the two casts on hand function in 20 healthy right-hand-dominant volunteers using the Jebsen-Taylor Hand Function Test. Data were obtained through a mixed between and within subject design. Both casts prolonged the time taken to complete the hand function test compared to controls. Testing in the Scaphoid cast took significantly longer than in the Colles cast.

  3. Dorsal transscaphoid-transtriquetral perilunate dislocation in pseudarthrosis of the scaphoid.

    PubMed

    Alt, V; Sicre, G

    2004-09-01

    A patient reported that he sustained a minor fall on the outstretched hand in hyperextension, pronation, and in ulnar deviation. Initial radiographs suggested dorsal transscaphoid-transtriquetral perilunate dislocation. Traditionally, however, this injury is the result of a high-energy impact. A CT scan obtained after closed reduction of the dislocation revealed not only a fresh fracture of the triquetrum but also two corticalized fragments of the scaphoid. A former major fall on this hand and a normal scaphoid of the other hand made pseudarthrosis more likely than scaphoid bipartition. Arthrography revealed intact lunotriquetral and scapholunate ligaments, precluding the possibility of preexisting ligamentous instability. Pseudarthrosis of the scaphoid with a loss of scaphoid function as a mechanical tie-rod of the carpus is most likely responsible for this complex injury. This is the first clinical study that shows that single scaphoid discontinuity without preexisting ligamentous carpal instability may lead to complex perilunar dislocation in minor trauma.

  4. Avascular necrosis of the scaphoid after three-ligament tenodesis for scapholunate dissociation: case report.

    PubMed

    De Smet, Luc; Sciot, Raf; Degreef, Ilse

    2011-04-01

    An unusual complication after tenodesis for scapholunate instability (Brunelli's technique) is described. More than 1 year after the procedure, a fracture of the scaphoid with collapse was observed. Further examination concluded there was avascular necrosis of the scaphoid. The patient was treated with a proximal row carpectomy.

  5. Occult posterolateral rotatory dislocation of the elbow with olecranon fracture in a child: a case report

    PubMed Central

    2012-01-01

    Introduction Acute posterolateral rotator elbow dislocation in a child is rare and can be easily misdiagnosed due to immaturity of the epiphysis. This is the first case of occult posterolateral rotator elbow dislocation in combination with an olecranon fracture. We report our experience with this case, which was not diagnosed correctly by plain radiographs. Case presentation An 11-year-old Asian boy suffered severe pain and swelling of his right elbow after his outstretched arm hit a car dashboard in a motor vehicle accident. Plain radiographs showed only a minimally displaced olecranon fracture and a tiny lateral epicondylar avulsion fracture. However, stress radiographs under general anesthesia revealed severe posterolateral rotatory instability. During surgery, we found that the cartilaginous lateral epicondylar apophysis was much larger than the epicondylar fragment on the radiographs. After the lateral epicondylar osteochondral fragment and lateral collateral ligament complex were fixed, the instability disappeared. Conclusion Our experience with this case shows that it is important to check for instability with pediatric elbow fractures, because a tiny avulsion fracture was able to cause severe posterolateral rotatory instability in a child. PMID:22943424

  6. Computed tomography compared to magnetic resonance imaging in occult or suspect hip fractures. A retrospective study in 44 patients.

    PubMed

    Collin, David; Geijer, Mats; Göthlin, Jan H

    2016-11-01

    Computed tomography (CT) for evaluation of occult and suspect hip fractures has been proposed as a good second-line investigation. The diagnostic precision compared to magnetic resonance imaging (MRI) is unclear. To compare the diagnostic performance of CT and MRI in a retrospective study on patients with suspect and occult hip fractures. Forty-four elderly consecutive patients with low-energy trauma to the hip were identified where negative or suspect CT was followed by MRI. Primary reporting and review by two observers as well as the diagnostic performance of the two modalities were compared. Surgical treatment and clinical course were used as outcomes. Compared to the primary reports, the CT reviewers found fewer normal and no suspect cases. MRI changed the primary diagnoses in 27 cases, and in 14 and 15 cases, respectively, at review. There was no disagreement on MRI diagnoses. In our patient population, MRI was deemed a more reliable modality for hip fracture diagnosis in comparison to CT. For clinical decision making, MRI seems to have a higher accuracy than CT. A negative CT finding cannot completely rule out a hip fracture in patients where clinical findings of hip fracture persevere. • Experience is highly influential in diagnosing occult or suspect hip fractures at CT • Inconclusive hip CT shows high inter-rater reliability at experienced review • There was low diagnostic accuracy via CT compared to MRI for all interpreters • Hip fractures can readily be diagnosed at MRI regardless of radiological experience.

  7. Sonography of Occult Rib and Costal Cartilage Fractures: A Case Series

    PubMed Central

    Mattox, Ross; Reckelhoff, Kenneth E.; Welk, Aaron B.; Kettner, Norman W.

    2014-01-01

    Objective The purpose of this case series is to describe the use of diagnostic ultrasound (US) in the detection of occult rib and costal cartilage fractures presenting as chest wall pain to a chiropractic clinic. Clinical features Three patients presented with chest wall pain and tenderness. Two of the patients presented with acute chest wall injury and 1 carried a previous diagnosis of rib fracture after trivial trauma 2 months earlier. Intervention and outcomes Diagnostic US was selected as a non-ionizing imaging tool for these patients after negative digital radiography studies. All fractures were considered isolated as there was no associated injury, such as pneumothorax. Both of the acute cases were followed up to complete healing (evidence of osseous union) using US. All patients eventually achieved pain-free status. Conclusion In these cases, US was more sensitive than radiography for diagnosing these cases of acute rib and costal cartilage fractures. Early recognition of rib injury could avoid potential complications from local manipulative therapy. PMID:25685124

  8. Added value of interpreter experience in occult and suspect hip fractures: a retrospective analysis of 254 patients.

    PubMed

    Collin, David; Göthlin, Jan H; Nilsson, Martin; Hellström, Mikael; Geijer, Mats

    2016-06-01

    The influence of experience in categorizing suspect and occult fractures on radiography compared to MRI and clinical outcome has not been studied. The aim of this study is to evaluate the importance of experience in diagnosing normal or suspect hip radiographs compared to MRI. Primarily reported normal or suspect radiography in 254 patients with low-energy hip trauma and subsequent MRI was re-evaluated by two experienced reviewers. Primary readings and review were compared. The prevalence of fractures among normal and suspect radiographic studies was assessed. Clinical outcome was used as reference. At review of radiography, 44 fractures (17 %) were found. Significantly more fractures were found among suspect cases than among normal cases. At MRI, all 44 fractures were confirmed, and further 64 fractures were detected (25 %). MRI detected all fractures with no missed fractures revealed at follow-up. There were a significantly higher proportion of fractures at MRI among the suspect radiographic diagnoses for both the primary report and at review than among occult cases. The more experienced reviewers classified radiography examinations with higher accuracy than primary reporting general radiologists. There was almost complete agreement on MRI diagnoses.

  9. PSEUDARTHROSIS OF THE SCAPHOID IN IMMATURE SKELETONS

    PubMed Central

    de Lemos, Marcelo Barreto; Bentes, Ádria Simone Ferreira; Neto, Miguel Flores do Amaral; Spinelli, Leandro de Freitas; Severo, Antônio Lourenço; Lech, Osvandré

    2015-01-01

    This paper presents a review of the literature on pseudarthrosis of the scaphoid in skeletally immature individuals, taking into consideration its epidemiology, diagnosis and treatment, as well as its controversies. Knowledge of this subject makes it possible for patients to be given appropriate treatment immediately. Pseudarthrosis of the scaphoid in skeletally immature patients is a rare condition that results from error or lack of diagnosis of a fracture. Thus, careful clinical and radiographic examination should be performed in order to confirm or rule out this diagnosis. Several treatment methods have been reported and have shown good results. These include conservative plaster cast treatment, bone graft without osteosynthesis, bone graft with Kirschner wires, percutaneous screws and bone graft with compression screws. The treatment performed depends on the characteristics of the pseudarthrosis and the surgeon's experience. PMID:27042636

  10. Ultrasound Diagnosis of Either an Occult or Missed Fracture of an Extremity in Pediatric-Aged Children

    PubMed Central

    Lee, Sung-Moon; Lee, Young-Hwan; Suh, Kyung-Jin

    2010-01-01

    Objective To report and assess the usefulness of ultrasound (US) findings for occult fractures of growing bones. Materials and Methods For six years, US scans were performed in children younger than 15 years who were referred with trauma-related local pain and swelling of the extremities. As a routine US examination, the soft tissue, bones, and adjacent joints were examined in the area of discomfort, in addition to the asymptomatic contralateral extremity for comparison. Twenty-five occult fractures in 25 children (age range, five months-15 years; average age, 7.7 years) were confirmed by initial and follow-up radiograms, additional imaging studies, and clinical observation longer than three weeks. Results The most common site of occult fractures was the elbow (n = 9, 36%), followed by the knee (n = 7, 28%), ischium (n = 4, 16%), distal fibula (n = 3, 12%), proximal femur (n = 1, 4%), and humeral shaft (n = 1, 4%). On the retrograde review of the routine radiographs, 13 out of the 25 cases showed no bone abnormalities except for various soft tissue swelling. For the US findings, cortical discontinuity (direct sign of a fracture) was clearly visualized in 23 cases (92%) and was questionable in two (8%). As auxiliary US findings (indirect signs of a fracture), step-off deformities, tiny avulsed bone fragments, double-line appearance of cortical margins, and diffuse irregularity of the bone surfaces were identified. Conclusion Performing US for soft tissue and bone surfaces with pain and swelling, with or without trauma history in the extremities, is important for diagnosing occult or missed fractures of immature bones in pediatric-aged children. PMID:20046499

  11. "Occult" rib fractures diagnosed on computed tomography scan only are still a risk factor for solid organ injury.

    PubMed

    Bhattacharya, Bishwajit; Fieber, Jennifer; Schuster, Kevin; Davis, Kimberly; Maung, Adrian

    2015-01-01

    Prior to the widespread use of computed tomography (CT) scan imaging, lower rib fractures diagnosed on chest X-rays (CXRs) were considered a risk factor for abdominal solid organ injury (ASOI). However, CXRs miss about 50% of the rib fractures that are detected on CT scans. We hypothesized that these "occult" rib fractures would not be predictive for ASOI. Retrospective review of a level I trauma center's database identified all adult blunt trauma patients (n = 11,170) over a 5-year period. Data were abstracted for demographics, injury severity score, presence of ASOI, extremity, pelvic and spine fractures as well as presence and location of rib fractures. Rib fractures correlated with the presence of ASOI, regardless of whether they were diagnosed by CXR or CT scan alone (P < 0.01). Middle (3-7) and lower (8-12) rib fractures, especially, correlated with the presence of ipsilateral ASOI (P < 0.0001). Although CT scan detects more rib fractures than CXR, rib fractures remain a marker for increased likelihood of ASOI regardless of the modality by which they are diagnosed. Patients with rib fractures also have a greater incidence of spine and pelvic fractures. As the trauma community debates moving away from routine whole-body CT imaging towards a more selective approach, these results suggest that any clinical suspicion of rib fractures, despite a negative CXR, may warrant further investigation.

  12. A three-dimensional laminated paper model of the scaphoid from computed tomography.

    PubMed

    Kakizawa, H; Toyota, N; Akiyama, Y; Kijima, Y; Ishida, O; Ito, K

    2007-02-01

    To describe a method of producing a life-sized three-dimensional (3D) solid model of a scaphoid bone by combining multidetector-row computed tomography (MDCT) volume data and rapid prototyping technique using thin paper as material, and to evaluate the dimensional accuracy of the experimental model. We experimentally produced life-sized 3D solid models of 14 cadavers' scaphoid bones using high-resolution MDCT volume data, and evaluated the dimensional accuracy of the 3D solid models. The 3D solid model was almost perfectly produced in both size and shape (length, height, width, dorsal cortical angle, and landmarks of the scaphoid bone) compared to the real cadaver's scaphoid bone. In addition to accuracy, the cost and time for creating the model might be reasonable. This technique may be useful in assisting repair of scaphoid bone fracture.

  13. Calcaneo-Scaphoid Coalition.

    PubMed

    Seddon, H J

    1933-02-01

    Calcaneo-scaphoid coalition occurs in a number of forms, having one feature in common, namely, a skeletal abnormality of the calcaneo-scaphoid gap. The condition is congenital, but nothing is known of its causation. Ranking at first as merely an anatomical curiosity, it was later recognized to be frequently associated with spasmodic flat-foot. Probably 25% of all cases of spasmodic flat-foot show this skeletal anomaly in some form or other.Clinically, this variety of spasmodic flat-foot is indistinguishable from the better-known condition in which the bones are apparently normal. Diagnosis made radiographically; essential that an oblique lateral view of the foot should be taken.Causal relation of the condition to peroneal spasm.All the usual forms of treatment employed for the relief of spasmodic flat-foot fail when a calcaneo-scaphoid coalition is present. Resection of the offending bar is of no proven value, but may be worth further trial. If symptoms persist, subastragaloid arthrodesis is necessary.

  14. Anthropometry of the Human Scaphoid Waist by Three-Dimensional Computed Tomography.

    PubMed

    Smith, Jennifer; Hofmeister, Eric P; Renninger, Christopher; Kroonen, Leo T

    2015-01-01

    Published measurements for the scaphoid are scarce. The purpose of this study is to define anthropometric norms for the waist of the scaphoid to assist in optimizing bone graft quantity and implant use. Computed tomography images of the wrist were reviewed by three surgeons. Anthropometric data were gathered, including the scaphoid waist diameter in two dimensions and the scaphoid waist volume. Each study was measured twice, allowing for determination of inter- and intraobserver reliability. Forty-three studies were examined (23 female and 20 male). Average measurements of the scaphoid waist were 11.28 ± 0.26 mm in the sagittal plane and 8.70 ± 0.17 mm in the coronal plane, and the waist volume was 715 ± 33.0 mm3. Specific measures of the narrowest portion of the scaphoid are provided by this study. Measurements of the scaphoid waist through the use of three-dimensional imaging are an accurate method with good inter- and intraobserver reliability. The measurements obtained from this study can be applied to guide graft and implant selection for treatment of scaphoid waist fractures and nonunions.

  15. Idiopathic avascular necrosis of the scaphoid. A case report.

    PubMed

    Martini, G; Valenti, R; Giovani, S; Nuti, R

    1995-06-01

    Avascular necrosis of the carpal scaphoid is a common disorder after a trauma, i.e. a fracture or mild and repetitive injury. Sometime it can be associated with a systemic disease or chronic steroid intake. Rarely avascular necrosis is found in the absence of a known etiology and so termed "idiopathic". We report a case of idiopathic avascular necrosis of the scaphoid. A painful wrist of six months' duration was observed in a 62-year-old housewife. No history of trauma or steroid administration could be elicited. X-ray showed an osteolytic area with irregular edges surrounded by a ring of osteosclerosis at the proximal pole of the left scaphoid. This datum was confirmed by the magnetic resonance imaging.

  16. Transcapho perilunate dislocation with palmar extrusion of the scaphoid proximal pole.

    PubMed

    Marcuzzi, Augusto; Leigheb, Massimiliano

    2016-04-15

    Perilunate fracture-dislocations usually combine ligament ruptures, bone avulsions, and fractures in different patterns. Rarely a displaced fracture of the scaphoid can coexist with a scapho-lunate dissociation and can result in enucleation of the proximal pole. We report about a case of trans-scaphoid perilunate dislocation with palmar extrusion/enucleation of the scaphoid proximal pole, treated with scaphoid fracture open reduction and internal fixation with screw, scapho-lunate ligament repair with an anchor and vascularization of the scaphoid proximal pole with the 2nd intermetacarpal artery. At 52 months follow up we had good clinical and radiographic results. In conclusion, scientific literature including our experience about this rare complex lesion of the wrist is too weak to support an effective strategy of management but we think that the careful analysis of the single problems can be the key to solve the complexity. Goal of the treatment should be complete revascularization and healing of the scaphoid, avoiding non union and avascular necrosis; simultaneously a proper ligament reconstruction is fundamental to re-establish carpal stability. Prevention of carpal collapse for a SNAC o SLAC situation is essential to reach a good level of Quality of Life and satisfaction of the patient.

  17. The fat pad sign following elbow trauma in adults: its usefulness and reliability in suspecting occult fracture.

    PubMed

    O'Dwyer, Helena; O'Sullivan, Paul; Fitzgerald, Desmond; Lee, Michael J; McGrath, Frank; Logan, P Mark

    2004-01-01

    An elbow joint effusion with no fracture seen on radiographs after acute trauma has become synonymous with occult fracture. This study evaluates the incidence of fracture in such cases as determined by MR imaging and the predictive value of an elbow joint effusion. Twenty consecutive patients whose posttrauma elbow radiographs showed an effusion but no fracture and who were suitable for MR imaging were recruited. The elbow effusion size, represented by anterior and posterior fat pad displacement, was measured from the initial lateral elbow radiograph. Suitable candidates underwent MR imaging using a bone marrow sensitive sequence. The time between injury and MR imaging ranged from 0 to 12 days (mean 4 days). Seventy-five percent of the 20 patients who underwent MR imaging had radiographically occult fractures identified. Some (86.6%) of these fractures were located in the radial head, 6.7% were in the lateral epicondyle, and 6.7% were in the olecranon. Ninety percent had evidence of bone marrow edema. Fifteen percent had collateral ligament disruption identified on MR imaging, and 5% had a loose body. There was no change in patient management as a result of the additional imaging. The anterior fat pad displacement ranged from 5 to 15 mm (mean 9.25), and the posterior fat pad was elevated from 1 to 6 mm (mean 3.2). Our data using MR imaging suggests that fat pad elevation in the presence of recent trauma is frequently associated with a fracture. The size of the effusion, anterior/posterior fat pad elevation, or a combination of both does not correspond to the likelihood of an underlying fracture. MR imaging reveals a broad spectrum of bone and soft tissue injury beyond that recognizable on plain radiographs as demonstrated by all patients in this study.

  18. A comparison of fixation screws for the scaphoid during application of cyclical bending loads.

    PubMed

    Toby, E B; Butler, T E; McCormack, T J; Jayaraman, G

    1997-08-01

    Matched pairs of scaphoids from cadavera were stressed with ramped intensity cyclical bending loads after osteotomy and fixation of one scaphoid with a Herbert screw and fixation of the other with an AO 3.5-millimeter cannulated screw, a Herbert-Whipple screw, an Acutrak cannulated screw, or a Universal Compression screw. The AO screw, Acutrak screw, and Herbert-Whipple screw demonstrated superior resistance to cyclical bending loads compared with the Herbert screw. The Universal Compression screw did not provide better fixation than the Herbert screw because of fractures that occurred at the time of insertion. The AO screw and the Herbert screw were then tested in a separate setup in which a segment of volar cortex had been removed in addition to the simple osteotomy. The loss of volar cortex greatly diminished the quality of the fixation provided by both of the screws during application of ramped intensity cyclical bending loads. A fixation device in the scaphoid must be able to withstand the stresses that are placed on the scaphoid as a result of its position spanning the proximal and distal carpal rows. Also, because of the prolonged time required for healing of fractures or non-unions of the scaphoid, the device must be able to withstand many such cycles of stress. The present study demonstrates that commonly used screws for fixation of the scaphoid vary significantly (p < 0.005) in their ability to resist cyclical bending loads.

  19. Rapid prototyping of scaphoid and lunate bones.

    PubMed

    Gittard, Shaun D; Narayan, Roger J; Lusk, Jason; Morel, Pierre; Stockmans, Filip; Ramsey, Michael; Laverde, Claire; Phillips, Jack; Monteiro-Riviere, Nancy A; Ovsianikov, Aleksandr; Chichkov, Boris N

    2009-01-01

    In this study, a novel rapid prototyping technology was used to fabricate scaphoid and lunate bone prostheses, two carpal bones that are prone to avascular necrosis. Carpal prostheses were fabricated with an Envisiontec Perfactory SXGA stereolithography system using Envisiontec eShell 200 photocurable polymer. Fabrication was guided using 3-D models, which were generated using Mimics software (Materialise NV, Leuven, Belgium) from patient computer tomography data. The prostheses were fabricated in a layer-by-layer manner; approximately 50-microm thick layers were observed in the prostheses. Hardness and Young's modulus values of polymerized eShell 200 material were 93.8 +/- 7.25 MPa and 3050 +/- 90 MPa, respectively. The minimum compressive force required for fracture was 1360 N for the scaphoid prosthesis and 1248 N for the lunate prosthesis. Polymerized Envisiontec eShell material exhibited high human neonatal epidermal keratinocyte cell viability rate in an MTT assay. The results of this study indicate that small bone prostheses fabricated by stereolithography using eShell 200 polymer may have suitable geometry, mechanical properties, and cytocompatibility properties for in vivo use.

  20. Titanium template for scaphoid reconstruction.

    PubMed

    Haefeli, M; Schaefer, D J; Schumacher, R; Müller-Gerbl, M; Honigmann, P

    2015-06-01

    Reconstruction of a non-united scaphoid with a humpback deformity involves resection of the non-union followed by bone grafting and fixation of the fragments. Intraoperative control of the reconstruction is difficult owing to the complex three-dimensional shape of the scaphoid and the other carpal bones overlying the scaphoid on lateral radiographs. We developed a titanium template that fits exactly to the surfaces of the proximal and distal scaphoid poles to define their position relative to each other after resection of the non-union. The templates were designed on three-dimensional computed tomography reconstructions and manufactured using selective laser melting technology. Ten conserved human wrists were used to simulate the reconstruction. The achieved precision measured as the deviation of the surface of the reconstructed scaphoid from its virtual counterpart was good in five cases (maximal difference 1.5 mm), moderate in one case (maximal difference 3 mm) and inadequate in four cases (difference more than 3 mm). The main problems were attributed to the template design and can be avoided by improved pre-operative planning, as shown in a clinical case. © The Author(s) 2014.

  1. PSEUDARTHROSIS OF THE TUBERCLE OF THE SCAPHOID BONE IN IMMATURE SKELETON: CASE REPORT

    PubMed Central

    Gomes, Eduardo Amarai; Armanelli, Felipe; Saliba, Gustavo Augusto Matos

    2015-01-01

    The aim of this study was to present a case report on pseudarthrosis of the scaphoid tubercle, a pathological condition that affects the young and active population. This entity often develops as a result of failure to make an early diagnosis and a late start to treatment. This report describes the case of a 15-year-old patient with a history of a neglected fracture of the scaphoid tubercle that occurred one year earlier and evolved to pseudarthrosis of the tubercle, which is an unusual location for this type of complication. The diagnosis was made from the clinical history and radiographic examination. The treatment was undertaken in accordance with the Matti-Russe technique, by means of a volar route, thus avoiding injury to the scaphoid vascularization, with good clinical and radiographic evolution. Pseudarthrosis of the scaphoid tubercle is a rare condition resulting from a fracture in an unusual location in the scaphoid bone, and it is important because it affects the young and active population. The correct diagnosis is only rarely made by radiologists or surgeons at the time of the fracture, because of failure to recognize this entity. This mistake delays and causes difficulty in treatments for the complications resulting from this kind of fracture. Therefore, it is essential to include this condition in differential diagnoses in order to avoid mistaken conduct. The treatment chosen was shown to be an effective option in this specific case. PMID:27047860

  2. Sensitivity and specificity of CT- and MRI-scanning in evaluation of occult fracture of the proximal femur.

    PubMed

    Haubro, M; Stougaard, C; Torfing, T; Overgaard, S

    2015-08-01

    To estimate sensitivity and specificity of CT and MRI examinations in patients with fractures of the proximal femur. To determine the interobserver agreement of the modalities among a senior consulting radiologist, a resident in radiology and a resident in orthopaedics surgery. 67 patients (27 males, 40 females, mean age 80.5) seen in the emergency room with hip pain after fall, inability to stand and a primary X-ray without fracture were evaluated with both CT and MRI. The images were analysed by a senior consulting musculoskeletal radiologist, a resident in radiology and a resident in orthopaedic surgery. Sensitivity and specificity were estimated with MRI as the golden standard. Kappa value was used to assess level of agreement in both MRI and CT finding. 15 fractures of the proximal femur were found (7 intertrochanteric-, 3 femoral neck and 5 fractures of the greater trochanter). Two fractures were not identified by CT and four changed fracture location. Among those, three patients underwent surgery. Sensitivity of CT was 0.87; 95% CI [0.60; 0.98]. Kappa for interobserver agreement for CT were 0.46; 95% CI [0.23; 0.76] and 0.67; 95% CI [0.42; 0.90]. For MRI 0.67; 95% CI [0.43; 0.91] and 0.69; 95% CI [0.45; 0.92]. MRI was observed to have a higher diagnostic accuracy than CT in detecting occult fractures of the hip. Interobserver analysis showed high kappa values corresponding substantial agreement in both CT and MRI. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Occult fracture of the lesser tuberosity in a 9-year-old female swimmer

    PubMed Central

    Aagaard, KE; Lunsjö, K

    2017-01-01

    The adolescent avulsion of the lesser tuberosity of the humerus has historically been considered as very rare. The youngest patient reported in the literature is 11 years old. We report a case of a 9-year-old girl who suffered a subscapularis tendon tear with an occult avulsion of the lesser tuberosity. Late repair restored function. Despite that late repair in this present case resulted in excellent outcome, we strongly recommend the additional axillary lateral view of the plain radiographs, as well as proper physical examination to facilitate early diagnosis. PMID:28122897

  4. Management of scaphoid nonunion with iliac crest bone graft and K-wire fixation.

    PubMed

    Meisel, Erin; Seal, Alex; Yao, Caroline A; Ghiassi, Alidad; Stevanovic, Milan

    2017-01-01

    Scaphoid nonunion can occur in both non-operative and operatively treated scaphoid fractures. Without treatment, this can lead to a predictable pattern of carpal collapse and degenerative arthritic change and patients can experience both pain and functional loss in the early and late phases of progression. An operative technique with a high success rate for union is important. This paper describes a technique for treatment of scaphoid nonunion with K-wire fixation and iliac crest cancellous bone graft. A retrospective review from 1996 to 2010 was performed on a single senior surgeon's private university-based practice. Patient demographic information and fracture characteristics were obtained to evaluate for influence on success and time to union. There were 32 patients identified for inclusion in this study. Union was achieved in 100% of the patients, including 44% that had proximal pole fractures. The median time from injury to surgery was 41.86 weeks. The median time from surgery to healing was 17.93 weeks. Time to union was not affected by patient age, fracture location, smoking, alcohol use, or time to treatment. K-wire fixation and ICBG for treatment of scaphoid nonunion using our technique have equal or superior union rates compared to other techniques in the literature. This paper highlights the keys to success using this method. Therapeutic Level IV.

  5. Hip and buttock pain due to occult pelvic fractures: a case report

    PubMed Central

    Goldford, Richard J

    1996-01-01

    Pelvic fractures are a relatively uncommon presentation to a chiropractic office. A case is presented of pelvic fractures following a motor vehicle accident that initially went undetected despite a set of lumbar spine and pelvic radiographs. The condition was only discovered when the patient continued to suffer hip and buttock pain that was not improving in a reasonable period of time. Follow-up radiographs revealed well healing, stable pelvic fractures. The classification of pelvic fractures as well as the importance of a high index of suspicion in dealing with patients who have been involved in motor vehicle accidents is discussed. The importance of obtaining an accurate diagnosis and its relevance to duration of disability is highlighted. ImagesFigure 1Figure 2

  6. Characterization of a Pre-Clinical Mini-Pig Model of Scaphoid Non-Union

    PubMed Central

    Behrends, Dominique Andre; Khendek, Leticia; Gao, Chan; Zayed, Nadia; Henderson, Janet Elizabeth; Martineau, Paul Andre

    2015-01-01

    A fractured scaphoid is a common disabling injury that is frequently complicated by non-union. The treatment of non-union remains challenging because of the scaphoid’s small size and delicate blood supply. Large animal models are the most reliable method to evaluate the efficacy of new treatment modalities before their translation into clinical practice. The goal of this study was to model a human scaphoid fracture complicated by non-union in Yucatan mini-pigs. Imaging and perfusion studies were used to confirm that the anatomy and blood supply of the radiocarpal bone in mini-pigs were similar to the human scaphoid. A 3 mm osteotomy of the radiocarpal bone was generated and treated with immediate fixation or filled with a dense collagen gel followed by delayed fixation. Bone healing was assessed using quantitative micro computed tomography and histology. With immediate fixation, the osteotomy site was filled with new bone across its whole length resulting in complete bridging. The dense collagen gel, previously shown to impede neo-vascularization, followed by delayed fixation resulted in impaired bridging with less bone of lower quality. This model is an appropriate, easily reproducible model for the evaluation of novel approaches for the repair of human scaphoid fractures. PMID:26086923

  7. Non-vascularized bone grafting in scaphoid nonunion: principles and type of fixation.

    PubMed

    Uesato, Ryoko; Toh, Satoshi; Hayashi, Yoshimitsu; Maniwa, Keiichiro; Ishibashi, Yasuyuki

    2017-01-01

    In scaphoid fractures, delayed diagnosis and nonunion are fairly common as a result of several factors, including the difficulty of radiographic diagnosis of non-displaced fractures and underestimation of the injury by the patient. Main factors to consider when deciding treatment are the type of fracture and fracture stability. In the stable nonunion (Type D1 according to the Filan and Herbert classification, or linear type of Ikeda's classification), percutaneous screw fixation without bone graft is recommended. The indications of non-vascularized bone grafting are as follows: (1) arthroscopic cancellous bone graft in type D1 and cystic type of Ikeda's classification. (2) tricortical bone graft from the iliac crest in type D2 or D3 if the possibility of avascular necrosis of the proximal fragment is excluded. In this paper, our non-vascularized bone grafting for scaphoid nonunion would like to be described mainly about principles and type of fixation.

  8. Intramedullary Screw and Kirschner Wire Fixation for Unstable Scaphoid Nonunion.

    PubMed

    Allon, Raviv; Kramer, Aviv; Wollstein, Ronit

    2016-12-01

    Surgical treatment of scaphoid nonunion is not always successful, often requiring stabilization and bone grafting to achieve healing. Even after intramedullary screw fixation, residual instability may still hinder union. The purpose of this study was to describe the addition of Kirschner wires (KWs) through the capitate and the lunate to supplement an intramedullary screw for temporary enhanced stability, possibly improving healing of unstable fractures. A case-control study reviewing 25 cases with addition of KWs and 19 controls was performed. Demographic and fracture information, time to diagnosis, and healing time were documented. We found no differences in population characteristics, fracture characteristics, or outcome measures between patients treated with this method and those treated with a screw alone. We had no complications related to the addition of KWs. Preoperative lunate type and scapholunate gapping was suggestive but not significantly associated with KW insertion. Addition of KWs is safe and may be considered in scaphoid nonunion in the presence of intraoperative suboptimal stability. Intraoperative stability may possibly be inferred by reviewing preoperative radiographs for signs of instability.

  9. Use of percussion as a screening tool in the diagnosis of occult hip fractures.

    PubMed

    Tiru, Mohan; Goh, S H; Low, B Y

    2002-09-01

    Traumatic hip pain is a common clinical problem in the emergency department. There is significant morbidity in discharging a patient with an undiagnosed undisplaced hip fracture. The auscultatory percussion technique is a useful method to risk stratify patients who present with traumatic hip pain and with normal radiographs. We sought to study the sensitivity and specificity of the auscultatory percussion technique in a prospective study.

  10. Defining occult injuries of the distal forearm and wrist in children.

    PubMed

    Elvey, Michael; Patel, S; Avisar, Erez; White, W J; Sorene, E

    2016-06-01

    The nonspecific terms "wrist sprain" and "suspected occult bony injury" are frequently documented as diagnoses in occult paediatric wrist injuries. To date, however, no one has accurately defined their true underlying pathology. The primary objective of this study was to identify the true pathoanatomy of occult acute paediatric wrist injuries. Our secondary objective was to compare our findings with existing adult data in order to determine any population differences that might be clinically relevant. We performed a single-centre retrospective case series evaluating MRI findings in acute paediatric wrist injuries presenting to the hand injury unit between 2011 and 2014. All patients underwent standardised radiographs of the wrist and, where clinically indicated, of the scaphoid. Where no bony anomaly was identified, MRI scanning was offered. Cohen's kappa coefficient was used to calculate the agreement between clinical and MRI diagnosis. 57 patients met the final inclusion criteria. Occult fractures and bony contusions comprised the majority of the pathologies, at 36.5 and 35.0 %, respectively. There were no cases of isolated soft-tissue injury. MRI effected management change in 35.1 % of cases. Paediatric wrists demonstrated differences in injury pattern and distribution when compared to an adult population. This study defines for the first time the true pathology of occult paediatric wrist injuries. The current definition of a wrist sprain was not applicable to a single case and therefore appears to be inappropriate for use in the paediatric population. A precise knowledge of the likely pathology facilitates accurate information delivery whilst reducing parental uncertainty and treatment variation.

  11. Open dislocation of the carpal scaphoid: a case report.

    PubMed

    Antuna, S A; Antuna-Zapico, J M

    1997-01-01

    A case of an open volar scaphoid dislocation is presented. The patient was treated surgically, with open reduction of the scaphoid and pinning to the lunate. After 9 years, good clinical and radiographic results were obtained.

  12. Bilateral dorsal trans-scaphoid perilunate fracture–dislocation: A case report

    PubMed Central

    Yildirim, Cengiz; Unuvar, Fatih; Keklikci, Kenan; Demirtas, Mehmet

    2014-01-01

    INTRODUCTION Perilunate dislocations represent one of the most devastating injuries to the carpus. Fortunately, these injuries are relatively rare, constituting approximately 10% of all carpal injuries. One of the problems associated with this injury is the difficulty of its accurate and early recognition. PRESENTATION OF CASE In this study, an uncommon case of bilateral dorsal trans-scaphoid perilunate fracture–dislocation following trauma has been reported. The injury was missed initially and the patient was subsequently operated after two weeks. Anatomic reduction was achieved by closed reduction. After closed reduction, percutaneous pin fixation of the carpus was performed using Kirschner wires. Finally, the scaphoid was stabilized with a headless screw percutaneously. The same procedure was repeated for the other wrist. This was followed by an uneventful post-operative period, with a satisfactory functional outcome at the two-year follow-up, despite non-union of the scaphoid in one side. DISCUSSION The case was examined in detail, and compared to the findings in the literature; observations regarding fracture prognosis were also made. Most authors agree that closed reduction is the initial treatment of choice for trans-scaphoid perilunate fracture–dislocations. In addition, treatment often requires intercarpal fixation within the proximal carpal row. CONCLUSION We believe that closed reduction in these cases should be attempted regarding the potential risks of avascular necrosis and non-union of the affected carpal bones due to open reduction. PMID:24705189

  13. KBO Occultation

    NASA Astrophysics Data System (ADS)

    Rijsdijk, C.

    2016-12-01

    A recommendation to astronomers to observe an occultation by the Kuiper Belt Object KBO 2014MU69. Its first predicted stellar occultation, in early June 2017, of a 15th magnitude star, will be visible from Southern Africa.

  14. In vitro experimental investigation of the forces and torque acting on the scaphoid during light grasp.

    PubMed

    Erhart, Jochen; Unger, Ewald; Schefzig, Philip; Krumboeck, Anna; Hagmann, Michael; Vecsei, Vilmos; Mayr, Winfried

    2016-10-01

    The aim of this study was to measure the magnitude and direction of forces and torque within osteotomized scaphoids within cadaveric wrists during grasping movement of the hand. The mechanical contributions of clinically relevant individual wrist-crossing tendon groups were investigated. Wrists of eight forearms were immobilized in the sagittal, transverse, and coronal plane on a fixation device with unhindered axial gliding. The scaphoid was osteotomized and the fragments stabilized using an interlocking nail. The nail served as a sensor for measurement of inter-fragmentary forces orthogonal and torque around the sensor axis. Thus, torque and cantilever forces were measured which originated between the fragments through co-contraction through the activity of wrist-crossing tendons. Grasping movement of the hand induced a mean maximum torque of 0.038 ± 0.051 Nm and a force of 4.01 ± 1.71 N on the scaphoid. The isolated activation of thumb tendons resulted in a torque of 9.9 E(-3 ) ± 7.7 E(-3 ) Nm and a force of 1.42 ± 0.49 N. Despite immobilization of the wrist, grasping movement of the hand caused substantial forces and torque within the osteotomized scaphoid bone in varying directions and severity among different specimens. These factors may contribute to the development of nonunions and malunions in unstable scaphoid fractures through interfragmentary micromotion. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1734-1742, 2016. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  15. Palmar divergent dislocation of scaphoid and lunate.

    PubMed

    Kang, Ho-Jung; Shim, Dong-Joon; Hahn, Soo-Bong; Kang, Eung-Shick

    2003-12-30

    A 28-year-old man presented with a palmar divergent dislocation of the scaphoid and lunate. He was treated with an open reduction and an internal fixation with two Kirschner's wires after the 25th day of trauma due to a neurological injury. The results were satisfactory after 18 months follow up without any evidence of avascular necrosis and traumatic arthritis of the scaphoid and lunate. The patient had no limitation in motion or intermittent wrist pain. We reported this case with a brief review of relevant literatures.

  16. Early active motion protocol following open reduction internal fixation of the scaphoid: A pilot study.

    PubMed

    Dunn, J-C; Kusnezov, N; Fares, A; Buccino, Z; Esquivel, D; Mitchell, J

    2017-02-01

    Scaphoid fractures are common injuries which traditionally have been treated with long periods of immobilization even after open reduction and internal fixation (ORIF). The purpose of this pilot investigation was two-fold: 1) describe a precise postoperative Early Active Motion (EAM) rehabilitation protocol following ORIF of scaphoid fractures and 2) record the outcomes of the EAM protocol. Eight consecutive patients having undergone ORIF of the scaphoid were enrolled in the EAM and followed for a minimum of 1 year. At 12 weeks, Disabilities of the Arm Shoulder and Hand (DASH) score, Mayo Wrist score, and range of motion values were obtained. At 1 year, a telephone survey was conducted and several data points were obtained including DASH and Mayo Wrist score, number of push-ups, satisfaction with surgery and ability to remain on active duty. All 8 patients were male, on active duty, with an average age of 26 years. Two patients used tobacco products and none had major health problems. All patients completed the EAM protocol and obtained CT; all CT exams demonstrated healing at 8 weeks. At 12 weeks postoperatively, the average DASH score was 8.8±16 (range: 0-47.5), Mayo wrist score was 88±10 (range: 75-100) and range of motion nearly symmetrical. At a mean final follow-up of 15.4 months postoperatively, the average DASH score was 1.1±1.7 (Range: 0-4.5), Mayo wrist score was 97.5±4 (range 90-100), average number of push-ups was 57 (40-70) at the prior Army Physical Fitness Test. All patients were satisfied with surgery and all remained on active duty at 1 year. There were no reported complications. The EAM protocol following scaphoid fracture ORIF is safe and effective. The EAM can reliably return patients back to high demand activity earlier than a traditional protocol.

  17. [Pseudoarthrosis of the scaphoid bone associated with carpal collapse: factors in choice of surgical approach].

    PubMed

    Miric, D; Senohradski, K; Vucetic, C; Djordjevic, Z

    2001-01-01

    The most common fracture involving the wrist is a fracture of the scaphoid bone [1], and only 5% to 10% of these fractures proceed to nonunion. Although not symptomatic initially, most (if not all) nonunions later produce a painful wrist with impaired function, clinically significant loss of motion, increased weakness and degenerative arthritis. Nonunion of the scaphoid bone should be treated by open reduction and internal fixation. Many surgical procedures have been advocated to achieve union. Most widely used technique for the treatment of scaphoid nonunion was described by Russe [2], but this method may overcome the flexion deformity of the scaphoid and carpal deformities. The ununited scaphoid usually undergoes resorption of the fractures surfaces, principally over the anterolateral aspect of the fracture, so that the scaphoid becomes misshapen. The restoration of the exact length and form is enabled by insertion of a tight-fitting trapezoidal corticocancellous graft, a technique described by Fernandez [11]. We analysed the results of treatment of scaphoid nonunion utilized by two bone-grafting techniques and pointed out the need of choice of the best operative method. From 1977 to 1993, at the Institute of Orthopaedic Surgery and Traumatology in Belgrade, 40 patients were surgically treated for symptomatic nonunion of the scaphoid bone. The mean duration of follow-up was 10.2 years (range, from 6 to 22 years). Eighteen (45%) patients were operated by Fernandez technique and 22 (55%) patients were operated using Russe's technique. Volar approach and Kirschner's wire fixation were performed in both operative methods. We used two rating scales proposed by Cooney [13] to evaluate the results. Objective scale (Table 1a) included the radiographic appearance of the wrist, the range of motion and grip strength. Subjective scale (Table 1b) comprised function, pain perception of a decrease in performance because of limited motion or strength, and satisfaction. These

  18. Herbert screw fixation for scaphoid nonunions. An analysis of factors influencing outcome.

    PubMed

    Inoue, G; Shionoya, K; Kuwahata, Y

    1997-10-01

    A retrospective review of 160 cases of scaphoid nonunion treated by internal fixation using a Herbert screw with bone grafting was conducted at an average followup of 24 months. Definite radiographic union was achieved in 90% of cases. Based on Cooney's clinical scoring system, 80 cases had an excellent result, 37 had a good result, 33 had a fair result, and 10 had a poor result. Failure of union was related to the existence of avascular changes of the proximal fragment, instability of the fracture fragment, the prolonged delay in surgery, and the location of the fracture site. In the united scaphoids, the lengthy period of postoperative immobilization, the existence of osteoarthritis, and the prolonged delay in surgery were significant factors in the patient's functional outcome. Overall, the results do not support the view that a residual flexion deformity of the scaphoid is less likely to yield a satisfactory outcome, although it seems worthwhile to correct excessive angulation at the time of repair to promote an anatomic union, thereby preventing early arthritis. A bone graft with internal fixation using a Herbert screw and a shorter period of immobilization may give a satisfactory functional result when the nonunion is treated before the onset of arthritic changes in the wrist.

  19. Palmar dislocation of scaphoid and lunate.

    PubMed

    Idrissi, Khalid Koulali; Galiua, Farid

    2011-09-28

    A palmar dislocation of scaphoid and lunate is uncommon. We have found only 19 reported cases in the literature. We reported a simultaneous, divergent dislocation. The closed reduction followed by percutaneous pinning has given a good result without avascular necrosis of any carpal bone.

  20. The use of MRI to detect occult fractures of the proximal femur: a study of 102 consecutive cases over a ten-year period.

    PubMed

    Sankey, R A; Turner, J; Lee, J; Healy, J; Gibbons, C E R

    2009-08-01

    An MR scan was performed on all patients who presented to our hospital with a clinical diagnosis of a fracture of the proximal femur, but who had no abnormality on plain radiographs. This was a prospective study of 102 consecutive patients over a ten-year period. There were 98 patients who fulfilled our inclusion criteria, of whom 75 were scanned within 48 hours of admission, with an overall mean time between admission and scanning of 2.4 days (0 to 10). A total of 81 patients (83%) had abnormalities detected on MRI; 23 (23%) required operative management. The use of MRI led to the early diagnosis and treatment of occult hip pathology. We recommend that incomplete intertrochanteric fractures are managed non-operatively with protected weight-bearing. The study illustrates the high incidence of fractures which are not apparent on plain radiographs, and shows that MRI is useful when diagnosing other pathology such as malignancy, which may not be apparent on plain films.

  1. Scaphoid Plate Fixation and Volar Carpal Artery Vascularized Bone Graft for Recalcitrant Scaphoid Nonunions.

    PubMed

    Dodds, Seth D; Halim, Andrea

    2016-07-01

    We sought to evaluate the clinical and radiographic outcomes after treatment of symptomatic, recalcitrant scaphoid nonunions using a novel combination of volar scaphoid buttress plating with a pedicled vascularized bone graft. We retrospectively followed 9 patients with recalcitrant scaphoid waist nonunions, characterized by failed prior surgery, long duration of nonunion, avascular necrosis of the proximal pole, or considerable bone loss at the nonunion site. We treated these persistent nonunions through a single volar incision with a pedicled vascularized bone graft, based on the volar carpal artery, and a 1.5-mm precontoured, scaphoid-specific, volar buttress plate. Postoperatively, we assessed objective and subjective outcomes as well as radiographs and computed tomography scans. The median duration of nonunion was 15 months, ranging from 6 to 96 months. Postoperative follow-up ranged from 11 to 19 months. Computed tomography scans demonstrated union in 8 of 9 cases. Complications included 1 minor hematoma that spontaneously resolved. One scaphoid failed to unite, requiring revision surgery. Three patients experienced problems with the plate. One plate was removed from a patient who noted persistent clicking, and 2 plates have caused symptomatic clicking, likely requiring future removal. Eight of nine patients reported satisfaction with the procedure, with QuickDash scores averaging 8.2. We present a series of recalcitrant scaphoid nonunions treated with a novel technique of volar buttress plating and vascularized bone graft. In this series, we found a high rate of union, with consistent radiographic improvement and symptomatic relief. This procedure can be performed using a single incision and with minimal donor site morbidity. Volar plating of a scaphoid nonunion comes with the risk of articular prominence, but offers a new alternative to headless screw fixation. Our early results from this series are promising and support this protocol as a viable

  2. The use of the free vascularised bone graft for nonunion of the scaphoid: a systematic review

    PubMed Central

    2014-01-01

    Background Fractures of the scaphoid are well known to be problematic especially when complicated by avascular necrosis, nonunion and carpal collapse. Fixation techniques have involved nonvascularised bone grafting; however, in the presence of avascular necrosis, generally poor union rates (47%) occur as identified by a meta-analysis performed by Merrell et al. The introduction of pedicled vascularised bone grafts showed further improvement; however, in the presence of carpal collapse, union rates as low as 50% have been reported by Chang et al. amongst others using the 1,2-intercompartmental supraretinacular artery pedicled graft. The difficulty lies in having a short pedicle with limited manoeuvrability to correct a humpback deformity and insert into the scaphoid cavity. Prior trauma to the soft tissues or distal radius may prohibit the use of pedicled grafts. The aim of this systematic review is to examine the published evidence for the use of free vascularised bone grafts in cases of scaphoid nonunion. Methods A systematic review was performed with the following defined search strategy on MEDLINE and Google Scholar: ((scaphoid nonunion) OR scaphoid pseudarthrosis) AND bone graft. Articles were reviewed and data compiled into tables for analysis. Statistical analysis was performed with determination of descriptive statistics, and differences between the groups were calculated using categorical variables and chi-square test. A p value of 0.05 or less was considered to be statistically significant. Results Two hundred and sixty-three articles were identified with a total of 12 articles meeting the inclusion criteria. Two hundred and forty-five cases of scaphoid nonunion were identified through the articles included in this systematic review. Fifty-six patients underwent free vascularised bone grafts from the medial femoral condyle with a 100% union rate and correction of humpback deformity, and 188 patients underwent free vascularised bone grafting from the iliac

  3. Validity of computed tomography in predicting scaphoid screw prominence: a cadaveric study.

    PubMed

    Griffis, Clare E; Olsen, Cara; Nesti, Leon; Gould, C Frank; Frew, Michael; McKay, Patricia

    2017-04-01

    Studies of hardware protrusion into joint spaces following fracture fixation have been performed to address whether or not there is discrepancy between the actual and radiographic appearance of screw prominence. The purpose of our study was to prove that, with respect to the scaphoid, prominence as visualized on CT scan is real and not a result of metal artifact. Forty-two cadaveric wrists were separated into four allotted groups with 21 control specimens and 21 study specimens. All specimens were radiographically screened to exclude those with inherent carpal abnormalities. Acutrak® headless compression screws were placed into all specimens using an open dorsal approach. Cartilage was removed from screw insertion site at the convex surface of the scaphoid proximal pole. Control specimens had 0 mm screw head prominence. The studied specimens had 1, 2, and 3 mm head prominence measured with a digital caliper. Computed tomography, with direct sagittal acquisition and metal suppression technique, was then performed on all specimens following screw placement. Two staff radiologists blinded to the study groups interpreted the images. Results revealed that only one of 21 control specimens was interpreted as prominent. Comparatively, in the studied groups, 90% were accurately interpreted as prominent. CT provides an accurate assessment of scaphoid screw head prominence. When a screw appears prominent on CT scan, it is likely to be truly prominent without contribution from metallic artifact.

  4. Occult intracranial injury in infants.

    PubMed

    Greenes, D S; Schutzman, S A

    1998-12-01

    The objectives of this study were as follows: (1) to determine whether clinical symptoms and signs of brain injury are sensitive indicators of intracranial injury (ICI) in infants admitted with head trauma, (2) to describe the clinical characteristics of infants who have ICI in the absence of symptoms and signs of brain injury, and (3) to determine the clinical significance of those ICIs diagnosed in asymptomatic infants. We conducted a retrospective analysis of all infants younger than 2 years of age admitted to a tertiary care pediatric hospital with acute ICI during a 6(1/2)-year period. Infants were considered symptomatic if they had loss of consciousness, history of behavior change, seizures, vomiting, bulging fontanel, retinal hemorrhages, abnormal neurologic examination, depressed mental status, or irritability. All others were considered to have occult ICI. Of 101 infants studied, 19 (19%; 95% confidence interval [CI] 12%, 28%) had occult ICI. Fourteen of 52 (27%) infants younger than 6 months of age had occult ICI, compared with 5 of 34 (15%) infants 6 months to 1 year, and none of 15 (0%) infants older than 1 year. Eighteen (95%) infants with occult ICI had scalp contusion or hematoma, and 18 (95%) had skull fracture. Nine (47%) infants with occult ICI received therapy for the ICI. No infants with occult ICI (0%) (95% CI 0, 14%) required surgery or medical management for increased intracranial pressure. Only 1 subject (5%) with occult ICI had any late symptoms or complications: a brief, self-limited convulsion. We found that 19 of 101 ICIs in infants admitted with head trauma were clinically occult. All 19 occult ICIs occurred in infants younger than 12 months of age, and 18 of 19 had skull fractures. None experienced serious neurologic deterioration or required surgical intervention. Physicians cannot depend on the absence of clinical signs of brain injury to exclude ICI in infants younger than 1 year of age.

  5. Treatment of Nonunion of Scaphoid Waist with Ni-Ti Shape-Memory Alloy Connector and Iliac Bone Graft

    NASA Astrophysics Data System (ADS)

    Cao, Lie-Hu; Xu, Shuo-Gui; Wu, Ya-Le; Zhang, Chun-Cai

    2011-07-01

    After fracture, the unique anatomy and blood supply of the scaphoid itself predisposes to nonunion. Scaphoid nonunion presents a formidable challenge to surgeons because of the difficulties for fixation, and the high failure rate after treatment. The Ni-Ti shape-memory alloy can provide compressive stress at the nonunion site, which is the key point for bone healing. Hence, we designed a shape-memory bone connector named arched shape-memory connector (ASC). We conducted a retrospective study looking at the union rate and complications and correlating the outcome of treatment with this device. The study reviewed a cohort of six consecutive patients presenting with scaphoid waist nonunion, who were treated with ASC and iliac cancellous bone grafting at our center from August 2002 to December 2007. The patients with nonunion achieved a 100% union rate. All the patients who achieved union had good pain relief and improved function. Our study demonstrates that scaphoid waist nonunions can be successfully treated by ASC and iliac bone grafting.

  6. Detection of occult, undisplaced hip fractures with a dual-energy CT algorithm targeted to detection of bone marrow edema.

    PubMed

    Reddy, T; McLaughlin, P D; Mallinson, P I; Reagan, A C; Munk, P L; Nicolaou, S; Ouellette, H A

    2015-02-01

    The purpose of this study is to describe our initial clinical experience with dual-energy computed tomography (DECT) virtual non-calcium (VNC) images for the detection of bone marrow (BM) edema in patients with suspected hip fracture following trauma. Twenty-five patients presented to the emergency department at a level 1 trauma center between January 1, 2011 and January 1, 2013 with clinical suspicion of hip fracture and normal radiographs were included. All CT scans were performed on a dual-source, dual-energy CT system. VNC images were generated using prototype software and were compared to regular bone reconstructions by two musculoskeletal radiologists in consensus. Radiological and/or clinical diagnosis of fracture at 30-day follow-up was used as the reference standard. Twenty-one patients were found to have DECT-VNC signs of bone marrow edema. Eighteen of these 21 patients were true positive and three were false positive. A concordant fracture was clearly seen on bone reconstruction images in 15 of the 18 true positive cases. In three cases, DECT-VNC was positive for bone marrow edema where bone reconstruction CT images were negative. Four patients demonstrated no DECT-VNC signs of bone marrow edema: two cases were true negative, two cases were false negative. When compared with the gold standard of hip fracture determined at retrospective follow-up, the sensitivity of DECT-VNC images of the hip was 90 %, specificity was 40 %, positive predictive value was 86 %, and negative predictive value was 50 %. Our initial experience would suggest that DECT-VNC is highly sensitive but poorly specific in the diagnosis of hip fractures in patients with normal radiographs. The value of DECT-VNC primarily lies in its ability to help detect fractures which may be subtle or undetectable on bone reconstruction CT images.

  7. Transstyloid, transscaphoid, transcapitate fracture: a variant of scaphocapitate fractures

    PubMed Central

    Burke, Neil G; Cosgrave, Ciaran H; O'Neill, Barry James; Kelly, Eamonn P

    2014-01-01

    Transstyloid, transscaphoid, transcapitate fractures are uncommon. We report the case of a 28-year-old man who sustained this fracture following direct trauma. The patient was successfully treated by open reduction internal fixation of the scaphoid and proximal capitate fragment, with a good clinical outcome at 1-year follow-up. This pattern is a new variant of scaphocapitate fracture as involves a fracture of the radial styloid as well. PMID:24686808

  8. Nontraumatic osteonecrosis of the distal pole of the scaphoid

    PubMed Central

    Garg, Bhavuk; Gupta, Himanshu; Kotwal, Prakash P

    2011-01-01

    Post traumatic osteonecrosis of distal pole of scaphoid is very rare. We present a case of 34 years old male, drill operator by occupation with nontraumatic osteonecrosis of distal pole of the scaphoid. The patient was managed conservatively and was kept under regular follow-up every three months. The patient was also asked to change his profession. Two years later, the patient had no pain and had mild restriction of wrist movements (less than 15 degrees in either direction). The radiographs revealed normal density of the scaphoid suggesting revascularization. PMID:21430877

  9. Grazing Occultations.

    ERIC Educational Resources Information Center

    Cunningham, Doug; Hlynialuk, John

    1983-01-01

    A "grazing occultation" occurs when a star or other astronomical body is covered up by the extreme northern or southern limb of the moon in its easterly motion about the earth. Graze phenomena, organizing a graze expedition, and the scientific/educational value of observing grazes are among the topics discussed. (JN)

  10. Palmar-divergent dislocation of the scaphoid and the lunate.

    PubMed

    Komura, Shingo; Yokoi, Tatsuo; Suzuki, Yasushi

    2011-03-01

    We describe a patient with palmar-divergent dislocation of the scaphoid and lunate. After successful closed reduction, the scapholunate and lunotriquetral ligaments were sutured through the dorsal approach, and the anterior capsule was sutured through the palmar approach. The scapholunate and lunotriquetral joints were fixed with Kirschner wires for 7 weeks. At the 1-year follow-up, magnetic resonance imaging showed no evidence of avascular necrosis of the scaphoid or lunate, and radiographs showed no evidence of the dorsal and volar intercalated segment instability patterns associated with carpal instability. However, flexion of the scaphoid and a break in Gilula's line remained. To our knowledge, this is the first report showing treatment of palmar-divergent dislocation of the scaphoid and lunate by suturing the carpal interosseous ligaments.

  11. Interfragmentary compression forces of scaphoid screws in a sawbone cylinder model.

    PubMed

    Hausmann, J T; Mayr, W; Unger, E; Benesch, T; Vécsei, V; Gäbler, C

    2007-07-01

    Various screws have been developed to stabilise fractures of the scaphoid. Commonly used are the Herbert, the HBS, the 3-mm AO and the Acutrak screws. Not long ago a new screw, the Twin Fix, was introduced. This is cannulated and similar in shape and appearance to the classical Herbert screw. In our test series we compared the maximum achievable compression forces of the Twin Fix screw with that of three other screws (AO, HBS and Acutrak screws). To avoid the variations of density, stiffness and rigidity in natural bone, a polyurethane sawbone-based test setup was used. The test series included 10 screws of each type. The compression force was measured using a special strain gauge. The mean compression force was significantly higher for the Twin Fix screw (8+/-1N) and the Acutrak screw (7.6+/-0.4/0.6N) in relation to the AO screw (6.8+/-1.0/1.4N) and HBS screw (2+/-1N). We found the Twin Fix and Acutrak screws to be promising in the treatment of scaphoid fractures.

  12. Osteoid osteoma of the scaphoid: magnetic resonance imaging vessel sign.

    PubMed

    Kussman, Steven R; Thompson, Michael; Chang, Eric Y

    2015-01-01

    Osteoid osteomas can be a challenging diagnosis, especially in smaller bones and, particularly, in the carpus. Clinical and imaging diagnosis may both be delayed due to other, more common, post-traumatic or inflammatory pathology in the same area. We present a case of a pathologically proven scaphoid osteoid osteoma with a feeding vessel sign on magnetic resonance imaging, previously described in long bones with computed tomography, as a helpful sign for accurate diagnosis in the scaphoid.

  13. Management of scaphoid nonunion with avascular necrosis using 1,2 intercompartmental supraretinacular arterial bone graft

    PubMed Central

    Dehghani, Mohamad; Soltanmohamadi, Mohamad; Tahririan, Mohammad Ali; Moezi, Mehdi; Daneshpajouhnejad, Parnaz; Zarezadeh, Abolghasem

    2014-01-01

    Background: 1,2 ICSRA, introduced by Aidembery et al., is a well-established technique, with up to 100% union rate among different studies. The purpose of our study was to evaluate the outcome of scaphoid nonunion undergoing 1,2 ICSRA bone graft in Iran. Materials and Methods: All participants who presented sequentially over a period of 24 months between 2010 and 2013 with nonunion scaphoid fracture with AVN in proximal pole were included in the study. Anteroposterior and lateral view plain radiographs of carpal bones were obtained for diagnosis of nonunion, and a diagnosis of avascular necrosis was made by MRI of the scaphoid. Subjects underwent 1,2 ICSRA bone graft surgery. Patients were assessed based on radiographs and the Mayo Wrist Score (MWS) questionnaire on before and after surgery. Data were analyzed using SPSS ver. 18 by paired t test. Results: Overall, 16 patients (100% male) were included in the study. Mean age of subjects was 27.50 ± 5.86 (18 to 38). Mean Mayo score was 36.63 ± 8.92 and 83.75 ± 9.22 before and 6 month after surgery, respectively, and the difference was statistically significant (P < 0.001). after 8 weeks, 10 (62.5%) had union, and after 12 weeks, all subjects had union. Nine (56.25%) of our patients had excellent functional outcome, 5 (31.25%) had good and 2 (12.5%) had satisfactory functional outcome. Conclusion: 1,2 ICSRA is a proper pedicle of vascularized bone graft due to the ease of visibility and dissection. The functional results and union rates were satisfactory in our study. PMID:25250299

  14. 21 CFR 888.3760 - Wrist joint carpal scaphoid polymer prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Wrist joint carpal scaphoid polymer prosthesis. 888.3760 Section 888.3760 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... scaphoid polymer prosthesis. (a) Identification. A wrist joint carpal scaphoid polymer prosthesis is a...

  15. 21 CFR 888.3760 - Wrist joint carpal scaphoid polymer prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Wrist joint carpal scaphoid polymer prosthesis. 888.3760 Section 888.3760 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... scaphoid polymer prosthesis. (a) Identification. A wrist joint carpal scaphoid polymer prosthesis is a...

  16. 21 CFR 888.3760 - Wrist joint carpal scaphoid polymer prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Wrist joint carpal scaphoid polymer prosthesis. 888.3760 Section 888.3760 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... scaphoid polymer prosthesis. (a) Identification. A wrist joint carpal scaphoid polymer prosthesis is a one...

  17. 21 CFR 888.3760 - Wrist joint carpal scaphoid polymer prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Wrist joint carpal scaphoid polymer prosthesis. 888.3760 Section 888.3760 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... scaphoid polymer prosthesis. (a) Identification. A wrist joint carpal scaphoid polymer prosthesis is a one...

  18. 21 CFR 888.3760 - Wrist joint carpal scaphoid polymer prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Wrist joint carpal scaphoid polymer prosthesis. 888.3760 Section 888.3760 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... scaphoid polymer prosthesis. (a) Identification. A wrist joint carpal scaphoid polymer prosthesis is a one...

  19. Proximal Scaphoid Arthroplasty Using the Medial Femoral Trochlea Flap

    PubMed Central

    Higgins, James P.; Burger, Heinze K.

    2013-01-01

    Background The medial trochlea of the femur (medial femoral trochlea, MFT) provides a source of convex osteocartilaginous vascularized bone that has been demonstrated to have a similar contour to the proximal scaphoid. This provides a potential solution for difficult recalcitrant proximal pole scaphoid nonunions. Materials and Methods Sixteen consecutive patients who underwent MFT proximal scaphoid arthroplasty were reviewed. Follow-up data were recorded at a minimum of 6 months, with an average of 14 months. The results of this cohort were previously reported in detail but are summarized herein. Description of Technique The ability to reconstruct both bone and cartilage of the nonunion enables the surgeon to resect the nonunited proximal pole to prepare for scaphoid reconstruction. A segment of osteocartilaginous MFT is harvested in dimensions required by the scaphoid defect. The MFT segment is harvested on the transverse branch of the descending geniculate vessels. Fixation may be achieved with ease due to the size of the reconstructed segment. Results Computed tomography imaging demonstrated 15 of 16 reconstructed scaphoids achieving osseous union. Follow-up range of motion (ROM) of the wrist averaged 46.0° extension (range 28-80°) and 43.8° flexion (range 10-80°), which was similar to preoperative (average 45.7° extension and 43.0° flexion). Scapholunate angles remained unaffected (51.6° preoperatively and 48.6° postoperatively), indicating preservation of carpal relationships. Conclusions Vascularized MFT flaps provide a useful tool in the treatment of difficult proximal pole scaphoid nonunions. Early follow-up demonstrates high rate of achieving union with acceptable ROM and good pain relief. PMID:24436821

  20. Flexor Tendon Ruptures After Distal Scaphoid Excision for Scaphotrapeziotrapezoid Osteoarthritis.

    PubMed

    Deren, Matthew E; Mitchell, Charles H; Weiss, Arnold-Peter C

    2017-09-01

    Distal scaphoid excision is one treatment option for osteoarthritis of the scaphotrapeziotrapezoid (STT) joint following failure of conservative measures. Potential complications of this procedure include injury to the carpal ligaments, cartilage, and radial artery. A single case was identified by the senior author, and the medical record was reviewed for surgical notes, progress notes, and radiographs. A 68-year-old male sustained ruptures of the flexor digitorum superficialis (FDS) and flexor digitorum profundus to the index finger 3 years following a distal scaphoid excision for symptomatic STT osteoarthritis. He required a flexor tendon reconstruction using the remaining FDS tendon for graft incorporated with a Pulvertaft weave. His midcarpal pain continued after recovery of his index finger function, eventually requiring a 4-corner fusion of the wrist. Flexor tendon rupture is a previously unreported complication of distal scaphoid excision for STT arthritis.

  1. In Vivo Kinematics of the Scaphoid, Lunate, Capitate, and Third Metacarpal in Extreme Wrist Flexion and Extension

    PubMed Central

    Rainbow, Michael J; Kamal, Robin N; Leventhal, Evan; Akelman, Edward; Moore, Douglas C; Wolfe, Scott W; Crisco, Joseph J

    2013-01-01

    the extremes of wrist motion, which occur during activities and injuries, and give insight into the possible etiologies of the scaphoid fractures, interosseous ligament injuries, and carpometacarpal bossing. PMID:23266007

  2. [Fracture of the lunate--a rare injury].

    PubMed

    Höcker, K; Renner, J

    1995-09-01

    Fractures of the normal lunate--isolated or associated with fractures of the scaphoid or radius--are very rare. In the Traumatological Hospital Meidling/Vienna, 12 patients with acute fractures of the lunate bone were treated between 1983 and 1993. Dependent on the fracture-line and the intraosseous vascularity, partial or total avascular necrosis of the bone occurs in rare cases. In dislocated pole fractures, surgical intervention is indicated.

  3. The Occult Today: Why?

    ERIC Educational Resources Information Center

    Kessler, Gary E.

    1975-01-01

    Author offered some reflections on the "why" of the contemporary interest in the occult. He attempted to convince the reader that, if he or she has been surprised by the recent rise of occultism, sober reflection will dispell some fears and, perhaps, even convince him or her that occultism is not merely superstition. (Author/RK)

  4. Using a tightRope® to treat a complex fracture of the trapezium

    PubMed Central

    Mohan, A; Sarkhel, T

    2014-01-01

    We present the case of a 23-year-old man with a combined scaphoid fracture and comminuted trapezium fracture, treated surgically with percutaneous fixation of the scaphoid fracture and concomitant Arthrex Mini TightRope® stabilisation of base of thumb metacarpal to base of index finger metacarpal. The patient made a good functional recovery, returning to usual activities within six weeks. We suggest that this technique could be used to treat complex trapezium fractures that cannot be reconstructed with surgery. PMID:25245724

  5. Extracorporeal shockwaves versus surgery in the treatment of pseudoarthrosis of the carpal scaphoid.

    PubMed

    Notarnicola, A; Moretti, L; Tafuri, S; Gigliotti, S; Russo, S; Musci, L; Moretti, B

    2010-08-01

    The peculiar anatomical characteristics and precarious vascularization of the carpal scaphoid are responsible for a difficult healing of fractures and a fairly frequent subsequent evolution to pseudoarthrosis. Recently, extracorporeal shockwaves therapy (ESWT) has yielded encouraging results in the treatment of pseudoarthrosis of various bone segments. We report a retrospective study comparing the results of application of three sessions of shockwaves therapy (SW) with energy flux density (EFD) impulses of 0.09 (SD = 0.02) mJ/mm(2) ESWT emitted by an electromagnetic generator in 58 patients (group I) affected by pseudoarthrosis of the carpal scaphoid, with the results of surgical treatment consisting of stabilization and bone graft according to the Matti-Russe technique, performed in 60 subjects (controls, group II). There were no statistically significant differences in the mean duration of the pseudoarthrosis (p = 0.46), sex distribution (p = 0.41) and mean age at recruitment (p = 0.95) between the two patient groups. Posttreatment clinical-functional assessment, based on the Mayo Wrist Score, showed a significantly improved score, rising from 28-74.6 in group I already after 2 mo (p < 0.001), with 86.3% of the results judged as satisfactory or excellent; in group II the mean score rose from 27.5-74.2 after 2 mo, with 83.4% of the results judged as satisfactory or excellent (p < 0.001). At the same two-months follow-up (FU), radiographic consolidation was shown in 75.9% of patients in group I and 76.7% in group II. These improvements persisted at the subsequent controls at six and 12 mo in both groups. The Mayo Wrist Score and X-rays did not show statistically significant differences at the various FU visits in the two groups (p > 0.05). On the basis of our data, we can conclude that the results of ESWT are comparable with those of surgical stabilization and bone graft in the treatment of scaphoid pseudoarthrosis. In view of their minimal invasiveness, shockwaves

  6. Pediatric Scaphoid Proximal Pole Nonunion With Avascular Necrosis.

    PubMed

    Jernigan, Edward W; Smetana, Brandon S; Patterson, J Megan M

    2016-12-24

    A 13-year-old, right hand-dominant, otherwise healthy boy presented with left wrist pain 19 months after a nonmotorized scooter injury. Radiographs and magnetic resonance imaging at presentation demonstrated proximal pole scaphoid nonunion with avascular necrosis of the proximal fragment. Operative and nonsurgical treatment options were discussed and the family elected for an attempt at nonsurgical management. The patient was placed in a short-arm thumb spica cast, with a window for a bone stimulator, for 14 weeks. At the conclusion of the treatment, the pain had resolved and x-ray and computed tomography scan demonstrated bony union. The authors recommend considering an initial trial of nonsurgical management for treatment of all pediatric scaphoid nonunions.

  7. Coexisting avascular necrosis of the scaphoid and lunate.

    PubMed

    Park, Il-Jung; Lee, Sang-Uk; Kim, Hyoung-Min

    2010-11-01

    Reports of coexisting avascular necrosis of more than one carpal bone are rare. We report coexisting avascular necrosis of the scaphoid and lunate in a 56-year-old woman with no history of using steroids or injury. We treated her with a radioscapholunate fusion with two angled 2.4 mm distal radius plates to stabilise the locking plate. At her 12-month follow up there was no evidence of non-union.

  8. [Isolated dislocation of the carpal scaphoid. A case report with review of the literature].

    PubMed

    Cherif, M R; Ben Ghozlen, R; Chehimi, A; Annabi, H; Trabelsi, M; Mbarek, M; Ben Hassine, H

    2002-10-01

    Isolated dislocation of the carpal scaphoid is an extremely rare injury, which is usually accompanied by significant ligamento-capsular lesions. A review of the literature found only 21 reported cases. The aim of this report is to present a single case of isolated radio-palmar dislocation of the scaphoid treated conservatively, which provided a good functional result at 10 years follow up.

  9. Deep shadow occulter

    NASA Technical Reports Server (NTRS)

    Cash, Webster (Inventor)

    2010-01-01

    Methods and apparatus are disclosed for occulting light. The occulter shape suppresses diffraction at any given size or angle and is practical to build because it can be made binary to avoid scatter. Binary structures may be fully opaque or fully transmitting at specific points. The diffraction suppression is spectrally broad so that it may be used with incoherent white light. An occulter may also include substantially opaque inner portion and an at least partially transparent outer portion. Such occulters may be used on the ground to create a deep shadow in a short distance, or may be used in space to suppress starlight and reveal exoplanets.

  10. Rotational Stability of Scaphoid Osteosyntheses: An In Vitro Comparison of Small Fragment Cannulated Screws to Novel Bone Screw Sets

    PubMed Central

    Erhart, Jochen; Unger, Ewald; Schefzig, Philip; Varga, Peter; Trulson, Inga; Gormasz, Anna; Trulson, Alexander; Reschl, Martin; Hagmann, Michael; Vecsei, Vilmos; Mayr, Winfried

    2016-01-01

    Background The current standard of care for operative repair of scaphoid fractures involves reduction and internal fixation with a single headless compression screw. However, a compression screw in isolation does not necessarily control rotational stability at a fracture or nonunion site. The single screw provides rotational control through friction and bone interdigitation from compression at the fracture site. We hypothesize that osteosyntheses with novel bone screw sets (BSS) equipped with anti-rotational elements provide improved rotational stability. Methods Stability of osteosynthesis under increasing cyclic torsional loading was investigated on osteotomized cadaveric scaphoids. Two novel prototype BSS, oblique type (BSS-obl.) and longitudinal type (BSS-long.) were compared to three conventional screws: Acutrak2®mini, HCS®3.0 and Twinfix®. Biomechanical tests were performed on scaphoids from single donors in paired comparison and analyzed by balanced incomplete random block design. Loading was increased by 50 mNm increments with 1,000 cycles per torque level and repeated until a rotational clearance of 10°. Primary outcome measure was the number of cycles to 10° clearance, secondary outcome measure was the maximum rotational clearance for each torque level. Findings BSS-obl. performed significantly better than Acutrak2®mini and HCS® (p = 0.015, p<0.0001). BSS-long. performed significantly better than HCS® (p = 0.010). No significant difference in performance between BSS-obl. and BSS-long. (p = 0.361), between BSS obl. and Twinfix® (p = 0.50) and BSS long. and Twinfix® (p = 0.667) was detected. Within the torque range up to 200 mNm, four of 21 (19%) BSS-long. and four of 21 (19%) BSS-obl. preparations showed early failure. The same loading led to early failure in four (29%) Twinfix®, seven (50%) Acutrak2®mini and 10 (71%) HCS® of 14 screw samples, respectively. Conclusions For both BSS and to a lesser extent for Twinfix® (as dual-component screw

  11. Scaphocapitate Fracture: Two Cases with Follow-Up over 5 Years

    PubMed Central

    Dailiana, Zoe H.; Papatheodorou, Loukia K.; Malizos, Konstantinos N.

    2015-01-01

    Background Combined scaphoid and capitate fractures of the wrist are rare entities, and delayed diagnosis is frequent. Scaphocapitate fractures may be associated with reversal of the capitate head 90° or 180° (Fenton syndrome). Different treatment options have been proposed, with variable results. Case Description We report two cases of scaphocapitate fractures of the wrist, diagnosed 3 and 15 days after the injury. The first patient suffered from Fenton syndrome, a combined displaced fracture of the waist of the scaphoid with 180° reversal of capitate head. The second patient had combined fractures of the scaphoid, capitate, and distal radius. In both our cases, anatomic reduction and internal fixation were achieved, resulting in union of all fractures. The long-term results, after 5.5 and 7 years respectively, were very satisfactory, both clinically and radiographically, without signs of avascular necrosis of the head of the capitate or the scaphoid. Literature Review Few reports of scaphocapitate fractures were found in literature. Mechanism of injury, treatment, and outcomes of the reported cases in correlation to our cases are discussed. Clinical Relevance Given the high rate of complications of scaphocapitate fractures, long-term follow-up is important to assess the natural history of the wrist joint after such injuries. The restoration of normal anatomic relationships can lead to a successful long-term functional outcome despite the severity of the injury. PMID:26261742

  12. Concomitant avascular necrosis of the scaphoid and lunate.

    PubMed

    Bhardwaj, Praveen; Sharma, Chetna; Sabapathy, S Raja

    2012-01-01

    Simultaneous avascular necrosis of multiple carpal bones is rare. Concomitant avascular necrosis of scaphoid and lunate has been reported only once. We report one more case of this rare condition which can be a cause of wrist pain. Steroid intake is a known risk factor for avascular necrosis but in our case the patient had been taking herbal medicines for joint pain the composition of which was not known. Probably the presence of steroid in these medicines was the cause of avascular necrosis in this case.

  13. Human scaphoid non-unions exhibit increased osteoclast activity compared to adjacent cancellous bone.

    PubMed

    Schira, Jessica; Schulte, Matthias; Döbele, Carmen; Wallner, Christoph; Abraham, Stephanie; Daigeler, Adrien; Kneser, Ulrich; Lehnhardt, Marcus; Behr, Björn

    2015-12-01

    Scaphoid bones have a high prevalence for non-union. Even with adequate treatment, bone regeneration may not occur in certain instances. Although this condition is well described, the molecular pathology of scaphoid non-unions is still poorly defined. In this study, gene expression of osteogenic and angiogenic growth and transcription factors as well as inflammatory mediators were analysed in human scaphoid non-unions and intraindividually compared to adjacent autologous cancellous bone from the distal radius. In addition, histology and immunohistochemical stainings were performed to verify qRT-PCR data. Gene expression analysis revealed a significant up-regulation of RANKL, ALP, CYCLIN D1, MMP-13, OPG, NFATc1, TGF-β and WNT5A in scaphoid non-unions. Interestingly, RANKL and NFATc1, both markers for osteoclastogenesis, were significantly induced in non-unions. Moreover, WNT5A was highly up-regulated in all non-union samples. TRAP staining confirmed the observation of induced osteoclastogenesis in non-unions. With respect to genes related to osteogenesis, alkaline phosphatase was significantly up-regulated in scaphoid non-unions. No differences were detectable for other osteogenic genes such as RUNX-2 or BMP-2. Importantly, we did not detect differences in angiogenesis between scaphoid non-unions and controls in both gene expression and immunohistochemistry. Summarized, our data indicate increased osteoclast activity in scaphoid non-unions possibly as a result of the alterations in RANKL, TGF-β and WNT5A expression levels. These data increase our understanding for the reduced bone regeneration capacity present in scaphoid non-unions and may translate into the identification of new therapeutic targets to avoid secondary damages and prevent occurrence of non-unions to scaphoid bones. © 2015 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  14. Measurement of stellar occultations

    NASA Astrophysics Data System (ADS)

    Eberle, Andreas

    2008-09-01

    Whenever an asteroid occults a star, we have the opportunity to study that asteroid in great detail. As frequently shown in the past, amateur astronomers1 have the necessary equipment to measure such events successfully2. Combined with the dense net of amateur observatories and online coordination tools3 for movable stations, they can create fine grids to detect even small bodies. The analysis of these events gives us the possibility to receive high precision astrometry data, to determine the asteroids size and shape (and therefore its albedo), and even to collect information on the star itself.4 While usually a set of several light curves is required to do so, a single recording5 of (10734) Wieck's occultation of HIP 22157 on 2008 Feb 08 was sufficient to retrieve the necessary data6. 1 Observation campaigns are organized by the International Occultation Timing Association (IOTA), http://www.iota-es.de/ 2 for results see e.g. euraster.net by E. Frappa, http://www.euraster.net/ 3 Occult Watcher by H. Pavlov, http://www.hristopavlov.net/OccultWatcher/OccultWatcher.html 4 see K. Miyashita's analysis of the observation of the occultation of TYC 1886-01206-1 by Kalliope and Linus, http://www005.upp.so-net.ne.jp/k miyash/occ02/kalliope/doublestar en.html 5 recording obtained by H. Michels, MPC Station Code 240 6 using Limovie by K. Miyashita

  15. Fractures

    MedlinePlus

    A fracture is a break, usually in a bone. If the broken bone punctures the skin, it is called an open ... falls, or sports injuries. Other causes are low bone density and osteoporosis, which cause weakening of the ...

  16. Complete dorsal dislocation of the carpal scaphoid with perilunate dorsal dislocation

    PubMed Central

    Kang, Jong Woo; Park, Jong Hoon; Suh, Dong Hun; Park, Jong Woong

    2016-01-01

    Complete dorsal dislocation of the carpal scaphoid combined with dorsal perilunate dislocation is an extremely rare carpal injury. We describe the case of a 23-year-old man who presented with a complete dorsal dislocation of the carpal scaphoid, combined with a perilunate dislocation. Surgical treatment was performed with open reduction and interosseus ligament repair. At 4 years follow up, the patient's wrist pain had completely resolved without limitations of wrist joint motion and without evidence of avascular necrosis of the carpal scaphoid. PMID:27512229

  17. Occulter Starshade Technology Development

    NASA Astrophysics Data System (ADS)

    Lisman, P. D.; Thomson, M.; Kissil, A.; Walkemeyer, P.; Polanco, O.

    2010-10-01

    Imaging Earth-like exoplanets with a free flying occulter requires developing a large, lightweight, flower-shaped, deployable structure with precisely controlled edge position and profile. In-plane tolerance requirements are considerably tighter than heritage antenna systems, but the more difficult to control out-of-plane tolerances are actually much looser. This paper presents a novel occulter mechanical design that delivers the required performance with a highly reliable deployment scheme. A very compact stowed volume is an added benefit that enables launching the occulter together with a 1 to 2m class telescope, using a single, currently available launch vehicle. Demonstrating the petal deployment function and compliance with key tolerance specifications is the focus of current technology efforts. A series of prototype models of increasing fidelity are planned, starting with a proof of concept model that is currently in fabrication. The occulter design and current development status is presented herein.

  18. Scaphoid tuberosity excursion is minimized during a dart-throwing motion: A biomechanical study.

    PubMed

    Werner, Frederick W; Sutton, Levi G; Basu, Niladri; Short, Walter H; Moritomo, Hisao; St-Amand, Hugo

    2016-01-01

    The purpose of this study was to determine whether the excursion of the scaphoid tuberosity and therefore scaphoid motion is minimized during a dart-throwing motion. Scaphoid tuberosity excursion was studied as an indicator of scaphoid motion in 29 cadaver wrists as they were moved through wrist flexion-extension, radioulnar deviation, and a dart-throwing motion. Study results demonstrate that excursion was significantly less during the dart-throwing motion than during either wrist flexion-extension or radioulnar deviation. If the goal of early wrist motion after carpal ligament or distal radius injury and reconstruction is to minimize loading of the healing structures, a wrist motion in which scaphoid motion is minimal should reduce length changes in associated ligamentous structures. Therefore, during rehabilitation, if a patient uses a dart-throwing motion that minimizes his or her scaphoid tuberosity excursion, there should be minimal changes in ligament loading while still allowing wrist motion. Bench research, biomechanics, and cross-sectional. Not applicable. The study was laboratory based. Copyright © 2016 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

  19. Occultation by (136199) Eris

    NASA Astrophysics Data System (ADS)

    Jehin, E.; Manfroid, J.; Gillon, M.; Hutsemekers, D.; Magain, P.

    2010-11-01

    E. Jehin, J. Manfroid, M. Gillon, D. Hutsemekers, and P. Magain report that they observed an occultation of a star of magnitude I about 15.2 by the dwarf planet Eris (then at V about 18.7) on Nov. 6 using the new telescope TRAPPIST at the European Southern Observatory (La Silla). A series of 3-s exposures of a field of size 3' x 3' (1".3/pixel) were secured in fast-readout mode (with a deadtime of 1.5 s), starting at 01h50m UT for one hour. Seven frames centered at 02h19m34s UT allowed them to derive the start of the occultation as 02h19m16s.75 +/- 0s.75 and the end as 02h19m47s.6 +/- 0s.2, for a total occultation time of 30.4 +/- 1.0 seconds. The predictions (see above) made by the Rio de Janeiro group (Assafin et al., Nov. 5) and by J. L. Ortiz estimated the time of the occultation around 02h18m UT for Chile, in good agreement with the observations. During the occultation, a point source is detected with a magnitude corresponding to that of Eris. A small flux increase was also seen at the middle of the occultation, which might result from refraction in Eris' atmosphere (Elliot and Olkin 1996, Ann. Rev. Earth Planet. Sci. 24, 89). Eris is by far the most-remote solar-system object observed to date via stellar occultation, with a geocentric distance of about 96 AU. TRAPPIST is a project driven by the University of Liege, in close collaboration with the Observatory of Geneva, supported by the Belgian Fund for Scientific Research and the Swiss National Science Foundation.

  20. Pediatric Hand Fractures

    PubMed Central

    Nellans, Kate W.; Chung, Kevin C.

    2014-01-01

    Summary Pediatric hand fractures are common childhood injuries. Identification of the fractures in the emergency room setting can be challenging owing to the physes and incomplete ossification of the carpus that are not revealed in the xrays. Most simple fractures can be treated with appropriate immobilization through buddy taping, finger splints, or casting. If correctly diagnosed, reduced and immobilized, these fractures usually result in excellent clinical outcomes. However, fractures may require operative stabilization if they have substantial angulation or rotation, extend into the joint, or cannot be held in a reduced position with splinting alone. Most fractures can be treated operatively with closed reduction and percutaneous pinning if addressed within the first week following the injury. In children, the thick, vascular-rich periosteum and bony remodeling potential make anatomic reductions and internal fixation rarely necessary. Most fractures complete bony healing in 3-4 weeks, with the scaphoid being a notable exception. Following immobilization, children rarely develop hand stiffness and formal occupational therapy is usually not necessary. Despite the high potential for excellent outcomes in pediatric hand fractures, some fractures remain difficult to diagnose and treat. PMID:24209954

  1. Occultations, past and future

    NASA Astrophysics Data System (ADS)

    Evans, David S.

    Techniques and limitations of photoelectric observations of occultations are discussed. Methods are described for allowing for fringe effects which arise from real world deviations from a uniform limb, and for using the limb measurements to derive ephemerides for the moon. Procedures employed to identify and separate out the components of multiple star systems are reviewed, and techniques are presented for improving the acuity of photoelectric angular size measurements that are complementary to interferometric measurements. Finally, sample data are provided to illustrate anomalies observed in photoelectric occultation observations of Antares and Aldebaran.

  2. All about Occultation.

    ERIC Educational Resources Information Center

    Riddle, Bob

    2001-01-01

    Describes occultation events involving the moon, when the moon blocks the view of planets or stars. Describes other events such as a partial solar eclipse, a penumbral lunar eclipse, meteor showers, and moon phases. Provides a list of internet resources related to these events. (DLH)

  3. All about Occultation.

    ERIC Educational Resources Information Center

    Riddle, Bob

    2001-01-01

    Describes occultation events involving the moon, when the moon blocks the view of planets or stars. Describes other events such as a partial solar eclipse, a penumbral lunar eclipse, meteor showers, and moon phases. Provides a list of internet resources related to these events. (DLH)

  4. The Scaphoid Safe Zone: A Radiographic Simulation Study to Prevent Cortical Perforation Arising from Different Views

    PubMed Central

    Chang, Biao; Liu, Ruoxi; Zhu, Yun; Peng, Jiang; Zhao, Qing; Lu, Shibi

    2017-01-01

    Purpose The purpose of this study was to simulate and calculate the probability of iatrogenic perforation of the scaphoid cortical bone when internal fixation appeared to be safe on radiographs. The results will assist surgeons in determining proper screw placement. Methods Thirty scaphoids were reconstructed using computed tomography data and image-processing software. Different central axes were determined by the software to simulate the surgical views. The safe zone (SZ) and risk zone (RZ) were identified on the axial projection radiographs by comparing the scaphoid bone stenosis measured by the fluoroscopic radiographs with a three-dimensional reconstruction of the scaphoid stenosis. Each original axial projection radiograph was zoomed and compiled to match a calculated average image. The RZ, SZ, and probability of perforations in various quadrants were calculated. Results Using a volar view (approach), the mean risks of cortical perforation were 25% with screws and 36% with k-wires. Using a dorsal view (approach), the mean risks of cortical perforation were 18% with screws and 30% with k-wires. A high risk of perforation was detected at the ulnar–dorsal zone. Conclusion Surgeons should be wary of screws that appear to lie close to the scaphoid cortex on both anteroposterior (AP) and lateral radiographs, particularly in the ulnar–dorsal and radial–dorsal quadrants, because such screws are likely to perforate the cortex. The position of the internal fixator should be assessed using a diagram outlining the various SZs. Therapeutic, Level III. PMID:28114317

  5. Scaphoid reconstruction by a free vascularized osteochondral graft from the rib: a case report.

    PubMed

    Lanzetta, Marco

    2009-01-01

    Nonunion and avascular necrosis of the proximal pole of the scaphoid remain one of the most difficult problems in wrist reconstructive surgery. A number of interpositional vascularized bone grafts have been proposed for scaphoid nonunion, in order to promote faster union at the contact site with both fragments. However, once the proximal pole has undergone avascular changes and is completely necrotic, there is no alternative other than to remove it. At present, more radical operations have been advocated in these cases, such as proximal row carpectomy or intercarpal arthrodesis. We present a case where the necrotic proximal pole of the scaphoid was removed and replaced with a remodeled osteochondral-free vascularized graft from the rib based on the inferior and superior intercostal arteries, branches of the internal mammary artery.

  6. Isolated scaphotrapeziotrapezoid osteoarthritis treatment using resurfacing arthroplasty with scaphoid anchorage.

    PubMed

    Humada Álvarez, G; Simón Pérez, C; García Medrano, B; Faour Martín, O; Marcos Rodríguez, J J; Vega Castrillo, A; Martín Ferrero, M A

    2017-09-07

    The aim of this study is to show the results of scaphotrapeziotrapezoid (STT) joint osteoarthritis treatment performing resurfacing arthroplasty with scaphoid anchorage. An observational, descriptive and retrospective study was performed. Ten patients with isolated STT joint osteoarthritis were studied between 2013 and 2015. The mean follow-up time was 26months. Clinical results, functional and subjective scores were reviewed. The patients were satisfied, achieving an average of 2.1 (0-3) on the VAS score and 16 (2 to 28) in the DASH questionnaire, and returning to work in the first three months post-surgery. Recovery of range of motion compared to the contralateral wrist was 96% in extension, 95% in flexion, 87% in ulnar deviation and 91% in radial deviation. The average handgrip strength of the wrist was 95% and pinch strength was 95% compared to the contralateral side. There were no intraoperative complications or alterations in postoperative carpal alignment. Resurfacing arthroplasty is proposed as a good and novel alternative in treating isolated SST joint arthritis. Achieving the correct balance between the strength and mobility of the wrist, without causing carpal destabilisation, is important to obtain satisfactory clinical and functional results. Copyright © 2017. Publicado por Elsevier España, S.L.U.

  7. Salvage of a post-traumatic arthritic wrist using the scaphoid as an osteochondral graft.

    PubMed

    Marcuzzi, A; Ozben, H; Russomando, A

    2014-09-01

    The authors describe a case of post-traumatic wrist arthritis with an osteochondral defect in the scaphoid fossa of the radius. The patient was treated with proximal row carpectomy, radial styloidectomy and reconstruction of the defect using the proximal half of the scaphoid as an autologous osteochondral graft. Pain relief was achieved while wrist motion and strength were improved. The carpal bones are a source of osteochondral grafts and can be used to expand the indications of motion-preserving wrist salvage procedures.

  8. The Pinhole/Occulter Facility

    NASA Technical Reports Server (NTRS)

    Tandberg-Hanssen, E. A. (Editor); Hudson, H. S. (Editor); Dabbs, J. R. (Editor); Baity, W. A. (Editor)

    1983-01-01

    Scientific objectives and requirements are discussed for solar X-ray observations, coronagraph observations, studies of coronal particle acceleration, and cosmic X-ray observations. Improved sensitivity and resolution can be provided for these studies using the pinhole/occulter facility which consists of a self-deployed boom of 50 m length separating an occulter plane from a detector plane. The X-ray detectors and coronagraphic optics mounted on the detector plane are analogous to the focal plane instrumentation of an ordinary telescope except that they use the occulter only for providing a shadow pattern. The occulter plane is passive and has no electrical interface with the rest of the facility.

  9. The effect of ultrasound on the healing of muscle-pediculated bone graft in scaphoid non-union.

    PubMed

    Ricardo, Monreal

    2006-04-01

    The use of pedicled vascularised bone grafts from the distal radius makes it possible to transfer bone with a preserved circulation and viable osteoclasts and osteoblasts. Experiments performed at the basic science level has provided substantial evidence that low-intensity ultrasound can accelerate and augment the fracture healing process. Only an adequate double-blind trial comparing treatment by ultrasound stimulation in patients treated by similar surgical techniques can provide evidence of the true effect of ultrasound. This paper describes the results of such a trial. From 1999 to 2004, 21 fractures of the scaphoid with established non-union treated with vascularised pedicle bone graft were selected for inclusion in a double-blind trial. All patients were males, with an average age of 26.7 years (range 17-42 years) and an average interval between injury and surgery of 38.4 months (range 3 months-10 years). Low-intensity ultrasound was delivered using a TheraMed 101-B bone-growth stimulator (30 mW/cm2, 20 min/day), which was modified to accomplish double-blinding. These modifications did not affect the designated active units. The placebo units were adjusted to give no ultrasound signal output across the transducer. Externally, all units appeared identical but were marked with individual code numbers. Patients were randomly allocated to either an active or placebo stimulation. Follow-up averaged 2.3 years (range 1-4 years). All patients achieved fracture union (active and placebo groups), but compared with the placebo device (11 patients), the active device (ten patients) accelerated healing by 38 days (56+/-3.2 days compared with 94+/-4.8 days, p<0.0001, analysis of variance).

  10. Lunar occultation angular diameter measurements.

    NASA Astrophysics Data System (ADS)

    Beavers, W. I.; Eitter, J. J.; Dunham, D. W.; Stein, W. L.

    1980-11-01

    The analysis of one dozen lunar occultation diameter candidate observations are reported. Within this set of occultation measurements at Fick Observatory, six of the stars provide sensible angular diameters, and the remainder appear as virtual point sources. Angular diameter measurements are reported for ɛ Gem, BD+24°0571, υ Cap, R Gem, and BD+23°1518.

  11. Photoelectric observations of lunar occultations

    NASA Technical Reports Server (NTRS)

    Fekel, F. C.; Montemayor, T. J.; Barnes, T. G., III; Moffett, T. J.

    1980-01-01

    Photoelectric observations of 13 lunar occultation disappearances during a March 1979 Hyades passage are reported. Three double stars (SAO 93925 = Fin 342 = 70 Tau, SAO 93961 = ADS 3248, and SAO 95419 = Kui 24) and one possible double (SAO 93950 = 75 Tau) were detected. A brief description is given of the Purdue University pulse-counting photometer as modified for occultation observations.

  12. Total volar extrusion of the lunate and scaphoid proximal pole with concurrent scapholunate dissociation.

    PubMed

    Koh, Kyoung Hwan; Lim, Tae Kang; Park, Min Jong

    2012-09-01

    This article describes a case of a 24-year-old man with a total volar extrusion of the lunate and scaphoid proximal pole with concurrent scapholunate dissociation. The viability of the lunate and the proximal pole of the scaphoid are at high risk in this type of injury. Scaphoid nonunion, avascular necrosis of the lunate and proximal pole of the scaphoid, and carpal instability are inevitable unless the blood supply is restored. Thus, proximal row carpectomy at injury may be an acceptable option to avoid these complications and late sequelae, including chronic wrist pain and dysfunction. However, the authors attempted accurate reduction of the extruded bones and internal fixation.Final radiographs and magnetic resonance imaging 12 years postoperatively showed healing without avascular necrosis. Carpal indices involving the scapholunate angle, radiolunate angle, and carpal height ratio were similar in both wrists without evidence of carpal instability or collapse. Range of motion and grip power were 75% and 76%, respectively, compared with those of the uninjured wrist. Clinical scores showed good results, and the patient reported no pain during activities of daily living and was satisfied with his surgical results. Open reduction and internal fixation can be a viable option in this rare pattern of injury.

  13. The Halogen Occultation Experiment

    NASA Technical Reports Server (NTRS)

    Russell, James M., III; Gordley, Larry L.; Park, Jae H.; Drayson, S. R.; Hesketh, W. D.; Cicerone, Ralph J.; Tuck, Adrian F.; Frederick, John E.; Harries, John E.; Crutzen, Paul J.

    1993-01-01

    The Halogen Occultation Experiment (HALOE) uses solar occultation to measure vertical profiles of O3, HCl, HF, CH4, H2O, NO, NO2, aerosol extinction, and temperature versus pressure with an instantaneous vertical field of view of 1.6 km at the earth limb. Latitudinal coverage is from 80 deg S to 80 deg N over the course of 1 year and includes extensive observations of the Antarctic region during spring. The altitude range of the measurements extends from about 15 km to about 60-130 km, depending on channel. Experiment operations have been essentially flawless, and all performance criteria either meet or exceed specifications. Internal data consistency checks, comparisons with correlative measurements, and qualitative comparisons with 1985 atmospheric trace molecule spectroscopy (ATMOS) results are in good agreement. Examples of pressure versus latitude cross sections and a global orthographic projection for the September 21 to October 15, 1992, period show the utility of CH4, HF, and H2O as tracers, the occurrence of dehydration in the Antarctic lower stratosphere, the presence of the water vapor hygropause in the tropics, evidence of Antarctic air in the tropics, the influence of Hadley tropical upwelling, and the first global distribution of HCl, HF, and NO throughout the stratosphere. Nitric oxide measurements extend through the lower thermosphere.

  14. The occult urothelial cancer.

    PubMed

    Ragonese, Mauro; Racioppi, Marco; D'Agostino, Daniele; Di Gianfrancesco, Luca; Lenci, Niccolò; Bientinesi, Riccardo; Palermo, Giuseppe; Sacco, Emilio; Pinto, Francesco; Bassi, Pier Francesco

    2016-05-24

    Transitional cell carcinoma (TCC) is the tumor that most frequently affects the urinary tract. The most common location is in the bladder; the diagnosis, as the follow-up, is based on urine cytology, endoscopic, and radiological examinations. Urinary cytology is an important non invasive tool used in the diagnosis and follow-up of patients with TCC. A positive urine cytology result is highly predictive of the presence of TCC, even in the presence of normal cystoscopy, because malignant cells may appear in the urine long time before any cystoscopically visible lesion becomes apparent. The presence of a positive urinary cytology, in the absence of clinical or endoscopic evidence of a TCC, can identify an occult urothelial cancer, located in any site of the urinary tract (upper urinary tract, bladder, prostatic urethra). Most of the urothelial tumors of the renal pelvis and ureters are diagnosed by radiological examinations, but we can observe a high rate of false negatives. In order to improve the diagnostic role of urinary cytology and other conventional examinations, numerous molecular markers have been identified; however, the real clinical application remains unclear. Photodynamic diagnosis and narrow band imaging (NBI) cystoscopy increase the diagnostic accuracy of endoscopic examinations in the presence of lesions not easily detectable. The aim of this review is to analyze the current diagnostic standards in the presence of occult urothelial cancer.

  15. The Halogen Occultation Experiment

    NASA Technical Reports Server (NTRS)

    Russell, James M., III; Gordley, Larry L.; Park, Jae H.; Drayson, S. R.; Hesketh, W. D.; Cicerone, Ralph J.; Tuck, Adrian F.; Frederick, John E.; Harries, John E.; Crutzen, Paul J.

    1993-01-01

    The Halogen Occultation Experiment (HALOE) uses solar occultation to measure vertical profiles of O3, HCl, HF, CH4, H2O, NO, NO2, aerosol extinction, and temperature versus pressure with an instantaneous vertical field of view of 1.6 km at the earth limb. Latitudinal coverage is from 80 deg S to 80 deg N over the course of 1 year and includes extensive observations of the Antarctic region during spring. The altitude range of the measurements extends from about 15 km to about 60-130 km, depending on channel. Experiment operations have been essentially flawless, and all performance criteria either meet or exceed specifications. Internal data consistency checks, comparisons with correlative measurements, and qualitative comparisons with 1985 atmospheric trace molecule spectroscopy (ATMOS) results are in good agreement. Examples of pressure versus latitude cross sections and a global orthographic projection for the September 21 to October 15, 1992, period show the utility of CH4, HF, and H2O as tracers, the occurrence of dehydration in the Antarctic lower stratosphere, the presence of the water vapor hygropause in the tropics, evidence of Antarctic air in the tropics, the influence of Hadley tropical upwelling, and the first global distribution of HCl, HF, and NO throughout the stratosphere. Nitric oxide measurements extend through the lower thermosphere.

  16. [Unilateral congenital absence of the carpal scaphoid associated with dysplasia of the capitate. Presentation of a case].

    PubMed

    Gómez Fernández, J M; Méndez López, J M; Caracuel Redondo, F

    2012-01-01

    We report on a case of aplasia or unilateral congenital absence of the carpal scaphoid associated with dysplasia of the capitate. Congenital absence of the carpal scaphoid is a rare but well-documented condition. As far as we know, the present case is the seventh one reported in the medical literature. Imaging studies (X-ray and MRI) confirmed the absence of the carpal scaphoid associated with a dysplasia of the capitate and malformation of the radial styloid process. Congenital absence of the scaphoid when other congenital abnormalities (such as hypoplasia or aplasia of either forearm bones or thenar eminence, malformations of the skeletal elements of the thumb, absence of sesamoid bones or abnormal development of the forearm bones) do not exist is probably the main feature of the present case report. Copyright © 2011 SECOT. Published by Elsevier Espana. All rights reserved.

  17. [Diagnostically Approach to Pediatric Carpal Fractures: a Retrospective Analysis].

    PubMed

    Eckert, K; Tröbs, R-B; Schweiger, B; Liedgens, P; Radeloff, E; Ackermann, O

    2016-02-01

    Carpal fractures in children are rare, but can be missed, as their clinical symptoms are unspecific and discrete. Even X-ray diagnosis is difficult. Timely diagnosis and consistent therapy are especially important for scaphoid fractures, as they can help to avoid complications such as non-union or avascular necrosis. A diagnostic approach to paediatric carpal fractures will be discussed on the basis of the following group of patients. Retrospective analysis of children under 14 years treated in our institution between 09/2010 and 02/2012 for clinically suspected carpal fracture. In the primary evaluation, all children underwent standard X-rays of the hand and/or wrist. All patients were treated by cast immobilisation until complete clinical recovery. All patients with clinical signs of carpal fracture were treated by cast immobilization, even with normal X-rays. The clinical follow-up examination was after 10 to 14 days. In patients with persistent complaints, MRI was performed. We retrospectively evaluated the records of all patients: the fractured carpal bone, and X-ray and MRI-diagnosis were stated. We calculated the mean difference between first presentation and MRI and the mean period for total recovery, in patients with fracture or non-fracture. 61 children (27 boys and 34 girls, mean age 11.5 y) were included in our study. The mean delay between accident and time of first presentation to our paediatric ED was 0.6 days. In primary X-rays, a carpal fracture was demonstrated in only in 2 (3.3 %) patients, but was suspected in only 6 (9.8 %) of patients. In 53 (87.9 %) patients, there was no radiographic evidence of carpal fracture. 14 patients underwent additional scaphoid views, but scaphoid fracture was confirmed in only 1 (7 %) of these patients. In 3 (21.4 %) patients, a scaphoid fracture was suspected and in 10 patients a carpal fracture could be excluded. After a mean time of 11.8 days, all patients underwent a clinical follow-up examination

  18. Pinhole occulter experiment

    NASA Technical Reports Server (NTRS)

    Ring, Jeff; Pflug, John

    1987-01-01

    Viewgraphs and charts from a briefing summarize the accomplishments, results, conclusions, and recommendations of a feasibility study using the Pinhole Occulter Facility (POF). Accomplishments for 1986 include: (1) improved IPS Gimbal Model; (2) improved Crew Motion Disturbance Model; (3) use of existing shuttle on-orbit simulation to study the effects of orbiter attitude deadband size on POF performance; (4) increased understanding of maximum performance expected from current actuator/sensor set; (5) use of TREETOPS nonlinear time domain program to obtain system dynamics describing the complex multibody flexible structures; (6) use of HONEY-X design tool to design and evaluate multivariable compensator for stability, robustness, and performance; (7) application of state-of-the-art compensator design methodology Linear Quadratic Gaussian/Loop Transfer Recovery (LQG/LTR); and (8) examination of tolerance required on knowledge of the POF boom flexible mode frequencies to insure stability, using structure uncertainty analysis.

  19. Alice Solar Occultation

    NASA Image and Video Library

    2015-07-17

    This figure shows how the Alice instrument count rate changed over time during the sunset and sunrise observations. The count rate is largest when the line of sight to the sun is outside of the atmosphere at the start and end times. Molecular nitrogen (N2) starts absorbing sunlight in the upper reaches of Pluto's atmosphere, decreasing as the spacecraft approaches the planet's shadow. As the occultation progresses, atmospheric methane and hydrocarbons can also absorb the sunlight and further decrease the count rate. When the spacecraft is totally in Pluto's shadow the count rate goes to zero. As the spacecraft emerges from Pluto's shadow into sunrise, the process is reversed. By plotting the observed count rate in the reverse time direction, it is seen that the atmospheres on opposite sides of Pluto are nearly identical. http://photojournal.jpl.nasa.gov/catalog/PIA19716

  20. Occult Fungal Scleritis

    PubMed Central

    Jeang, Lauren J.; Davis, Aaron; Madow, Brian; Espana, Edgar M.; Margo, Curtis E.

    2017-01-01

    Purpose To heighten awareness of occult fungal scleritis. Method Case report and review of the literature. Results A 73-year-old woman with diabetes mellitus was diagnosed for 3 months with immune-mediated scleritis and subsequently treated with corticosteroids. On referral, the patient had a scleral nodule with contiguous corneal infiltrate and hypopyon. Culture grew Fusarium species not further classified. The infection could not be controlled with antifungal therapy, and the eye was removed. No exogenous or endogenous source for the infection could be identified by clinical history or examination. Conclusion Fungal scleritis can develop in persons without a history of foreign body injury, minor trauma, or evidence of endogenous fungemia. A high index of suspicion for infectious scleritis must be maintained in persons with presumed immune-mediated scleritis who fail to respond to conventional therapy, particularly if they present with decreased visual acuity. PMID:28275602

  1. Case of bilateral Galeazzi fractures associated with dislocation of the right elbow.

    PubMed

    Nanno, Mitsuhiko; Sawaizumi, Takuya; Takai, Shinro

    2011-01-01

    We report an unusual case of bilateral Galeazzi fractures associated with dislocation of the right elbow and fracture of the right scaphoid caused by a motorbike accident in a 32-year-old man. Bilateral radiuses were fixed with plates, and the right scaphoid was fixed with a screw after closed reduction of the right elbow. A satisfactory result was obtained with a return to work and no radiographic problems 7 years after surgery. The mechanism of the injury was thought to be a high-velocity fall on the outstretched hands combined with extreme pronation of the forearms and extension of the wrists and the elbows. This case had a favorable outcome following operative stabilization of the fracture-dislocations and early mobilization.

  2. KPNO LUNAR OCCULTATION SUMMARY. III

    SciTech Connect

    Schmidtke, P. C.; Africano, J. L.

    2011-01-15

    The results for 251 lunar occultation events recorded at Kitt Peak National Observatory are presented, including 20 observations of known or suspected double stars and five measurements of stars with resolved angular diameters.

  3. Modern Asteroid Occultation Observing Methods

    NASA Astrophysics Data System (ADS)

    Lucas, G. A.

    2004-05-01

    This presentation reviews current working methods for asteroid occultations developed by the International Occultation Timing Association (IOTA). Reduc- tion of multiple tracks or "chords" observed during stellar occultations pro- vides valuable measures of the relative sizes and shapes of asteroids. Tradi- tionally, predictions for asteroid occultations were prepared by regional IOTA computors, distributed annually in "hard copy" format to IOTA subscrib- ers and in publications such as Sky & Telescope magazine and the annual RASC Observers Handbook. IOTA - like many other organizations - is now using worldwide internet services and e-mail to distribute frequently-updated pre- dictions based upon the latest astrometry. The IOTA web pages provide an easily accessible, centralized source of information on lunar and solar sys- tem occultation events. IOTA's web pages feature a variety of articles on current activities, plans for observing campaigns and expeditions, and "how to do it" information on the latest technology and techniques. The latest up- dated predictions for asteroid events are made available as they are pro- duced, providing more accurate observing tracks and efficient coordination of observers. The IOTA e-mail list provides a dynamic forum for the exchange of technical information and com-munication of observing plans in a timely man- ner. Individuals may now generate customized occultation predictions using the WinOccult software package. The author presents some examples of recent occultation events, showing the benefits of coordinated observations. Also described are some of the latest innovations, featuring low-cost video camera equipment, devices for time insertion based on Global Positioning Satellite (GPS) technology, and a new approach using unattended secondary field station equipment to multiply the number of tracks observed.

  4. [Occult hepatitis C virus infection].

    PubMed

    Carreño García, Vicente; Nebreda, Javier Bartolomé; Aguilar, Inmaculada Castillo; Quiroga Estévez, Juan Antonio

    2011-03-01

    Occult hepatitis C virus (HCV) infection is characterized by the detection of HCV-RNA in liver in the absence of anti-HCV and serum HCV-RNA determined by conventional techniques. The development of a new enzyme immunoassay for the detection of antibodies against a conserved epitope in the HCV core protein, together with the detection of HCV-RNA in peripheral blood mononuclear cells and in serum after concentrating the viral particles by ultracentrifugation, allow diagnosis of more than 90% of patients with occult HCV without the need to perform a liver biopsy. Histological damage in occult HCV infection ranges from minimal changes to liver cirrhosis and hepatocellular carcinoma, although in general this disease is less severe than classical chronic hepatitis C. A significant prevalence of occult HCV infection has been identified in risk groups such as hemodialysis patients and the family members of patients with occult hepatitis C. This occult HCV infection can also be found in subjects without clinical or biochemical evidence of liver disease. Copyright © 2011 Elsevier España S.L. All rights reserved.

  5. Intraosseous Ganglion Cyst of Scaphoid: An Uncommon Cause of Radial Wrist Pain.

    PubMed

    Salunke, Abhijeet Ashok; Singh, Saranjeet; Kanani, Himanshu; Chokshi, Jimmy; Nambi, G I; Raval, Pradyumna; Vala, Pathik; Jain, Shantanu; Chaudhari, Sanjay; Patel, Amit; Panchal, Ramesh

    2016-02-01

    Intraosseous ganglion cyst is a rare bone tumor and the lesion could often be missed. The diagnosis could be delayed so proper radiologic investigation and index of suspicion is necessary .Differential diagnoses of painful cystic radiolucent carpal lesion are osteoid osteoma, osteoblastoma and intraosseous ganglion. Curettage of the scaphoid lesion and filling of void with bone graft provides good functional outcomes. The cyst contains mucoid viscous material without epithelial or synovial lining. We present a case of 30 years old male with intraosseous ganglion cyst of scaphoid which was treated with curettage and bone grafting. Rarely ganglion cyst is found in small bones of hand and should be considered as differential diagnosis of chronic radial wrist pain.

  6. The arthroscopic treatment of avascular necrosis of the proximal pole following scaphoid nonunion.

    PubMed

    Ruch, D S; Chang, D S; Poehling, G G

    1998-10-01

    The authors describe a technique of treating scaphoid nonunions with associated avascular necrosis consisting of arthroscopic resection of the distal pole of the scaphoid combined with radial styloidectomy. The results at 2-year follow-up showed all three patients to have complete relief of their mechanical pain and improvement in their range of motion as well as high satisfaction with the procedure. Modified Mayo Wrist Scores were a mean preoperatively of 60 and postoperatively of 88. Postoperative radiographs showed no increase in the scapholunate gap. However, the capitolunate angle increased from a mean of 3 degrees to 13 degrees . There was no progression of degenerative changes noted. The advantages of this technique include (1) minimal morbidity, (2) relief of mechanical pain, and (3) improved range of motion with no early degenerative changes. The rate and severity of degenerative change following this procedure remain unknown.

  7. TREATMENT OF SCAPHOID NONUNION WITH OLECRANON BONE GRAFT AND COMPRESSION SCREW

    PubMed Central

    NEDER, ANTONIO TUFI; FRANCESCHINI, EDUARDO TRALDI; PARDINI, ARLINDO GOMES; RIBERTO, MARCELO; MAZZER, NILTON

    2016-01-01

    ABSTRACT Objective: To evaluate the outcome of olecranon bone graft and compression screw for the treatment of nonunion of the Lichtman type I scaphoid. Method: We evaluated 15 patients of 32 who underwent surgical treatment for nonunion of the Lichtman type I scaphoid with olecranon bone graft and screw compression. Results: We obtained 100% consolidation in our sample. The mean flexion of the wrist on the affected side was 68° and 75° on the non-affected side. The average extension was 63° and 72°, respectively. The average grip strength was 35 kgf. This corresponds to 98% of the handgrip strength of the non-affected side, which was 37 kgf. The DASH score averaged 5 points. Conclusion: We believe that the use of bone graft obtained from the olecranon and secured with cannulated screw is a resolute technique for cases of linear nonunion of the Lichtmann type I scaphoid. It has the advantages of a new anesthesia for removal of the graft and the access is easy, providing a good exposure for removal and good aesthetic results. Level of evidence IV. Case series. PMID:27217819

  8. Arthroscopic grafting of scaphoid nonunion - surgical technique and preliminary findings from 23 cases.

    PubMed

    Cognet, J-M; Louis, P; Martinache, X; Schernberg, F

    2017-02-01

    We report our experience with the arthroscopic treatment of 23 cases of scaphoid nonunion. We explain the surgical technique and describe the different steps needed to achieve bone union. We report our initial clinical and radiological results. This was a prospective non-randomized study. Inclusion criteria were a scaphoid nonunion without radiocarpal arthritis, without any time limit and without any selection as to nonunion location. Before the operation, patients underwent an X-Ray and CT scan or MRI. Schernberg's classification was used to evaluate the location of the nonunion. Internal fixation was performed with a screw or K-wires. Bone grafts were taken from the dorsal side of the distal radius using a T-Lok™ bone marrow biopsy needle (Argon Medical Devices, Plano, TX, USA). A CT scan was performed 3 months after the operation to determine whether union was achieved. Pain, strength and range of motion were evaluated before and after the operation. The patients' smoking habits were also documented. The average follow-up was 17.3 months (4-41). There were 20 men and 3 women with an average age of 26 years (17-63). The average duration of nonunion before the operation was 17 months (6-60). Based on Schernberg's classification, there was one type I, 12 type II and 10 type III nonunions. Wrist strength increased from 32 to 41kg. Union was obtained in all patients after an average of 4 months (3-12). Numerous treatments have been described for treating scaphoid nonunion: Matti-Russe, Fisk-Fernadez bone graft, vascularized bone graft, bone substitutes, etc. The success rate varies depending on the technique and study design. We have described an arthroscopic technique for treating scaphoid nonunion with very promising preliminary results. Arthroscopic debridement is needed to ensure good quality bone at the graft site, while preserving extrinsic vascularization. Traction is used during the operation to restore the scaphoid height, once debridement has been

  9. Biomechanical Evaluation of Scaphoid and Lunate Kinematics Following Selective Sectioning of Portions of the Scapholunate Interosseous Ligament.

    PubMed

    Waters, Michael S; Werner, Frederick W; Haddad, Stefanos F; McGrattan, Michael L; Short, Walter H

    2016-02-01

    To determine the relative roles of the dorsal and volar portions of the scapholunate interosseous ligament (SLIL) in the stability of the scaphoid and lunate. Sixteen fresh cadaver wrists were moved through physiological motions using a wrist joint simulator. Electromagnetic sensors measured the motion of the scaphoid and lunate. Data were collected with the wrist intact, after randomly sectioning the dorsal SLIL first (8 wrists) or the volar SLIL first (8 wrists), and after full ligamentous sectioning. Differences in the percent increase in scaphoid flexion or lunate extension were compared using a t test with significance set at P < .05. Sectioning the dorsal SLIL accounted for 37%, 72%, and 68% of the increase in scaphoid flexion in wrist flexion-extension, radioulnar deviation, and dart throw motion as compared with complete SLIL sectioning. Sectioning the volar SLIL accounted for only 7%, 6%, and 14%, respectively. In the same 3 motions, sectioning the dorsal SLIL accounted for 55%, 57%, and 58% of the increase in lunate extension, whereas volar SLIL sectioning accounted for 27%, 28%, and 22%. The dorsal SLIL provides more stability to the scaphoid and lunate in biomechanical testing. The volar SLIL does provide some, although less, stability. Although this study supports the critical importance of dorsal SLIL repairs or reconstructions, it also shows that there may be some value in implementing a volar SLIL repair or reconstruction. Copyright © 2016 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  10. Manned Mars mission sunlight and communication occultations

    NASA Technical Reports Server (NTRS)

    Mulqueen, Jack

    1986-01-01

    Calculations are presented for the 1999 opposition class mission and a procedure for obtaining singlar occultation data for any other given Mars mission is given. Occultation data for a Mars orbiter in a 24.5 hour parking orbit and a Mars base were calculated for: sunlight occultation - the time in darkness; and radio communication occultation - the communication losses between the lander and the orbiter, the lander and Earth, and orbiter and Earth.

  11. Testing for Occult Heartworm Infection

    PubMed Central

    Stogdale, L.

    1984-01-01

    Heartworm infection in dogs is endemic in southern Ontario but occurs only sporadically throughout the remainder of Canada. The disease may either be associated with microfilariae in the patient's blood, a patent infection, or it may be occult. This paper describes a case of occult dirofilariasis in a dog, with emphasis on the diagnosis. A patent infection could be missed if the clinician tests an insufficient amount of blood. He should perform multiple concentration tests using either the modified Knott's technique or a filtration method. Occult infections occur in prepatent or unisexual infections, when the worms become sterile following therapy, or when the host produces antibodies that result in the destruction of the microfilariae. The recent release of a kit which detects the presence of antibodies to the adult heartworms now enables veterinarians to make an accurate diagnosis in the vast majority of dogs. PMID:17422386

  12. Solar Occultation Retrieval Algorithm Development

    NASA Technical Reports Server (NTRS)

    Lumpe, Jerry D.

    2004-01-01

    This effort addresses the comparison and validation of currently operational solar occultation retrieval algorithms, and the development of generalized algorithms for future application to multiple platforms. initial development of generalized forward model algorithms capable of simulating transmission data from of the POAM II/III and SAGE II/III instruments. Work in the 2" quarter will focus on: completion of forward model algorithms, including accurate spectral characteristics for all instruments, and comparison of simulated transmission data with actual level 1 instrument data for specific occultation events.

  13. Absent or occult pulmonary artery.

    PubMed Central

    Presbitero, P; Bull, C; Haworth, S G; de Leval, M R

    1984-01-01

    Of 12 patients with angiographically absent pulmonary artery, 11 were investigated surgically. The previously occult pulmonary artery was found in 10 patients, in five of whom a vestige of an intrapericardial artery was present and in five the artery was patent only at the hilus, a gap existing between the main pulmonary artery and the hilar vessel, and no artery was found in one. All patients with an intrapericardial artery had right ventricular outflow tract obstruction and a ductus descending vertically from underneath the aortic arch. In those without an intrapericardial vessel the occult artery was on the side opposite the aortic arch, and there was evidence of a ductus coming from the innominate artery on the side of the interruption. The occult pulmonary artery, where identified at operation, was usually joined initially to the systemic circulation. Ultimately, continuity between the hilar and main pulmonary artery may be established surgically. Where no intrapericardial vessel exists, however, a conduit may be required to bridge the gap. It seems advisable to search for the occult artery as early in life as is feasible in the hope that providing a blood supply will ensure development of the vessel and normal lung growth. Images PMID:6743435

  14. RSL Fusion with Excision of Distal Scaphoid and Triquetrum: A Cadaveric Study.

    PubMed

    Bain, Gregory Ian; Sood, Aman; Yeo, Chong Jin

    2014-02-01

    Radioscapholunate (RSL) fusion has been utilized for treatment of radiocarpal arthritis for patients with an intact midcarpal joint. This preserves midcarpal joint motion while alleviating pain. Dart thrower's motion (DTM), which has been emphasized recently, is mainly a midcarpal joint motion. Question A cadaveric study was designed to measure and compare the range of motion (ROM) of the human wrist before and after an RSL fusion, followed by distal scaphoid excision, and finally excision of the triquetrum. Methods Twelve embalmed adult cadaveric upper limbs were assessed. The wrist motion was measured with an electrogoniometer. Measurements of the flexion-extension plane and radial-ulnar deviation plane were obtained for baseline after capsulotomy, after simulated RSL fusion with memory staples, after distal scaphoidectomy, and after excision of the triquetrum. Results The effects of scaphoid and triquetrum excision were expressed as improvements in movement over that of the preceding step. RSL fusion alone resulted in a decrease of the flexion-extension (F-E) arc by 36% and the radioulnar deviation (R-U) arc by 30%. Excision of the distal scaphoid with RSL improved the F-E arc by 34% and the R-U arc by 34%. With excision of the triquetrum, the F-E arc improved further by 13% and the R-U arc by 21%. The ROM of the simulated RSL fusion with distal scaphoidectomy is improved with excising the triquetrum, mainly through an increase in ulnar deviation motion. RSL fusion with distal scaphoidectomy and triquetrectomy can be an alternative to total wrist arthrodesis for patients with an intact midcarpal joint.

  15. 21 CFR 864.6550 - Occult blood test.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Occult blood test. 864.6550 Section 864.6550 Food... DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6550 Occult blood test. (a) Identification. An occult blood test is a device used to detect occult blood in urine or feces. (Occult blood...

  16. 21 CFR 864.6550 - Occult blood test.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Occult blood test. 864.6550 Section 864.6550 Food... DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6550 Occult blood test. (a) Identification. An occult blood test is a device used to detect occult blood in urine or feces. (Occult blood...

  17. 21 CFR 864.6550 - Occult blood test.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Occult blood test. 864.6550 Section 864.6550 Food... DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6550 Occult blood test. (a) Identification. An occult blood test is a device used to detect occult blood in urine or feces. (Occult blood...

  18. 21 CFR 864.6550 - Occult blood test.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Occult blood test. 864.6550 Section 864.6550 Food... DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6550 Occult blood test. (a) Identification. An occult blood test is a device used to detect occult blood in urine or feces. (Occult blood...

  19. Radioimmune localization of occult carcinoma

    SciTech Connect

    Duda, R.B.; Zimmer, A.M.; Rosen, S.T.; Gilyon, K.A.; Webber, D.; Spies, S.; Spies, W.; Merchant, B. )

    1990-07-01

    Patients with a rising serum carcinoembryonic antigen level and no clinical or roentgenographic evidence of recurrent or metastatic cancer present a treatment dilemma. Eleven such patients, 10 with a previously treated colorectal carcinoma and 1 with a previously treated breast carcinoma, received an injection of the anticarcinoembryonic antigen monoclonal antibody ZCE-025 labeled with the radioisotope indium 111. Nuclear scintigraphy was performed on days 3 and 5 through 7 to detect potential sites of tumor recurrence. The monoclonal antibody scan accurately predicted the presence or absence of occult malignancy in 7 (64%) patients. Second-look laparotomy confirmed the monoclonal antibody scan results in the patients with colorectal cancer, and magnetic resonance imaging confirmed metastatic breast cancer. This study demonstrates that In-ZCE-025 can localize occult carcinoma and may assist the surgeon in facilitating the operative exploration. In-ZCE-025 assisted in the initiation of adjuvant therapy for the patient with breast cancer.

  20. IUVS/MAVEN Stellar Occultations

    NASA Astrophysics Data System (ADS)

    Gröller, Hannes; Yelle, Roger; Montmessin, Franck; Lacombe, Gaetan; Schneider, Nicholas M.; Deighan, Justin; Jain, Sonal; Nakagawa, Hiromu; Jakosky, Bruce

    2016-10-01

    We present the latest results from stellar occultations observed with the Imaging Ultraviolet Spectrograph (IUVS) instrument on board of Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. So far 9 campaigns have been executed on average every two months since MAVEN began orbiting Mars. Approximately 50 occultations are recorded in each campaign. The IUVS instrument observes in two spectral regions, the far- and mid-UV. The FUV channel covers wavelengths from 110 to 190 nm and the MUV channel from 170 to 350 nm. By combining those two channels we cover the whole altitude range starting from around 30 km to 150 km. We present the geometric dependent CO2, O2, and O3 number densities from these occultations. The derived O2 mixing ratio varies between 1.5 × 10-3 and 5 × 10-3. In some of the MUV occultations we also can see aerosol extinction. In addition we present temperatures derived from the CO2 densities assuming hydrostatic equilibrium. We retrieved mean temperatures of around 180 K at lower altitudes, which decreasing with altitudes down to a mean of around 130 K at higher altitudes. We see a constantly cold layer with temperatures of 105 - 120 K at a pressure level at roughly 7 × 10-6 Pa, equivalent to an altitude of around 140 km. We also discuss possible wave structures with amplitudes between 5 and 15 K and wavelengths between 10 and 15 km in the obtained temperature profiles. The temperature profiles, retrieved with the IUVS instrument, are mostly in agreement with predicted values from the Mars Climate Database model, except where we see the cold layer around 140 km.

  1. Triton stellar occultation candidates - 1992-1994

    NASA Technical Reports Server (NTRS)

    Mcdonald, S. W.; Elliot, J. T.

    1992-01-01

    A search for Triton stellar occultation candidates for the period 1992-1994 has been completed with CCD strip-scanning observations. The search reached an R magnitude of about 17.4 and found 129 candidates within 1.5 arcsec of Triton's ephemeris during this period. Of these events, around 30 occultations are expected to be visible from the earth, indicating that a number of Triton occultation events should be visible from major observatories. Even the faintest of the present candidate events could produce useful occultation data if observed with a large enough telescope. The present astrometric accuracy is inadequate to identify which of these appulse events will produce occultations on the earth; further astrometry is needed to refine the predictions for positive occultation identification. To aid in selecting candidates for additional astrometric and photometric studies, finder charts and earth-based visibility charts for each event are included.

  2. [The arthroscopic distal pole resection of the scaphoid: clinical results in STT osteoarthritis].

    PubMed

    Normand, J; Desmoineaux, P; Boisrenoult, P; Beaufils, P

    2012-02-01

    We present the results of surgical treatment of eight patients operated in the service of osteoarthritis scapho-trapézo-trapézoidienne (STT) by resection of the distal pole of the scaphoid under arthroscopic. Studies have already shown the good results of this technique in open surgery. This is a retrospective study of eight patients of mean age 70 years. They had an isolated STT osteoarthritis, which is not relieved by medical treatment. They were operated between 2004 and 2007 by the same surgeon and were reviewed at a mean of 13 months by an independent examiner. The evaluation was focused on pain, range of motion and grip strength. A radiological assessment was conducted to examine a possible carpal mal-alignment. Two patients were excluded because they had received a trapeziectomy for rhizarthrosis associated. The pain had decreased in seven cases with complete disappearance in six cases. The force had been increased or stabilized in seven cases and the mobility is the same in six cases. We got six very good results, one good result and one bad result without aggravation. Furthermore, no patient had been taken, nor any complications noted. The good results obtained with this minimally invasive outpatient surgery, encourages us to offer first-line therapy in patients with isolated STT osteoarthritis is not relieved by medical treatment. The resection of the distal pole of the scaphoide under arthoscopy gives less burdensome and less complication that the arthrodesis, while providing very good results. Copyright © 2012. Published by Elsevier SAS.

  3. Revisiting the 1988 Pluto Occultation

    NASA Astrophysics Data System (ADS)

    Bosh, Amanda S.; Dunham, Edward W.; Young, Leslie A.; Slivan, Steve; Barba née Cordella, Linda L.; Millis, Robert L.; Wasserman, Lawrence H.; Nye, Ralph

    2015-11-01

    In 1988, Pluto's atmosphere was surmised to exist because of the surface ices that had been detected through spectroscopy, but it had not yet been directly detected in a definitive manner. The key to making such a detection was the stellar occultation method, used so successfully for the discovery of the Uranian rings in 1977 (Elliot et al. 1989; Millis et al. 1993) and before that for studies of the atmospheres of other planets.On 9 June 1988, Pluto occulted a star, with its shadow falling over the South Pacific Ocean region. One team of observers recorded this event from the Kuiper Airborne Observatory, while other teams captured the event from various locations in Australia and New Zealand. Preceding this event, extensive astrometric observations of Pluto and the star were collected in order to refine the prediction.We will recount the investigations that led up to this important Pluto occultation, discuss the unexpected atmospheric results, and compare the 1988 event to the recent 2015 event whose shadow followed a similar track through New Zealand and Australia.

  4. Variation in Occult Injury Screening for Children With Suspected Abuse in Selected US Children’s Hospitals

    PubMed Central

    Feudtner, Chris; Medina, Sheyla P.; Luan, Xianqun; Localio, Russell; Rubin, David M.

    2012-01-01

    OBJECTIVE: To describe variation across selected US children’s hospitals in screening for occult fractures in children <2 years old diagnosed with physical abuse and in infants <1 year old who have injuries associated with a high likelihood of physical abuse. METHODS: We performed a retrospective study of children <2 years old with a diagnosis of physical abuse and infants <1 year old with non-motor vehicle crash–associated traumatic brain injuries or femur fractures admitted to 40 hospitals within the Pediatric Hospital Information System database from January 1, 1999, to December 31, 2009. We examined variation among the hospitals in the performance of screening for occult fractures as defined by receipt of skeletal survey or radionuclide bone scan. Marginal standardization implemented with logistic regression analysis was used to examine hospital variation after adjusting for patient demographic characteristics, injury severity, and year of admission. RESULTS: Screening for occult fractures was performed in 83% of the 10 170 children <2 years old with a diagnosis of physical abuse, 68% of the 9942 infants who had a traumatic brain injury, and 77% of the 2975 infants who had femur fractures. After adjustment for patient characteristics, injury severity, and year of admission, hospitals varied significantly in use of screening for occult fractures in all 3 groups of children. CONCLUSIONS: The observed variation in screening for occult fractures in young victims of physical abuse and infants who have injuries associated with a high likelihood of abuse underscores opportunities to improve the quality of care provided to this vulnerable population. PMID:23071208

  5. Scaling Relation for Occulter Manufacturing Errors

    NASA Technical Reports Server (NTRS)

    Sirbu, Dan; Shaklan, Stuart B.; Kasdin, N. Jeremy; Vanderbei, Robert J.

    2015-01-01

    An external occulter is a spacecraft own along the line-of-sight of a space telescope to suppress starlight and enable high-contrast direct imaging of exoplanets. The shape of an external occulter must be specially designed to optimally suppress starlight and deviations from the ideal shape due to manufacturing errors can result loss of suppression in the shadow. Due to the long separation distances and large dimensions involved for a space occulter, laboratory testing is conducted with scaled versions of occulters etched on silicon wafers. Using numerical simulations for a flight Fresnel occulter design, we show how the suppression performance of an occulter mask scales with the available propagation distance for expected random manufacturing defects along the edge of the occulter petal. We derive an analytical model for predicting performance due to such manufacturing defects across the petal edges of an occulter mask and compare this with the numerical simulations. We discuss the scaling of an extended occulter test-bed.

  6. Finite element modeling of the influence of hand position and bone properties on the Colles' fracture load during a fall.

    PubMed

    Buchanan, Drew; Ural, Ani

    2010-08-01

    Distal forearm fracture is one of the most frequently observed osteoporotic fractures, which may occur as a result of low energy falls such as falls from a standing height and may be linked to the osteoporotic nature of the bone, especially in the elderly. In order to prevent the occurrence of radius fractures and their adverse outcomes, understanding the effect of both extrinsic and intrinsic contributors to fracture risk is essential. In this study, a nonlinear fracture mechanics-based finite element model is applied to human radius to assess the influence of extrinsic factors (load orientation and load distribution between scaphoid and lunate) and intrinsic bone properties (age-related changes in fracture properties and bone geometry) on the Colles' fracture load. Seven three-dimensional finite element models of radius were created, and the fracture loads were determined by using cohesive finite element modeling, which explicitly represented the crack and the fracture process zone behavior. The simulation results showed that the load direction with respect to the longitudinal and dorsal axes of the radius influenced the fracture load. The fracture load increased with larger angles between the resultant load and the dorsal axis, and with smaller angles between the resultant load and longitudinal axis. The fracture load also varied as a function of the load ratio between the lunate and scaphoid, however, not as drastically as with the load orientation. The fracture load decreased as the load ratio (lunate/scaphoid) increased. Multiple regression analysis showed that the bone geometry and the load orientation are the most important variables that contribute to the prediction of the fracture load. The findings in this study establish a robust computational fracture risk assessment method that combines the effects of intrinsic properties of bone with extrinsic factors associated with a fall, and may be elemental in the identification of high fracture risk individuals

  7. Evaluation of Associated Carpal Bone Fractures in Distal Radial Fractures

    PubMed Central

    Heo, Youn Moo; Kim, Sang Bum; Yi, Jin Woong; Park, Cheol Yong; Yoon, Jeong Yong; Kim, Doo Hyun

    2013-01-01

    Background The purpose of this study was to investigate the frequency and distribution of associated carpal bone fractures (CBFs) in distal radial fractures (DRFs). Methods Three hundred and thirteen patients who underwent surgical treatment for DRFs between March 2007 and January 2010 were reviewed retrospectively. In this study, 223 patients who had preoperative computed tomography (CT) were included. We investigated the frequency and distribution of associated CBFs on CT scans. The relationship between the frequency of associated CBFs and patient factors such as age, gender, body mass index, and the mechanism of injury was assessed. Results CBFs were complicated in 46 of 223 DRFs (20.9%). The distribution of CBFs was 23 cases in the triquetrum, 16 in the lunate, 12 in the scaphoid, five in the hamate, and four in the pisiform. Among the 46 cases, a fracture of one carpal bone occurred in 36 cases, two in seven cases, three in two cases, and four in one case. In 10 of the 46 cases, associated CBFs occurred in more than two carpal bones. No significant differences were observed for age, sex, body mass index, or the mechanism of injury between patients with DRFs and CBFs and those without CBFs. Conclusions Because CBFs that mainly occur in the proximal carpal row are complicated in DRFs at a relatively high frequency, assessment of carpal bones using CT scans is beneficial. PMID:23730472

  8. Illinois occultation summary. II - 1979

    NASA Technical Reports Server (NTRS)

    Radick, R.; Lien, D.

    1982-01-01

    Lunar occultation records are presented for the third year of a continuing program. Included are 17 observations of stars brighter than seventh magnitude, 13 reappearances, four angular diameter measurements, and seven observations of stars that are either binary or may be double. The observations were made with Stromgren y filter, the u or b filter, or the FI filter described in the first paper of this series (Radick and Lien, 1980). Five observations, including four of Aldebaran, were made with two filters centered on or near H-alpha.

  9. [The scaphoid and rheumatoid arthritis : Classification by retrospective X‑ray analysis].

    PubMed

    Lautenbach, M; Zach, A; Eisenschenk, A

    2016-11-01

    Early destruction of the wrist in rheumatoid arthritis is common and often progressive. Even in times of improved and standardized medical treatment this cannot always be prevented. A limited range of motion, pain, reduced grip-force, and aesthetic deficits of the wrist can impair the daily life of patients. There is an additional risk for destruction of the surrounding soft tissue and adjoining joints of the upper extremity. Destruction of wrist in rheumatoid arthritis is multifactorial and is localized in many different structures of the wrist. In this context, scaphoid and periscaphoid structures are of interest. Data were gathered in a retrospective study of the wrist X‑rays of patients with rheumatoid arthritis. The possible consequences for operative options are described.

  10. Occult Carcinoma of the Bronchus

    PubMed Central

    Pearson, F. G.; Thompson, D. W.

    1966-01-01

    The term “occult carcinoma” is applied to those patients with carcinoma of the bronchus at an in situ or early invasive stage who have carcinoma cells in their sputum but have no recognizable evidence of tumour in the chest radiograph. In eight such patients at the Toronto General Hospital, the lesion was localized and treatment instituted. Our experience with these eight patients can be compared with that of 27 patients described in two similar studies. The lesions were commonly symptomatic. Localization, although sometimes difficult, was accomplished using information obtained during bronchoscopy and bronchography. The prognosis following adequate resection appeared excellent. No patient died of carcinoma during the post-treatment follow-up period, which was continued for a minimum of 18 months. Pathological evidence indicates that bronchial carcinoma at this occult stage can be diagnosed cytologically, is rarely multifocal and, as a localized neoplasm, is amenable to curative therapy. ImagesFig. 1Fig. 2Fig. 3Fig. 4Fig. 5Fig. 6Fig. 7Fig. 8Fig. 9Fig. 10Fig. 11Fig. 12Fig. 13 PMID:5929532

  11. Synovitis of the wrist joint caused by an intraarticular perforation of an osteoid osteoma of the scaphoid

    PubMed Central

    Bhardwaj, Praveen; Sharma, Chetna; Sabapathy, S Raja

    2012-01-01

    Uncommon location and atypical presentation of the osteoid osteomas of the scaphoid can pose a diagnostic challenge. Because of its intraarticular location, scaphoid osteoid osteoma can present with synovitis which is the more commonly reported presentation for other intraarticular locations like in hip and elbow and only rarely reported at the wrist. We report a case of perforation of the osteoid osteoma into the wrist joint, resulting in exuberant synovitis. The clinical significance of this report is to reinforce that synovitis can be a presentation of osteoid osteoma and it should be considered in the differential diagnosis of monoarticular arthritis. Prolonged synovitis may cause damage to the other joint surfaces of the wrist and hence carpal osteoid osteoma should be considered for early surgical excision. PMID:23162159

  12. Occult maxillofacial trauma in epilepsy.

    PubMed

    Aragon, C E; Burneo, J G; Helman, J

    2001-11-15

    Epilepsy is a relatively common neurological disorder with incidence in both developed and developing countries. Head, facial, and oral injuries can result from seizures experienced by the epileptic patient. Patients with severe epilepsy often experience other dental disease due to their inability to properly maintain their oral hygiene. This paper presents a case of a chronic mandibular fracture following an episode of seizures in a patient with epilepsy in whom the fracture was discovered when he developed a fistula in the submandibular region.

  13. Future Nanosatellite Constellation for Radio Occultation Measurements

    NASA Astrophysics Data System (ADS)

    Fallet, C.; Mahfouf, J. F.; Hauchechrne, A.; Mathieu, R.; Martin, T.; Capet, N.; Mandea, M.

    2016-08-01

    The future nanosatellite constellation for radio occultation measurements aims to provide 10000 occultations per day (horizon 2020). The radio occultation technique based on the refraction of an electromagnetic signal between a GNSS satellite (Global Navigation Satellite System) and a receiver satellite located o a low orbit provides a way to observe the Earth's atmosphere, especially its temperature, pressure and water vapor, but also the ionosphere. This technique is now considered a mature concept, the benefits clearly recognized by the communities of weather prediction, climatology and space weather. Activities are underway at CNES to define a low cost system and instrumental concept to satisfy the specifications of the different communities.

  14. The Lunar Occultation Observer (LOCO) mission concept

    NASA Astrophysics Data System (ADS)

    Miller, Richard S.

    2007-09-01

    The hard X-ray sky has tremendous potential for future discoveries and is one of the last electromagnetic regimes without a sensitive all-sky survey. A new approach to such a survey is to utilize the Moon as an occulting disk. The Lunar Occultation Observer (LOCO) mission concept, based on this Lunar Occultation Technique (LOT) and incorporating advanced inorganic scintillators as a detection medium, represents a sensitive and cost effective option for NASA's Beyond Einstein Black Hole Finder Probe or a future Explorer-class mission. We present the motivating factors for the LOT, outline developmental details and simulation results, as well as give preliminary estimates for source detection sensitivity.

  15. Stellar Occultation Studies of the Solar System

    NASA Astrophysics Data System (ADS)

    Elliot, James L.

    1998-01-01

    Earth-based observations of stellar occultations provide extremely high spatial resolution for bodies in the outer solar system, about 10,000 times better than that of traditional imaging observations. Stellar occultation data can be used to establish the structure of atmospheres and rings of solar system bodies at high spatial resolution. Airborne occultation observations are particularly effective, since the controlled mobility of the observing platform allows the observer to fly within the optimum part of the occultation shadow for most events that are visible from Earth. Airborne observations are carried out above any clouds and are nearly free of scintillation noise from the Earth's atmosphere. KAO occultation observations resulted in the first detection of gravity waves in the Martian atmosphere, discovery of the Uranian rings, the first detection of Pluto's atmosphere, the first Earth-based investigations of Triton's atmosphere, and the discovery of narrow jets from Chiron's nucleus. The first SOFIA occultation opportunity will be an investigation of Pluto's atmospheric structure in November, 2002, and will resolve a problem that has lingered since the KAO discovery observation fourteen years earlier. We plan to continue our successful airborne occultation program with the greatly enhanced capability provided by SOFIA. We propose here to replace our KAO occultation photometer with one having twice the throughput, half the noise, a somewhat wider wavelength range, four times the field of view, and ten times the frame rate to optimize its performance and to capitalize on the larger collecting area offered by SOFIA. It will also allow for simultaneous visible and IR occultation observations, greatly enriching the results that we can obtain from occultations. We call this new imaging occultation photometer HOPI (High-speed Occultation Photometer and Imager). HOPI will provide a signal-to-noise ratio two to four times that of our present photometer for a given

  16. Stellar Occultation Studies of the Solar System

    NASA Technical Reports Server (NTRS)

    Elliot, James L.

    1998-01-01

    Earth-based observations of stellar occultations provide extremely high spatial resolution for bodies in the outer solar system, about 10,000 times better than that of traditional imaging observations. Stellar occultation data can be used to establish the structure of atmospheres and rings of solar system bodies at high spatial resolution. Airborne occultation observations are particularly effective, since the controlled mobility of the observing platform allows the observer to fly within the optimum part of the occultation shadow for most events that are visible from Earth. Airborne observations are carried out above any clouds and are nearly free of scintillation noise from the Earth's atmosphere. KAO occultation observations resulted in the first detection of gravity waves in the Martian atmosphere, discovery of the Uranian rings, the first detection of Pluto's atmosphere, the first Earth-based investigations of Triton's atmosphere, and the discovery of narrow jets from Chiron's nucleus. The first SOFIA occultation opportunity will be an investigation of Pluto's atmospheric structure in November, 2002, and will resolve a problem that has lingered since the KAO discovery observation fourteen years earlier. We plan to continue our successful airborne occultation program with the greatly enhanced capability provided by SOFIA. We propose here to replace our KAO occultation photometer with one having twice the throughput, half the noise, a somewhat wider wavelength range, four times the field of view, and ten times the frame rate to optimize its performance and to capitalize on the larger collecting area offered by SOFIA. It will also allow for simultaneous visible and IR occultation observations, greatly enriching the results that we can obtain from occultations. We call this new imaging occultation photometer HOPI (High-speed Occultation Photometer and Imager). HOPI will provide a signal-to-noise ratio two to four times that of our present photometer for a given

  17. Reflective Occultation Mask for Evaluation of Occulter Designs for Planet Finding

    NASA Technical Reports Server (NTRS)

    Hagopian, John; Lyon, Richard; Shiri, Shahram; Roman, Patrick

    2011-01-01

    Advanced formation flying occulter designs utilize a large occulter mask flying in formation with an imaging telescope to block and null starlight to allow imaging of faint planets in exosolar systems. A paper describes the utilization of subscale reflective occultation masks to evaluate formation flying occulter designs. The use of a reflective mask allows mounting of the occulter by conventional means and simplifies the test configuration. The innovation alters the test set-up to allow mounting of the mask using standard techniques to eliminate the problems associated with a standard configuration. The modified configuration uses a reflective set-up whereby the star simulator reflects off of a reflective occulting mask and into an evaluation telescope. Since the mask is sized to capture all rays required for the imaging test, it can be mounted directly to a supporting fixture without interfering with the beam. Functionally, the reflective occultation mask reflects light from the star simulator instead of transmitting it, with a highly absorptive carbon nanotube layer simulating the occulter blocking mask. A subscale telescope images the star source and companion dim source that represents a planet. The primary advantage of this is that the occulter can be mounted conventionally instead of using diffractive wires or magnetic levitation.

  18. Scaling Relation for Occulter Manufacturing Errors

    NASA Technical Reports Server (NTRS)

    Sirbu, Dan; Shaklan, Stuart B.; Kasdin, N. Jeremy; Vanderbei, Robert J.

    2015-01-01

    For directly imaging exoplanets, NASA is considering space mission designs that use an external occulter as the principal starlight suppression system. These occulter designs range in diameter from 16 to 40 meters and separation distance from 8,000 to 60,000 kilometers for telescopes with primary diameters of 0.5 to 4 meters. Occulter shapes are solutions to an optimization problem which seeks to maximize suppression in the shadow subject to constraints such as size, separation, and wavelengths. These designs are based on scalar diffraction theory and must be verified experimentally to demonstrate predicted on-orbit performance. Due to the large sizes and separations involved the experiment must be scaled to lab size. We are currently expanding the existing experimental test-bed at Princeton to enable scaling of occulters operating at flight Fresnel sizes. Here we examine the effect on suppression performance of edge defects and their scaling to test-bed size.

  19. PICO: Portable Instrument for Capturing Occultations

    NASA Astrophysics Data System (ADS)

    Lockhart, Matthew; Person, Michael J.; Elliot, J. L.; Souza, Steven P.

    2010-10-01

    We describe a portable imaging photometer for the observation of stellar occultation events by Kuiper Belt objects (KBOs) and other small bodies. The system is referred to as the Portable Instrument for Capturing Occultations (PICO). It is designed to be transportable to remote observing sites by a single observer. A GPS timing system is used to trigger exposures of a Finger Lakes Instrumentation ML261E-25 camera to facilitate the combination of observational results from multiple sites. The system weighs a total of 11 kg when packed into its single rigid 55.1 × 35.8 × 22.6 cm container, meeting current airline size and weight limits for carry-on baggage. Twelve such systems have been constructed. Nine systems were deployed for observation of a stellar occultation by Kuiper Belt object 55636 in 2009 October. During the same month, one system was used to record a stellar occultation by minor planet 762 Pulcova.

  20. Study of the technique of stellar occultation

    NASA Technical Reports Server (NTRS)

    Hays, P. B.; Graves, M. E.; Roble, R. G.; Shah, A. N.

    1973-01-01

    The results are reported of a study of the stellar occultation technique for measuring the composition of the atmosphere. The intensity of starlight was monitored during the occultation using the Wisconsin stellar ultraviolet photometers aboard the Orbiting Astronomical Observatory (OAO-A2). A schematic diagram of an occultation is shown where the change in intensity at a given wavelength is illustrated. The vertical projection of the attenuation region is typically 60 km deep for molecular oxygen and 30 km deep for ozone. Intensity profiles obtained during various occultations were analyzed by first determining the tangential columm density of the absorbing gases, and then Abel inverting the column densities to obtain the number density profile. Errors are associated with each step in the inversion scheme and have been considered as an integral part of this study.

  1. McDonald's and the Occult.

    ERIC Educational Resources Information Center

    Singer, Barry

    1979-01-01

    Discusses "occult" and "paranormal" literature which is often mistaken for nonfiction. Suggests that most publishers are unwilling to publish scientific perspectives on the paranormal because such writings would be unmarketable. Journal availability: see SO 507 190. (KC)

  2. Triton stellar occultation candidates: 1995-1999

    NASA Technical Reports Server (NTRS)

    Mcdonald, S. W.; Elliot, J. L.

    1995-01-01

    We have completed a search for candidates for stellar occultations by Triton over the years 1995-1999. CCd strip scan images provided star positions in the relevant sky area to a depth of about 17.5 R magnitude. Over this time period, we find that Triton passes within 1.0 arcsec of 75 stars. Appulses with geocentric minimum separations of less than 0.35 arcsec will result in stellar occultations, but further astrometry and photometry is necessary to refine individual predictions for identification of actual occultations. Finder charts are included to aid in further studies and prediction refinement. The two most promising potential occultations, Tr176 and Tr180, occur in 1997.

  3. McDonald's and the Occult.

    ERIC Educational Resources Information Center

    Singer, Barry

    1979-01-01

    Discusses "occult" and "paranormal" literature which is often mistaken for nonfiction. Suggests that most publishers are unwilling to publish scientific perspectives on the paranormal because such writings would be unmarketable. Journal availability: see SO 507 190. (KC)

  4. Cassini SOI Radio Occultation of Saturn's Rings

    NASA Astrophysics Data System (ADS)

    Marouf, E.; French, R.; Rappaport, N.; Thomson, F.; McGhee, C.; Asmar, S.; Johnston, D.

    2004-11-01

    On July 1, 2005 at 01:12 SCET-UTC, Cassini started the engine burn required to insert the spacecraft into orbit around Saturn (SOI). Almost 30 minutes later, Cassini was occulted by Saturn's rings as seen from the Earth. The geometric ring occultation covered all main ring features, starting at the outer edge of Ring A at 01:42 and ending at the inner edge of Ring C at 02:40. From 01:12 to 03:07, Cassini X-band radio signal (3.6 cm-wavelength) was turned on, primarily to monitor the burn. The sinusoidal transmitted signal was referenced to the on board ultrastable oscillator, allowing measurement of the signal amplitude and phase at the 70-m ground receiving station of the Deep Space Network at Canberra, Australia. As a useful by-product, a complete ring occultation observation, including free-space baseline, was achieved. Because of the special orientation of the spacecraft during the burn, the Cassini low-gain antenna was used to transmit the signal. Nominal radio occultations are conducted using the high-gain antenna, hence have intrinsic free-space signal-to-noise ratio (SNR) higher by a factor of 10,000 than the SOI occultation. Nonetheless, clearly detectable signal was observed during occultation by features in Rings A, Cassini Division, and Ring C, but not Ring B. The measurements, after reconstruction to remove diffraction effects, may be used to obtain an optical-depth and phase-shift profiles of resolved ring features. Achievable radial resolution primarily depends on the ring-opening-angle B, available free-space SNR, and occultation geometry. We compare radial resolution achievable for the Cassini SOI occultation (B = 24.7 deg, SNR = 10 dB-Hz) with those of the Voyager ring occultation (B = 5.9 deg, SNR = 50 dB-Hz), and contrast the results with those expected from nominal radio occultations during the Cassini tour. Example optical depth profiles from the Cassini SOI occultation are presented.

  5. Radio occultation measurements of the lunar ionosphere.

    NASA Astrophysics Data System (ADS)

    Pluchino, S.; Schillirò, F.; Salerno, E.; Pupillo, G.; Maccaferri, G.; Cassaro, P.

    Radio occultation measurements by using interplanetary probes is a well known technique to obtain information on planetary atmospheres. To further understand the morphology of the lunar ionosphere we performed radio occultation experiments by using the radio sounding technique. This method mainly consists in the analisys of the effects produced on the radio wave transmitted from the spacecraft to the Earth when it crosses the atmosphere. The wave amplitude and phase undergo modifications that are correlated to the physical parameters - i.e. electron density - of the crossed medium. The first data set was obtained during the lunar occultations of the European probe SMART-1 shortly before impacting the lunar soil on September 3rd, 2006. During this experiment several radio occultation measurements of the signal transmitted by the spacecraft were performed in S and X band by using the 32 meters radiotelescopes (at Medicina and Noto) of the Istituto di Radioastronomia - Istituto Nazionale di Astrofisica. Further experiments were performed during lunar occultations of Saturn and Venus. On May 22nd and June 18th 2007 the Cassini spacecraft, orbiting Saturn, and the Venus Express spacecraft, orbiting Venus, respectively were occulted by the Moon. The variation of the Total Electron Content (TEC) measured by our instruments (˜ 1013 el/m2) on this occasion is in agreement with values of the electron number density acquired by in situ measuments of the US Apollo missions and the USSR Luna 19 and 22 probes.

  6. Method of Modeling and Simulation of Shaped External Occulters

    NASA Technical Reports Server (NTRS)

    Lyon, Richard G. (Inventor); Clampin, Mark (Inventor); Petrone, Peter, III (Inventor)

    2016-01-01

    The present invention relates to modeling an external occulter including: providing at least one processor executing program code to implement a simulation system, the program code including: providing an external occulter having a plurality of petals, the occulter being coupled to a telescope; and propagating light from the occulter to a telescope aperture of the telescope by scalar Fresnel propagation, by: obtaining an incident field strength at a predetermined wavelength at an occulter surface; obtaining a field propagation from the occulter to the telescope aperture using a Fresnel integral; modeling a celestial object at differing field angles by shifting a location of a shadow cast by the occulter on the telescope aperture; calculating an intensity of the occulter shadow on the telescope aperture; and applying a telescope aperture mask to a field of the occulter shadow, and propagating the light to a focal plane of the telescope via FFT techniques.

  7. Skull fracture

    MedlinePlus

    ... may have been drinking alcohol or is otherwise impaired. Alternative Names Basilar skull fracture; Depressed skull fracture; Linear skull fracture Images Skull of an adult Skull fracture Skull fracture ...

  8. Pollen and water limitation in Astragalus scaphoides, a plant that flowers in alternate years.

    PubMed

    Crone, Elizabeth E; Lesica, Peter

    2006-11-01

    Mast seeding is common in plant populations, but its causes have rarely been tested experimentally. We tested mechanisms of alternate-year flowering and fruit set in an iteroparous, bee-pollinated, herbaceous plant, Astragalus scaphoides, in semi-arid sagebrush steppe. Patterns of reproduction from 1986 to 1999 indicated that spring precipitation was a cue for synchronous flowering, and that increased pollination in high-flowering years was a fitness advantage of synchrony. We tested these patterns by adding supplemental water and pollen to plants in high- and low-flowering sites and years. Supplemental water had no effect on flowering or seed set, so water is not a proximate cue for reproduction, though it could be important over longer (>3 year) time scales. Supplemental pollination increased fruit set in low- but not high-flowering years, indicating that synchronous flowering increases pollination success. Many shorter-term studies also report increased fruit set after pollen supplementation, but not after resource addition. This pattern may reflect the fact that plants can store and reallocate resources, but not pollen, across multiple years. For animal-pollinated herbs such as these, uniting theories about pollination ecology and mast seeding may promote an understanding of the mechanisms that determine patterns of reproduction over time.

  9. [The scaphoid-trapezium-trapezoid arthrosis. A clinical study 1982-1985].

    PubMed

    Wilhelm, K; Rolle, A; Hild, A

    1989-02-01

    The present study deals with patients in whom the diagnostic procedures applied in rhizoid arthrosis were considered to reveal scaphoid-trapezium-trapezoid (STT) arthrosis. Between 1982 and 1985, 21 of 396 rhizoid arthrosis patients developed symptoms of STT arthosis. Examination of the case histories showed that in 20 STT patients the pathogenesis included trauma. In addition, the majority of these 396 patients (71.5%) had to be retreated because of new traumata and the resultant problems. The time lapse between the first trauma considered sufficiently severe to have caused STT arthrosis and its diagnosis was up to 7.1 years. Our improved facilities for diagnosis of pathologic conditions of the wrist enabled us to distinguish four types of STT arthrosis. Persistent complex instability of the capsular ligament appears to be the major cause of post-traumatic STT arthrosis. Extended diagnostic techniques based on standardized radiograms allow the development of a design for treatment aimed at preventing posttraumatic STT of the hand as far as possible.

  10. Earth rotation derived from occultation records

    NASA Astrophysics Data System (ADS)

    Sôma, Mitsuru; Tanikawa, Kiyotaka

    2016-04-01

    We determined the values of the Earth's rotation parameter, ΔT = T T - UT, around AD 500 after confirming that the value of the tidal acceleration, dot{n}, of the lunar motion remained unchanged during the period between ancient times and the present. For determining of ΔT, we used contemporaneous occultations of planets by the Moon. In general, occultation records are not useful. However, there are some records that give us a stringent condition for the range of ΔT. Records of the lunar occultations in AD 503 and AD 513 are such examples. In order to assure the usefulness of this occultation data, we used contemporaneous annular and total solar eclipses, which have not been used in the preceding work. This is the first work in which the lunar occultation data have been used as primary data to determine the value of ΔT together with auxiliary contemporaneous annular and total solar eclipses. Our ΔT value is less than a smoothed value (Stephenson 1997) by at least 450 s. The result is consistent with our earlier results obtained from solar eclipses.

  11. Current management of occult bacteremia in infants.

    PubMed

    Mekitarian Filho, Eduardo; Carvalho, Werther Brunow de

    2015-01-01

    To summarize the main clinical entities associated with fever without source (FWS) in infants, as well as the clinical management of children with occult bacteremia, emphasizing laboratory tests and empirical antibiotics. A non-systematic review was conducted in the following databases--PubMed, EMBASE, and SciELO, between 2006 and 2015. The prevalence of occult bacteremia has been decreasing dramatically in the past few years, due to conjugated vaccination against Streptococcus pneumoniae and Neisseria meningitidis. Additionally, fewer requests for complete blood count and blood cultures have been made for children older than 3 months presenting with FWS. Urinary tract infection is the most prevalent bacterial infection in children with FWS. Some known algorithms, such as Boston and Rochester, can guide the initial risk stratification for occult bacteremia in febrile infants younger than 3 months. There is no single algorithm to estimate the risk of occult bacteremia in febrile infants, but pediatricians should strongly consider outpatient management in fully vaccinated infants older than 3 months with FWS and good general status. Updated data about the incidence of occult bacteremia in this environment after conjugated vaccination are needed. Copyright © 2015 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  12. First Stellar Occultation Observation with SOFIA

    NASA Astrophysics Data System (ADS)

    Dunham, Edward W.; Bida, T.; Bosh, A.; Collins, P.; Levine, S.; Person, M.; Pfueller, E.; Roeser, H.; Taylor, B.; Wiedemann, M.; Wolf, J.; Zuluaga, C.

    2012-01-01

    We successfully observed the 2011 June 23 UT stellar occultation by Pluto with the High-speed Imaging Photometer for Occultations (HIPO) instrument from Lowell Observatory and the Fast Diagnostic Camera (FDC) from the Deutches SOFIA Institut (DSI) mounted on the SOFIA telescope. A major prediction astrometry effort focused at MIT combined with the willingness of the SOFIA project to entertain the idea of an in-flight change to the flight plan allowed us to target the center of the occultation shadow. This was accomplished by means of an in-flight prediction update by satellite telephone and a real-time onboard flight plan modification to accommodate the prediction update. We obtained excellent results with both channels of HIPO and the FDC with each light curve showing a small, extended brightening while the star was occulted. We will discuss analysis results as well as SOFIA's considerable potential for future occultation work. We thank the SOFIA program for its willingness to attempt this challenging observation at such an early stage of SOFIA science operations. Lowell's SOFIA work was supported by a grant from USRA, MIT's prediction work was supported by the NASA Planetary Astronomy Program and the National Science Foundation, and the FDC work was supported by the DSI. We thank the US Naval Observatory Flagstaff Station for allowing us to use their facilities to obtain our prediction astrometry observations.

  13. Oligometastasis as a predictor for occult disease.

    PubMed

    Kendal, Wayne S

    2014-05-01

    Oligometastasis can be defined as a state of limited metastases that is potentially amenable to ablative local therapy; the success of such therapy depends on whether or not additional occult metastases exist. A model is presented here to predict occult metastases given detectable oligometastases. Predictions were based on Bayes' theorem, in conjunction with descriptions of the statistical distributions for the sizes and numbers of hematogenous metastases. The background probability for occult metastases in individuals with oligometastases increased markedly with relatively minor increases in metastatic potential. With each additional metastasis detected the chance of further occult metastases increased. These latter increases were incremental and proportionately smaller with the more metastatic tumors. Long disease free intervals had a major effect to decrease in the probability of further occult disease. Demonstration of oligometastases depends heavily upon the sensitivity of radiological imaging techniques, where the proportion of detectable metastases relates to the position of the distribution of metastasis growth times with respect to the detection threshold. Given the limitations of radiological methods, and the possibility that the oligometastases detected may be the only disease, an aggressive approach appears indicated.

  14. The Big Occulting Steerable Satellite (BOSS)

    SciTech Connect

    Copi, Craig J.; Starkman, Glenn D.

    2000-03-20

    Natural (such as lunar) occultations have long been used to study sources on small angular scales, while coronographs have been used to study high-contrast sources. We describe here the properties of the Big Occulting Steerable Satellite (BOSS), a large steerable occulting satellite to combine both of these techniques. BOSS will have several advantages over standard occulting bodies. BOSS would block all but about 4x10{sup -5} of the light at 1 {mu}m in the region of interest around the star for planet detections (with even better blocking possible using new film surface etching techniques). Because the occultation occurs outside the telescope, scattering inside the telescope does not degrade this performance. BOSS could be combined with a space telescope at the Earth-Sun L2 point to yield very long integration times, in excess of 3000 s. If placed in Earth orbit, integration times of 160-1600 s can be achieved from most major telescope sites for objects in over 90% of the sky. Applications for BOSS include direct imaging of planets around nearby stars. Planets separated by as little as 0.1''-0.25'' from the star they orbit could be seen down to a relative intensity as little as 1x10{sup -9} around a magnitude 8 (or brighter) star. Other applications include ultra-high-resolution imaging of compound sources, such as microlensed stars and quasars, down to a resolution as little as 0.1 mas. (c) 2000 The American Astronomical Society.

  15. [Progress in research of occult hepatitis B virus infection].

    PubMed

    Huang, X Y; Shi, Q F; Huang, T

    2017-05-10

    Occult hepatitis B virus infection is a worldwide public health problem, which seriously affects the clinical diagnosis of hepatitis B and threatens the safety of blood transfusion. The concept of occult hepatitis B virus infection, the pathogenesis of occult hepatitis B virus infection, the prevalence of occult hepatitis B virus infection in different groups, including healthy population and different patients, and the possibility of transmission were summarized. The prevalence of occult hepatitis B virus infection was found in healthy population and different patients, and there is possibility of occult hepatitis B virus infection to be transmitted through blood transfusion. The paper provides a comprehensive introduction of the pathogenesis and prevalence of occult hepatitis B virus infection. More attention should be paid to occult hepatitis B virus infection.

  16. Occult hepatitis B virus infection

    PubMed Central

    Kwak, Min-Sun; Kim, Yoon Jun

    2014-01-01

    Occult hepatitis B virus (HBV) infection (OBI) refers to the presence of HBV DNA in the absence of detectable hepatitis B surface antigen. Since OBI was first described in the late 1970s, there has been increasing interest in this topic. The prevalence of OBI varies according to the different endemicity of HBV infection, cohort characteristics, and sensitivity and specificity of the methods used for detection. Although the exact mechanism of OBI has not been proved, intra-hepatic persistence of viral covalently closed circular DNA under the host’s strong immune suppression of HBV replication and gene expression seems to be a cause. OBI has important clinical significance in several conditions. First, OBI can be transmitted through transfusion, organ transplantation including orthotopic liver transplantation, or hemodialysis. Donor screening before blood transfusion, prophylaxis for high-risk organ transplantation recipients, and dialysis-specific infection-control programs should be considered to reduce the risk of transmission. Second, OBI may reactivate and cause acute hepatitis in immunocompromised patients or those receiving chemotherapy. Close HBV DNA monitoring and timely antiviral treatment can prevent HBV reactivation and consequent clinical deterioration. Third, OBI may contribute to the progression of hepatic fibrosis in patients with chronic liver disease including hepatitis C. Finally, OBI seems to be a risk factor for hepatocellular carcinoma by its direct proto-oncogenic effect and by indirectly causing persistent hepatic inflammation and fibrosis. However, this needs further investigation. We review published reports in the literature to gain an overview of the status of OBI and emphasize the clinical importance of OBI. PMID:25544873

  17. Image Analysis of the 2012 Pluto (Near) Occultation

    DTIC Science & Technology

    2013-09-01

    5 Hz for 40 minutes before and after the expected time of occultation. The initial analysis of the photometry indicated that Pluto did not occult...that we would see it. The photometry said that we did not. From our viewpoint, the data had value in addition to the possibility of investigating...minutes before and after the expected time of occultation. The initial analysis of the photometry indicated that Pluto did not occult the star. This

  18. Chiron stellar occultation candidates: 1993-1996

    NASA Technical Reports Server (NTRS)

    Bus, S. J.; Wasserman, L. H.; Elliot, J. L.

    1994-01-01

    A photographic search was conducted for stars that may be occulted by the unusual solar system object (2060) Chiron during the period from fall 1993 through summer 1996. 44 candidates were identified to a limiting V magnitude of 16, and for which the minimum appulse separation with Chiron is predicted to be less than 2.5 arcsec. The successful observation of a stellar occultation by Chiron would give a direct measure of its diameter (currently estimated to be between 60 and 300 km), and would help considerably in constraining Chiron's surface properties and volatile makeup. If at the time of the occultation, Chiron exhibits a significant coma, there is also the potential for measuring the optical-depth profile of the dust in its inner coma.

  19. Occult primary, version 3.2014.

    PubMed

    Ettinger, David S; Handorf, Charles R; Agulnik, Mark; Bowles, Daniel W; Cates, Justin M; Cristea, Mihaela; Dotan, Efrat; Eaton, Keith D; Fidias, Panagiotis M; Gierada, David; Gilcrease, G Weldon; Godby, Kelly; Iyer, Renuka; Lenzi, Renato; Phay, John; Rashid, Asif; Saltz, Leonard; Schwab, Richard B; Shulman, Lawrence N; Smerage, Jeffrey B; Stevenson, Marvaretta M; Varadhachary, Gauri R; Zager, Jonathan S; Zhen, Weining Ken; Bergman, Mary Anne; Freedman-Cass, Deborah A

    2014-07-01

    The NCCN Guidelines for Occult Primary tumors provide recommendations for the evaluation, workup, management, and follow-up of patients with occult primary tumors (cancers of unknown primary). These NCCN Guidelines Insights summarize major discussion points of the 2014 NCCN Occult Primary panel meeting. The panel discussed gene expression profiling (GEP) for the identification of the tissue of origin and concluded that, although GEP has a diagnostic benefit, a clinical benefit has not been demonstrated. The panel recommends against GEP as standard management, although 20% of the panel believes the diagnostic benefit of GEP warrants its routine use. In addition, the panel discussed testing for actionable mutations (eg, ALK) to help guide choice of therapy, but declined to add this recommendation.

  20. Occult sporadic insulinoma: localization and surgical strategy.

    PubMed

    Abboud, Bassam; Boujaoude, Joe

    2008-02-07

    Insulinomas continue to pose a diagnostic challenge to physicians, surgeons and radiologists alike. Most are intrapancreatic, benign and solitary. Biochemical diagnosis is obtained and imaging techniques to localize lesions continue to evolve. Surgical resection is the treatment of choice. Despite all efforts, an occult insulinoma (occult insulinoma refers to a biochemically proven tumor with indeterminate anatomical site before operation) may still be encountered. New localization preoperative techniques decreases occult cases and the knowledge of the site of the mass before surgery allows to determine whether enucleation of the tumor or pancreatic resection is likely to be required and whether the tumor is amenable to removal via a laparoscopic approach. In absence of preoperative localization and intraoperative detection of an insulinoma, blind pancreatic resection is not recommended.

  1. Chiron stellar occultation candidates: 1993-1996

    NASA Technical Reports Server (NTRS)

    Bus, S. J.; Wasserman, L. H.; Elliot, J. L.

    1994-01-01

    A photographic search was conducted for stars that may be occulted by the unusual solar system object (2060) Chiron during the period from fall 1993 through summer 1996. 44 candidates were identified to a limiting V magnitude of 16, and for which the minimum appulse separation with Chiron is predicted to be less than 2.5 arcsec. The successful observation of a stellar occultation by Chiron would give a direct measure of its diameter (currently estimated to be between 60 and 300 km), and would help considerably in constraining Chiron's surface properties and volatile makeup. If at the time of the occultation, Chiron exhibits a significant coma, there is also the potential for measuring the optical-depth profile of the dust in its inner coma.

  2. Using Radio Occultation to probe Earth Atmosphere

    NASA Astrophysics Data System (ADS)

    von Engeln, Axel; Marquardt, Christian

    Radio occultation uses GPS satellite signals to determine atmospheric temperature, pressure, and water vapor profiles. From the first proof of concept mission in the mid 1990s, it has become one of the most successful remote sensing instruments recently added to operational weather forecasting and to the global observing system. The limb sounding geometry provides a high vertical resolution and the measure of time it is based on removes the need for calibration of the data. The assimilation of this kind of data into numerical weather prediction models has identified and removed the bias introduced by several other remote sensing techniques. Within this talk, the concept of radio occultation is introduced and some of its highlights are presented. We focus first on the benefit in numerical weather prediction, but also touch on the potential for climate monitoring. The current constellation of radio occultation instruments and the possible future one are discussed in the final part of the presentation.

  3. Strong scintillations during atmospheric occultations Theoretical intensity spectra. [radio scattering during spacecraft occultations by planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Hinson, D. P.

    1986-01-01

    Each of the two Voyager spacecraft launched in 1977 has completed a reconnaissance of the Jovian and Saturnian systems. In connection with occultation experiments, strong scintillations were observed. Further theoretical work is required before these scintillations can be interpreted. The present study is, therefore, concerned with the derivation of a theory for strong scattering during atmospheric occultation experiments, taking into account as fundamental quantity of interest the spatial spectrum (or spectral density) of intensity fluctuations. Attention is given to a theory for intensity spectra, and numerical calculations. The new formula derived for Phi-i accounts for strong scattering of electromagnetic waves during atmospheric occultations.

  4. Strong scintillations during atmospheric occultations Theoretical intensity spectra. [radio scattering during spacecraft occultations by planetary atmospheres

    NASA Technical Reports Server (NTRS)

    Hinson, D. P.

    1986-01-01

    Each of the two Voyager spacecraft launched in 1977 has completed a reconnaissance of the Jovian and Saturnian systems. In connection with occultation experiments, strong scintillations were observed. Further theoretical work is required before these scintillations can be interpreted. The present study is, therefore, concerned with the derivation of a theory for strong scattering during atmospheric occultation experiments, taking into account as fundamental quantity of interest the spatial spectrum (or spectral density) of intensity fluctuations. Attention is given to a theory for intensity spectra, and numerical calculations. The new formula derived for Phi-i accounts for strong scattering of electromagnetic waves during atmospheric occultations.

  5. [Diagnosis difficulty in occult constrictive pericarditis].

    PubMed

    Massoure, P L; le Bouffos, V; Roubertie, F; Lafitte, S; Roudaut, R

    2005-10-01

    We report the case of a 42 years woman known to have a cardiac heart failure attributed to restrictive cardiomyopathy for want of any other plausible diagnosis. Evolution and repeted investigations finally permitted to rectify the diagnosis by revealing a constrictive pericarditis, remained occult 9 years during. The differentiation of restrictive cardiomyopathy and constrictive pericarditis has been a perennial problem in clinical cardiology. Diagnosis of constrictive pericarditis is based on associated signs sometimes too poor to go straight to thoracotomy. We discuss the mean to approach more precisely this uncommon pattern named occult constrictive pericarditis.

  6. Occultation evidence for an atmosphere on Pluto

    NASA Technical Reports Server (NTRS)

    Hubbard, W. B.; Hunten, D. M.; Dieters, S. W.; Hill, K. M.; Watson, R. D.

    1988-01-01

    Observations from different sources of Pluto occulting a 12th-magnitude star indicate an extended atmosphere around the planet. Here, data obtained from the 1 m telescope at the University of Tasmania, Hobart are interpreted in terms of a theory for occultation by an atmosphere whose thickness is comparable to the planetary radius. The data can be satisfactorily fitted with a methane atmosphere at plausible pressures and temperatures. The surface pressures inferred from this single chord are uncertain by an order of magnitude, but are consistent with spectroscopic constraints.

  7. The Radio Occultation Processing Package ROPP

    NASA Astrophysics Data System (ADS)

    Culverwell, I. D.; Lewis, H. W.; Offiler, D.; Marquardt, C.; Burrows, C. P.

    2015-01-01

    This paper describes the Radio Occultation Processing Package, ROPP, a product of the EUMETSAT Radio Occultation Meteorology Satellite Application Facility (ROM SAF) developed by a large number of scientists over many years. A brief review of the concepts, functionality and structure of ROPP is followed by more detailed descriptions of its key capabilities. Example results from a full chain of processing using some of the ROPP tools are presented. Some current and prospective uses of ROPP are given. Instructions on how to access the code and its supporting documentation are provided.

  8. The Radio Occultation Processing Package, ROPP

    NASA Astrophysics Data System (ADS)

    Culverwell, I. D.; Lewis, H. W.; Offiler, D.; Marquardt, C.; Burrows, C. P.

    2015-04-01

    This paper describes the Radio Occultation Processing Package, ROPP, a product of the EUMETSAT Radio Occultation Meteorology Satellite Application Facility (ROM SAF) developed by a large number of scientists over many years. A brief review of the concepts, functionality and structure of ROPP is followed by more detailed descriptions of its key capabilities. Example results from a full chain of processing using some of the ROPP tools are presented. Some current and prospective uses of ROPP are given. Instructions on how to access the code and its supporting documentation are provided.

  9. Altimetry Using GPS-Reflection/Occultation Interferometry

    NASA Technical Reports Server (NTRS)

    Cardellach, Estel; DeLaTorre, Manuel; Hajj, George A.; Ao, Chi

    2008-01-01

    A Global Positioning System (GPS)- reflection/occultation interferometry was examined as a means of altimetry of water and ice surfaces in polar regions. In GPS-reflection/occultation interferometry, a GPS receiver aboard a satellite in a low orbit around the Earth is used to determine the temporally varying carrier- phase delay between (1) one component of a signal from a GPS transmitter propagating directly through the atmosphere just as the GPS transmitter falls below the horizon and (2) another component of the same signal, propagating along a slightly different path, reflected at glancing incidence upon the water or ice surface.

  10. Evaluation of bone remodeling in regard to the age of scaphoid non-unions

    PubMed Central

    Rein, Susanne; Hanisch, Uwe; Schaller, Hans-Eberhard; Zwipp, Hans; Rammelt, Stefan; Weindel, Stefan

    2016-01-01

    AIM: To analyse bone remodeling in regard to the age of scaphoid non-unions (SNU) with immunohistochemistry. METHODS: Thirty-six patients with symptomatic SNU underwent surgery with resection of the pseudarthrosis. The resected material was evaluated histologically after staining with hematoxylin-eosin (HE), tartrate resistant acid phosphatase (TRAP), CD 68, osteocalcin (OC) and osteopontin (OP). Histological examination was performed in a blinded fashion. RESULTS: The number of multinuclear osteoclasts in the TRAP-staining correlated with the age of the SNU and was significantly higher in younger SNU (P = 0.034; r = 0.75). A higher number of OP-immunoreactive osteoblasts significantly correlated with a higher number of OC-immunoreactive osteoblasts (P = 0.001; r = 0.55). Furthermore, a greater number of OP-immunoreactive osteoblasts correlated significantly with a higher number of OP-immunoreactive multinuclear osteoclasts (P = 0.008; r = 0.43). SNU older than 6 mo showed a significant decrease of the number of fibroblasts (P = 0.04). Smoking and the age of the patients had no influence on bone remodeling in SNU. CONCLUSION: Multinuclear osteoclasts showed a significant decrease in relation to the age of SNU. However, most of the immunhistochemical findings of bone remodeling do not correlate with the age of the SNU. This indicates a permanent imbalance of bone formation and resorption as indicated by a concurrent increase in both osteoblast and osteoclast numbers. A clear histological differentiation into phases of bone remodeling in SNU is not possible. PMID:27458552

  11. Photoelectric observations of lunar occultations. XI

    NASA Astrophysics Data System (ADS)

    Edwards, D. A.; Evans, D. S.; Fekel, F. C.; Smith, B. W.

    1980-04-01

    Occultation observations of 466 events are presented. These include diameter measures of Aldebaran under very bad conditions and a good diameter measure of 82 Vir. The list includes 91 reappearances and observations of 34 double or multiple stars, both new and previously known. The inconsistencies of the observations of Kui 88 are discussed. Further observations are most desirable.

  12. Stellar angular diameters from occultation observations.

    NASA Astrophysics Data System (ADS)

    Qian, B.-C.

    This paper reviews the history of measuring stellar angular diameters from lunar occultation observations and the techniques of data analysis. Several effects which can affect the results of measurement are discussed. The author finds that there may be systematic errors in angular diameters measured by various observatories for Aldebaran.

  13. Photon counts from stellar occultation sources

    NASA Technical Reports Server (NTRS)

    Buglia, James J.

    1987-01-01

    The feasibility of using stars as radiation sources for Earth atmospheric occultation experiments is investigated. Exoatmospheric photon counts of the order of 10 to the 6th power photons/sq cm/sec are realized for the 15 visually brightest stars. Most photon counts appear to be marginally detectable unless photomultiplier or cascade detection devices can be used.

  14. Lunar occultation stellar angular diameter measurements. II

    NASA Astrophysics Data System (ADS)

    Beavers, W. I.; Eitter, J. J.; Cadmus, R. R., Jr.

    1981-09-01

    The results of analyses from 14 of the 200 lunar occultation events observed at the Fick Observatory between November 1972 and January 1975 are reported. These include two measurements with large angular diameters, seven with small or barely resolvable diameters, two point sources, and three cases in which the records are too noisy to allow angular diameter measurements.

  15. Occult carcinoma of the thyroid gland.

    PubMed

    Arellano, L; Ibarra, A

    1984-09-01

    Ten occult carcinomas of the thyroid gland were found in 274 unselected autopsies at the Pathology Service, Hospital José Joaquín Aguirre, between December 1980 and March 1983. This is the lowest incidence among the most recent published series. The present results suggest that environmental factors play an important role in the etiology of this type of carcinoma.

  16. Illinois occultation summary, 1. 1977 - 1978

    NASA Technical Reports Server (NTRS)

    Radick, R.; Lien, D.

    1980-01-01

    Instrumentation and data acquisition techniques used to record lunar occultations at the University of Illinois Prairie Observatory are described. Tables and graphs summarize data from 64 events which include 30 observations of stars brighter than 7th magnitude, 40 reappearances, 4 angular diameter measurements, 8 observations of binary stars, and 6 observations which may indicate multiplicity.

  17. Bone bruise, lipohemarthrosis, and joint effusion in CT of non-displaced hip fracture.

    PubMed

    Geijer, Mats; Dunker, Dennis; Collin, David; Göthlin, Jan H

    2012-03-01

    A suspected occult hip fracture after normal radiography is not uncommon in an elderly person after a fall. Despite a lack of robust validation in the literature, computed tomography (CT) is often used as secondary imaging. To assess the frequency and clinical utility of non-cortical skeletal and soft tissue lesions as ancillary fracture signs in CT diagnosis of occult hip fractures. All fracture signs (cortical and trabecular fractures, bone bruise, joint effusion, and lipohemarthrosis) were recorded in 231 hip low-energy trauma cases with CT performed after normal or equivocal radiography in two trauma centers. There were no fracture signs in 110 patients. Twelve of these had a joint effusion. In 121 patients with 46 cervical hip fractures and 75 trochanteric fractures one or more fracture signs were present. Cortical fractures were found in 115 patients. Bone bruise was found in 119 patients, joint effusion in 35, and lipohemarthrosis in 20 patients. Ancillary signs such as bone bruise and lipohemarthrosis can strengthen and sometimes indicate the diagnosis in CT of occult hip fractures. Joint effusion is a non-specific sign.

  18. Treatment of Scaphoid Waist Nonunion Using Olecranon Bone Graft and Stryker Asnis Micro Cannulated Screw: A Retrospective Study—80 Case Studies and 6 Years of Follow-Up

    PubMed Central

    Poggetti, Andrea; Rosati, Marco; Castellini, Iacopo; Evangelisti, Gisberto; Battistini, Pietro; Parchi, Paolo; Lisanti, Michele

    2015-01-01

    Background Screw fixation and bone grafting are the gold standard for scaphoid waist nonunion without avascular necrosis. Question/Purpose Assesses the scaphoid waist nonunion healing rate with use of an uncommon cancellous bone graft (olecranon) and an unusual fixation system (Asnis Micro Cannulated Screw System; Stryker Inc., Kalamazoo, MI, USA). Material and Methods A series of 102 consecutive patients were treated for scaphoid waist nonunion (without deformity). Of these, 80 patients subjected to clinical (Modified Mayo Wrist Score (MMWS), Jamar hydraulic dynamometer) and radiographic examination before and after surgery were evaluated. Ipsilateral olecranon cancellous bone graft and the ASNIS Micro 3.0-mm diameter screw, were used. The average follow up was 6 years (min 3; max 10). Results Radiographic consolidation was achieved in 90% of patients; dorsal intercalated segment instability (DISI) deformities were corrected in 71.4% of cases. Ninety percent improved the range of motion of the wrist and grip strength. All patients showed a significant reduction of peak force in the operated hand. In 6.25% we observed clinical and radiographic screw head–trapezium impingement. Twenty-six patients developed a degenerative wrist sign. The MMWS yielded 68 optimal, 8 good, and 4 bad results. Conclusions To treat scaphoid waist nonunions without misalignment, low-profile headed screw and olecranon bone graft allowed a high consolidation rate with positive results to long-term follow-up. The Asnis Micro 3.0 mm diameter screw may be a suitable option for treating scaphoid waist nonunion. Level of Evidence IV. PMID:26261746

  19. Treatment of Scaphoid Waist Nonunion Using Olecranon Bone Graft and Stryker Asnis Micro Cannulated Screw: A Retrospective Study-80 Case Studies and 6 Years of Follow-Up.

    PubMed

    Poggetti, Andrea; Rosati, Marco; Castellini, Iacopo; Evangelisti, Gisberto; Battistini, Pietro; Parchi, Paolo; Lisanti, Michele

    2015-08-01

    Background Screw fixation and bone grafting are the gold standard for scaphoid waist nonunion without avascular necrosis. Question/Purpose Assesses the scaphoid waist nonunion healing rate with use of an uncommon cancellous bone graft (olecranon) and an unusual fixation system (Asnis Micro Cannulated Screw System; Stryker Inc., Kalamazoo, MI, USA). Material and Methods A series of 102 consecutive patients were treated for scaphoid waist nonunion (without deformity). Of these, 80 patients subjected to clinical (Modified Mayo Wrist Score (MMWS), Jamar hydraulic dynamometer) and radiographic examination before and after surgery were evaluated. Ipsilateral olecranon cancellous bone graft and the ASNIS Micro 3.0-mm diameter screw, were used. The average follow up was 6 years (min 3; max 10). Results Radiographic consolidation was achieved in 90% of patients; dorsal intercalated segment instability (DISI) deformities were corrected in 71.4% of cases. Ninety percent improved the range of motion of the wrist and grip strength. All patients showed a significant reduction of peak force in the operated hand. In 6.25% we observed clinical and radiographic screw head-trapezium impingement. Twenty-six patients developed a degenerative wrist sign. The MMWS yielded 68 optimal, 8 good, and 4 bad results. Conclusions To treat scaphoid waist nonunions without misalignment, low-profile headed screw and olecranon bone graft allowed a high consolidation rate with positive results to long-term follow-up. The Asnis Micro 3.0 mm diameter screw may be a suitable option for treating scaphoid waist nonunion. Level of Evidence IV.

  20. Cassini Radio Occultation by Enceladus Plume

    NASA Astrophysics Data System (ADS)

    Kliore, A.; Armstrong, J.; Flasar, F.; French, R.; Marouf, E.; Nagy, A.; Rappaport, N.; McGhee, C.; Schinder, P.; Anabtawi, A.; Asmar, S.; Barbinis, E.; Fleischman, D.; Goltz, G.; Aguilar, R.; Rochblatt, D.

    2006-12-01

    A fortuitous Cassini radio occultation by Enceladus plume occurs on September 15, 2006. The occultation track (the spacecraft trajectory in the plane of the sky as viewed from the Earth) has been designed to pass behind the plume (to pass above the south polar region of Enceladus) in a roughly symmetrical geometry centered on a minimum altitude above the surface of about 20 km. The minimum altitude was selected primarily to ensure probing much of the plume with good confidence given the uncertainty in the spacecraft trajectory. Three nearly-pure sinusoidal signals of 0.94, 3.6, and 13 cm-wavelength (Ka-, X-, and S-band, respectively) are simultaneously transmitted from Cassini and are monitored at two 34-m Earth receiving stations of the Deep Space Network (DSN) in Madrid, Spain (DSS-55 and DSS-65). The occultation of the visible plume is extremely fast, lasting less than about two minutes. The actual observation time extends over a much longer time interval, however, to provide a good reference baseline for potential detection of signal perturbations introduced by the tenuous neutral and ionized plume environment. Given the likely very small fraction of optical depth due to neutral particles of sizes larger than about 1 mm, detectable changes in signal intensity is perhaps unlikely. Detection of plume plasma along the radio path as perturbations in the signals frequency/phase is more likely and the magnitude will depend on the electron columnar density probed. The occultation time occurs not far from solar conjunction time (Sun-Earth-probe angle of about 33 degrees), causing phase scintillations due to the solar wind to be the primary limiting noise source. We estimate a delectability limit of about 1 to 3E16 electrons per square meter columnar density assuming about 100 seconds integration time. Potential measurement of the profile of electron columnar density along the occultation track is an exciting prospect at this time.

  1. Elbow Pain After a Fall: Nursemaid's Elbow or Fracture?

    PubMed

    Cohen-Rosenblum, Anna; Bielski, Robert J

    2016-06-01

    Nursemaid's elbow and elbow fractures are both common causes of acute elbow pain, but the mechanism of injury is quite different. In children, falls frequently go unwitnessed and children are often inaccurate when recounting the sequences of a fall, making the mechanism difficult to ascertain. A common clinical mistake is to treat all elbow injuries as a nursemaid's elbow. When the mechanism of injury is unknown, radiographs should be used to help make the diagnosis. Occult fractures, also known as "hairline" elbow fractures, may not be visible on initial X-rays, but clues to the diagnosis, especially the posterior fat pad, can be helpful in evaluation. When an occult fracture is suspected based on history and radiographic findings, the patient's elbow should be immobilized, not manipulated. This article also reviews successful reduction maneuvers for nursemaid's elbow. [Pediatr Ann. 2016;45(6):e214-e217.].

  2. Diagnosis of hip fracture by the auscultatory percussion technique.

    PubMed

    File, P; Wood, J P; Kreplick, L W

    1998-03-01

    Traumatic hip pain is a commonly encountered complaint in the emergency department. Occasionally, initial radiographs fail to show a fracture. A delayed diagnosis can result in significant patient morbidity. Diagnostic algorithms have been formulated to evaluate the patient with hip pain and negative initial radiographs. The auscultatory percussion technique can alert the physician of the presence or absence of an occult hip fracture. Consequently, the physician may order a more sophisticated imaging technique.

  3. Stellar Occultation Probe of Triton's Atmosphere

    NASA Technical Reports Server (NTRS)

    Elliot, James L.

    1998-01-01

    The goals of this research were (i) to better characterize Triton's atmospheric structure by probing a region not well investigated by Voyager and (ii) to begin acquiring baseline data for an investigation of the time evolution of the atmosphere which will set limits on the thermal conductivity of the surface and the total mass of N2 in the atmosphere. Our approach was to use observations (with the Kuiper Airborne Observatory) of a stellar occultation by Triton that was predicted to occur on 1993 July 10. As described in the attached reprint, we achieved these objectives through observation of this occultation and a subsequent one with the KAO in 1995. We found new results about Triton's atmospheric structure from the analysis of the two occultations observed with the KAO and ground-based data. These stellar occultation observations made both in the visible and infrared, have good spatial coverage of Triton including the first Triton central-flash observations, and are the first data to probe the 20-100 km altitude level on Triton. The small-planet light curve model of Elliot and Young (AJ 103, 991-1015) was generalized to include stellar flux refracted by the far limb, and then fitted to the data. Values of the pressure, derived from separate immersion and emersion chords, show no significant trends with latitude indicating that Triton's atmosphere is spherically symmetric at approximately 50 km altitude to within the error of the measurements. However, asymmetry observed in the central flash indicates the atmosphere is not homogeneous at the lowest levels probed (approximately 20 km altitude). From the average of the 1995 occultation data, the equivalent-isothermal temperature of the atmosphere is 47 +/- 1 K and the atmospheric pressure at 1400 km radius (approximately 50 km altitude) is 1.4 +/- 0.1 microbar. Both of these are not consistent with a model based on Voyager UVS and RSS observations in 1989 (Strobel et al, Icarus 120, 266-289). The atmospheric

  4. Distal Radius Radiographic Indices and Perilunate Fracture Dislocation

    PubMed Central

    Bagherifard, Abolfazl; Jafari, Davod; Keihan Shokouh, Hassan; Motavallian, Ebrahim; Najd Mazhar, Farid

    2016-01-01

    Background Distal radius radiographic indices may play a role as risk factors in pathogenesis of Kienbock’s disease, scaphoid fracture and nonunion. Perilunate fracture dislocations are devastating wrist injuries, and their relationship and distal radius indices have not been addressed in the literature. Objectives The aim of this study was to evaluate the possible role of distal radius radiographic indices including radial height, radial inclination, ulnar variance and volar tilt as risk factors in the perilunate fracture dislocation injury of the wrist. Patients and Methods We studied distal radius radiographic indices including radial height, radial inclination, ulnar variance and volar tilt in 43 patients with perilunate fracture dislocations and compared them with 44 wrists in the control group. Results The mean values of the radial height, radial inclination, ulnar variance and volar tilt were 12.74 (5 - 18), 24.20 (7 - 35), -0.73 (-5 - 4) and 12.28 (2 - 20) in the patient group. These values were 12.68 (9 - 22), 23.22 (17 - 30), -0.11 (-4 - 3) and 11.05 (-3 - 20), respectively in the control group. There was no statistically significant difference between the two groups. Conclusions This study did not show that distal radius anatomical indices including the radial height, radial inclination, ulnar variance and volar tilt influence perilunate fracture dislocation as risk factors. PMID:27626004

  5. Current methods of radio occultation data inversion

    NASA Technical Reports Server (NTRS)

    Kliore, A. J.

    1972-01-01

    The methods of Abel integral transform and ray-tracing inversion have been applied to data received from radio occultation experiments as a means of obtaining refractive index profiles of the ionospheres and atmospheres of Mars and Venus. In the case of Mars, certain simplifications are introduced by the assumption of small refractive bending in the atmosphere. General inversion methods, independent of the thin atmosphere approximation, have been used to invert the data obtained from the radio occultation of Mariner 5 by Venus; similar methods will be used to analyze data obtained from Jupiter with Pioneers F and G, as well as from the other outer planets in the Outer Planet Grand Tour Missions.

  6. [Chronic hepatitis and occult HCV infection].

    PubMed

    Kowala-Piaskowska, Arleta; Mozer-Lisewska, Iwona; Pham, Tram N Q; Michalak, Tomasz I

    2010-01-01

    Hepatitis C virus (HCV) was discovered in 1989. HCV is a positive single-strand RNA. We all have thought, that HCV can replicate only in liver tissue, but now we know, that HCV can replicate in extrahepatic tissue as well. In about 48-86% of HCV infected patients, chronic hepatitis C (CHC) has been noticed and eventually, after tens of years, liver insufficiency, cirrhosis or hepatocellular carcinoma. The current recommended treatment for CHC is a combination of pegylated-interferon alpha and Ribavirin. Presently it is known, that HCV infection can persist as an occult infection. RNA HCV can be detected in patients after successful treatment for CHC or spontaneous elimination. Persistent HCV replication in hepatocytes or lymphoid cells would likely lead to continuous antigenic stimulation of the immune system. This prolonged replication may contribute to the immune tolerance of HCV, impairment of immune response and even further virus persistence. This occult infection grows more important in transplantation.

  7. Stress Fractures

    MedlinePlus

    Stress fractures Overview By Mayo Clinic Staff Stress fractures are tiny cracks in a bone. They're caused by ... up and down or running long distances. Stress fractures can also arise from normal use of a ...

  8. Greenstick Fractures

    MedlinePlus

    Greenstick fractures Overview By Mayo Clinic Staff A greenstick fracture occurs when a bone bends and cracks, instead of breaking completely into separate pieces. The fracture looks similar to what happens when you try ...

  9. Potential KBO Stellar Occultations: 2011-2015

    NASA Astrophysics Data System (ADS)

    Zangari, Amanda; Zuluaga, C. A.; Gulbis, A. A. S.; Elliot, J. L.; Person, M. J.; Bosh, A. S.

    2010-10-01

    We present the results of an occultation candidate search of the UCAC2 catalog for over 30 Kuiper Belt Objects and Centaurs [not including (134340) Pluto]. KBOs were selected based on absolute magnitude, distance from the sun and the number of oppositions observed. This search identified occultation candidate stars within 2.5 arcseconds of each minor planet's path from 2011-2015. As typical UCAC2 catalog uncertainties ranged from 0.05 to 0.5 arcseconds, and KBO ephemeris uncertainties for a well-observed object ranged from 0.2 to 0.6 arcseconds, this study seeks to identify the most promising potential occultations for further astrometric follow-up. Additional observations of stars and the potentially occulting body help determine the necessary star offsets and ephemeris corrections. Events have been grouped into the following categories: near-geocentric (any brightness), near-misses, stars of magnitude 13 or brighter (the dimmest star feasible with a large portable telescope), slow events, and events observable from telescope-rich regions of the Earth. These categories allow for planning campaigns involving wide-spread portable and fixed telescopes, or an airborne telescope (such as SOFIA). The two most promising events are an encounter of (28978) Ixion with a 10.63 magnitude star on 2012-04-16 and (84922) 2003 VS2 with a 14.83 magnitude star on 2011-11-01. KBOs such as (50000) Quaoar, (28978) Ixion, (55638) 2002 VE95, and (84922) 2003 VS2 encounter over 50 UCAC2 stars in the next five years and should be most carefully monitored. This work was supported, in part by NASA Grant NNX10AB27G.

  10. Studies of planetary upper atmospheres through occultations

    NASA Technical Reports Server (NTRS)

    Elliot, J. L.

    1982-01-01

    The structure, composition, dynamics and energy balance of planetary upper atmospheres through interpretation of steller occultation data from Uranus is discussed. The wave-optical problem of modelling strong scintillation for arbitrary turbulent atmospheres is studied, as well as influence of turbulence. It was concluded that quasi-global features of atmospheric structure are accurately determined by numerical inversion. Horizontally inhomogeneous structures are filtered out and have little effect on temperature profiles.

  11. The JWST/NIRCam Coronagraph Flight Occulters

    NASA Technical Reports Server (NTRS)

    Krist, John E.; Balasubramanian, Kunjithapatham; Muller, Richard E.; Shaklan, Stuart B.; Kelly, Douglas M.; Wilson, Daniel W.; Beichman, Charles A.; Serabyn, Eugene; Mao, Yalan; Echternach, Pierre M.; hide

    2010-01-01

    The NIRCam instrument on the James Webb Space Telescope will have a Lyot coronagraph for high contrast imaging of extrasolar planets and circumstellar disks at lambda = 2 - 5 micrometers. Half-tone patterns are used to create graded-transmission image plane masks. These are generated using electron beam lithography and reactive ion etching of a metal layer on an antireflection coated sapphire substrate. We report here on the manufacture and evaluation of the flight occulters.

  12. Study of transneptunian objects through stellar occultations

    NASA Astrophysics Data System (ADS)

    Benedetti-Rossi, G.; Sicardy, B.; Braga-Ribas, F.

    2014-07-01

    The physical parameters of the transneptunian objects (TNO's) such as size, shape, density, presence of atmosphere, provide important information on their formation and evolution. At more than 30 astronomical units (au) from the Sun, those objects receive low solar radiation and have low mutual collisions so they can be considered as remnants of the primordial outer Solar System. Besides that, information on TNO's is of great relevance when trying to establish a general formation scenario for the recently discovered planetary systems. The problem is that such bodies have a diameter smaller than 2300 km (Eris, one of the largest TNO, has 2326 km) and, when viewed from Earth, they subtend angles smaller than 50 milli-arcseconds, a fact that makes their resolution very poor with current imaging systems. One method to obtain very accurate information on the TNO's is the stellar-occultation technique. Sizes at kilometer accuracies and pressure at nanobar levels can be achieved with this method. Shape, mass, density and other physical parameters can also be derived using this technique. Since 2010, we observed stellar occultations of several TNO's (Varuna in 2010 and 2013; Eris in 2010; 2003 AZ_{84} in 2010 and 2011; Makemake in 2011; Quaoar in 2011 and two in 2012; 2002 KX_{14} in 2013; and finally Sedna in 2013) besides some other occultations of the Pluto system and of the largest Centaurs. We also predicted future events in 2014 and 2015 for the largest 40 TNO's and Centaurs. In this work, we will present new results obtained from recent stellar occultations of TNO's.

  13. The JWST/NIRCam Coronagraph Flight Occulters

    NASA Technical Reports Server (NTRS)

    Krist, John E.; Balasubramanian, Kunjithapatham; Muller, Richard E.; Shaklan, Stuart B.; Kelly, Douglas M.; Wilson, Daniel W.; Beichman, Charles A.; Serabyn, Eugene; Mao, Yalan; Echternach, Pierre M.; Trauger, John T.; Liewer, Kurt M.

    2010-01-01

    The NIRCam instrument on the James Webb Space Telescope will have a Lyot coronagraph for high contrast imaging of extrasolar planets and circumstellar disks at lambda = 2 - 5 micrometers. Half-tone patterns are used to create graded-transmission image plane masks. These are generated using electron beam lithography and reactive ion etching of a metal layer on an antireflection coated sapphire substrate. We report here on the manufacture and evaluation of the flight occulters.

  14. Asteroidal occultation timed by four UK observers

    NASA Astrophysics Data System (ADS)

    McGee, H.

    2000-04-01

    The occultation of a 9th magnitude star by the minor planet (49) Pales at 01.00 on Monday January 17 was the first such event to be timed by more than one observer at different locations on the track in the UK (see Figure 1). It was also seen from Hungary, and by three sets of observers in Canada and the USA, but unfortunately heavy cloud prevented observation across most of Europe.

  15. CASSINI UVIS STELLAR OCCULTATION OBSERVATIONS OF SATURN's RINGS

    SciTech Connect

    Colwell, J. E.; Jerousek, R. G.; Pettis, D.; Bradley, E. T.; Esposito, L. W.; Sremcevic, M.

    2010-12-15

    The Cassini spacecraft's Ultraviolet Imaging Spectrograph (UVIS) includes a high-speed photometer (HSP) that has observed more than 100 stellar occultations by Saturn's rings. Here, we document a standardized technique applied to the UVIS-HSP ring occultation datasets delivered to the Planetary Data System as higher level data products. These observations provide measurements of ring structure that approaches the scale of the largest common ring particles ({approx}5 m). The combination of multiple occultations at different viewing geometries enables reconstruction of the three-dimensional structure of the rings. This inversion of the occultation data depends on accurate calibration of the data so that occultations of different stars taken at different times and under different viewing conditions can be combined to retrieve ring structure. We provide examples of the structure of the rings as seen from several occultations at different incidence angles to the rings, illustrating changes in the apparent structure with viewing geometry.

  16. Stellar occultations by large Transneptunian Objects (dwarf planets candidates)

    NASA Astrophysics Data System (ADS)

    Müller, Thomas G.

    2013-10-01

    Occultations of stars by Transneptunian Objects (TNOs) had never been observed (except for Pluto-Charon system), but in slightly more than three years, 12 such occultations have been detected. This has been a breakthrough. Stellar occultations allow us to derive accurate diameters, shapes and albedos of TNOs. Besides, the presence of atmospheres can be determined and the orbits can be refined. We request two attempts to observe occultations with SOFIA / HIPO during Cycle 2. Occultations by TNOs are brief and the uncertainties in timing require only around 0.33 hrs of observations per alert. The predictions only become accurate enough around 1 or 2 weeks prior to the occultation. This is why a target of opportunity proposal with SOFIA / HIPO is requested.

  17. Novel Presentation of Uncommon Wrist Injury: Simultaneous Lunate and Perilunate Fracture Dislocation (scapho-capitate Syndrome) of Both Wrists

    PubMed Central

    Bhat, Anil K.; A, Nishanth; Acharya, Ashwath; Kumar, Yogesh

    2016-01-01

    Introduction: Perilunate and lunate dislocations are uncommon high energy injuries and have extensive soft tissue, cartilaginous and bony damage. The most common pattern is trans-scaphoid perilunate fracture dislocation which constitutes approximately 50% of these injuries. Unusual injury pattern like Scaphocapitate syndrome can occur with fracture through scaphoid waist and capitate that rotates the proximal capitate 180° so that its proximal articular surface points distally. With this case report, we would like to present a novel presentation of an uncommon wrist injury. Case report: We present a case of simultaneous lunate dislocation in one wrist and perilunate fracture dislocation (Scapho- capitate syndrome) in the contralateral wrist which occurred simultaneously in a young male following a two wheeler accident. The injury was missed initially at the primary treating centre. Upon diagnosis, the patient underwent open reduction and internal fixation along with ligament repair. The patient was subsequently followed up for a period of four years and was found to have very good clinical and radiological outcome. Conclusion: These injuries occurring simultaneously in contralateral wrists are exceptionally rare and unusual as the mechanisms of injury are different. These are high velocity injuries and are often missed, especially in presence of other major injuries. These high energy injuries need accurate diagnosis, early and aggressive treatment in order to prevent complications PMID:27703938

  18. [Occult hepatitis B virus infection in chronic hepatitis C].

    PubMed

    Jang, Jae Young; Park, Eui Ju

    2013-09-01

    Occult HBV infection is defined as the presence of HBV DNA in the liver (with or without detectable or undetectable HBV DNA in the serum) of individuals testing negative for HBsAg. Studies on occult HBV infection in hepatitis C patients have reported highly variable prevalence, because the prevalence of occult HBV infection varies depending on the hepatitis B risk factors and methodological approaches. The most reliable diagnostic approach for detecting occult HBV detection is through examination of liver DNA extracts. HCV has been suspected to strongly suppress HBV replication up to the point where it may be directly responsible for occult HBV infection development. However, more data are needed to arrive at a definitive conclusion regarding the role of HCV in inducing occult HBV infection. Occult HBV infection in chronic hepatitis C patients is a complex biological entity with possible relevant clinical implications. Influence of occult HBV infection on the clinical outcomes of chronic hepatitis C may be considered negative. However, recent studies have shown that occult HBV infection could be associated with the development of hepatocellular carcinoma and contribute to the worsening of the course of chronic liver disease over time in chronic hepatitis C patients. Nevertheless, the possible role of occult HBV infection in chronic hepatitis C is still unresolved and no firm conclusion has been made up until now. It still remains unclear how occult HBV infection affects the treatment of chronic hepatitis C. Therefore, in order to resolve current controversies and understand the pathogenic role and clinical impacts of occult HBV infection in chronic hepatitis C patients, well-designed clinical studies are needed.

  19. On the reduction of occultation light curves. [stellar occultations by planets

    NASA Technical Reports Server (NTRS)

    Wasserman, L.; Veverka, J.

    1973-01-01

    The two basic methods of reducing occultation light curves - curve fitting and inversion - are reviewed and compared. It is shown that the curve fitting methods have severe problems of nonuniqueness. In addition, in the case of occultation curves dominated by spikes, it is not clear that such solutions are meaningful. The inversion method does not suffer from these drawbacks. Methods of deriving temperature profiles from refractivity profiles are then examined. It is shown that, although the temperature profiles are sensitive to small errors in the refractivity profile, accurate temperatures can be obtained, particularly at the deeper levels of the atmosphere. The ambiguities that arise when the occultation curve straddles the turbopause are briefly discussed.

  20. Shock wave therapy of fracture nonunion.

    PubMed

    Alkhawashki, Hazem M I

    2015-11-01

    We have used the principles of extracorporeal shock wave therapy (ESWT) in the treatment of nonunion of fractures in 44 patients (49 bones).There were 35 males and 9 females with a mean age of 34 years(range14-70). Clinical and radiological assessment was performed at regular time intervals with a minimum follow up of 18 months. Most common sites involved were the femur and tibia. The average time from initial fracture treatment to intervention with ESWT was 11.9 months (6 months to 5 years). Thirty eight non-union sites had one session of treatment and the rest (11) had more than one session. Union was successful in 75.5% of cases at a mean time of 10.2 months (range 3-19). Failure in the remaining cases was due to more than 5mm gap, instability, compromised vascularity (type of bone) and deep low grade infection; which was discovered at the time of surgical intervention when no signs of radiological healing occurred after 6 months from treatment. Failing sites were shaft of femur, scaphoid, neck of humerus and neck of femur. No local complications were observed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. The Northrop Grumman External Occulter Testbed: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Lo, Amy; Glassman, T.; Lillie, C.

    2007-05-01

    We have built a subscale testbed to demonstrate and validate the performance of the New Worlds Observer (NWO), a terrestrial planet finder external-occulter mission concept. The external occulter concept allows observations of nearby exo-Earths using two spacecraft: one carrying an occulter that is tens of meters in diameter and the other carrying a generic space telescope. The occulter is completely opaque, resembling a flower, with petals having a hypergaussian profile that enable 10-10 intensity suppression of stars that potentially harbor terrestrial planets. The baseline flight NWO system has a 30 meter occulter flying 30,000 km in front of a 4 meter class telescope. Testing the flight configuration on the ground is not feasible, so we have matched the Fresnel number of the flight configuration ( 10) using a subscale occulter. Our testbed consists of an 80 meter length evacuated tube, with a high precision occulter in the center of the tube. The occulter is 4 cm in diameter, manufactured with ¼ micron metrological accuracy and less than 2 micron tip truncation. This mimics a 30 meter occulter with millimeter figure accuracy and less than centimeter tip truncation. Our testbed is an evolving experiment, and we report here the first, preliminary, results using a single wavelength laser (532 nm) as the source.

  2. Io hot spots - Infrared photometry of satellite occultations

    NASA Technical Reports Server (NTRS)

    Goguen, J. D.; Matson, D. L.; Sinton, W. M.; Howell, R. R.; Dyck, H. M.

    1988-01-01

    Io's active hot spots, which are presently mapped on the basis of IR photometry of this moon's occultation by other Gallilean satellites, are obtained with greatest spatial resolution near the sub-earth point. A model is developed for the occultation lightcurves, and its fitting to the data defines the apparent path of the occulting satellite relative to Io; the mean error in apparent relative position of occulting satellites is of the order of 178 km. A heretofore unknown, 20-km diameter hot spot is noted on Io's leading hemisphere.

  3. Boundary diffraction wave integrals for diffraction modeling of external occulters.

    PubMed

    Cady, Eric

    2012-07-02

    An occulter is a large diffracting screen which may be flown in conjunction with a telescope to image extrasolar planets. The edge is shaped to minimize the diffracted light in a region beyond the occulter, and a telescope may be placed in this dark shadow to view an extrasolar system with the starlight removed. Errors in position, orientation, and shape of the occulter will diffract additional light into this region, and a challenge of modeling an occulter system is to accurately and quickly model these effects. We present a fast method for the calculation of electric fields following an occulter, based on the concept of the boundary diffraction wave: the 2D structure of the occulter is reduced to a 1D edge integral which directly incorporates the occulter shape, and which can be easily adjusted to include changes in occulter position and shape, as well as the effects of sources-such as exoplanets-which arrive off-axis to the occulter. The structure of a typical implementation of the algorithm is included.

  4. Several Well-observed Asteroidal Occultations in 2010

    NASA Astrophysics Data System (ADS)

    Timerson, Brad; Durech, J.; Abramson, H.; Brooks, J.; Caton, D.; Clark, D.; Conard, S.; Cooke, B.; Dunham, D. W.; Dunham, J.; Edberg, S.; Ellington, C.; Faircloth, J.; Herchak, S.; Iverson, E.; Jones, R.; Lucas, G.; Lyzenga, G.; Maley, P.; Martinez, L.; Menke, J.; Mroz, G.; Nolan, P.; Peterson, R.; Preston, S.; Rattley, G.; Ray, J.; Scheck, A.; Stamm, J.; Stanton, R.; Suggs, R.; Tatum, R.; Thomas, W.

    2011-10-01

    During 2010 IOTA observers in North America reported about 190 positive observations for 106 asteroid occultation events. For several asteroids, this included observations with multiple chords. For two events, an inversion model was available. An occultation by 16 Psyche on 2010 August 21 yielded a best-fit ellipse of 235.4 x 230.4 km. On 2010 December 24, an occultation by 93 Minerva produced a best-fit ellipse of 179.4 x 133.4 km. An occultation by 96 Aegle on 2010 October 29 yielded a best-fit ellipse of 124.9 x 88.0 km. An occultation by 105 Artemis on 2010 June 24 showed a best-fit ellipse of 125.0 x 92.0 km. An occultation by 375 Ursula on 2010 December 4 produced a best-fit ellipse of 125.0 km x 135.0 km. Of note are two events not summarized in this article. On 2010 August 31, an occultation by 695 Bella yielded a new double star. That event will be summarized in the JDSO. Finally, on 2010 April 6, an occultation of zeta Ophiuchi by 824 Anastasia was observed by 65 observers at 69 locations. Unfortunately a large shift in the path yielded only 4 chords. Results of that event, and all the events mentioned here, can be found on the North American Asteroidal Occultation Results web page.

  5. Hip fracture: diagnosis, treatment, and secondary prevention.

    PubMed

    LeBlanc, Kim Edward; Muncie, Herbert L; LeBlanc, Leanne L

    2014-06-15

    Hip fractures cause significant morbidity and are associated with increased mortality. Women experience 80% of hip fractures, and the average age of persons who have a hip fracture is 80 years. Most hip fractures are associated with a fall, although other risk factors include decreased bone mineral density, reduced level of activity, and chronic medication use. Patients with hip fractures have pain in the groin and are unable to bear weight on the affected extremity. During the physical examination, displaced fractures present with external rotation and abduction, and the leg will appear shortened. Plain radiography with cross-table lateral view of the hip and anteroposterior view of the pelvis usually confirms the diagnosis. If an occult hip fracture is suspected and plain radiography is normal, magnetic resonance imaging should be ordered. Most fractures are treated surgically unless the patient has significant comorbidities or reduced life expectancy. The consulting orthopedic surgeon will choose the surgical procedure. Patients should receive prophylactic antibiotics, particularly against Staphylococcus aureus, before surgery. In addition, patients should receive thromboembolic prophylaxis, preferably with low-molecular-weight heparin. Rehabilitation is critical to long-term recovery. Unless contraindicated, bisphosphonate therapy should be used to reduce the risk of another hip fracture. Some patients may benefit from a fall-prevention assessment.

  6. Neglected trans-scaphoid trans-styloid volar dislocation of the lunate. Late result following open reduction and K-wire fixation.

    PubMed

    Givissis, P; Christodoulou, A; Chalidis, B; Pournaras, J

    2006-05-01

    A rare case of radiocarpal dislocation is presented. The lunate and proximal pole of the scaphoid were displaced in a volar and proximal direction. The injury was missed initially and the patient was subsequently operated on six weeks later. Open reduction and internal fixation of the scaphoid was performed and this was followed by an uneventful postoperative period, with a satisfactory functional outcome at the eight-year follow-up, despite carpal instability non-dissociative-dorsal intercalated segmental instability configuration of the carpus. We believe that although open reduction in neglected cases carries the potential risks of avascular necrosis and nonunion of the affected carpal bones, an attempt should be made to restore the anatomy of the carpus.

  7. UMBRAS: a matched occulter and telescope for imaging extrasolar planets

    NASA Astrophysics Data System (ADS)

    Schultz, Alfred B.; Jordan, Ian J.; Kochte, Mark; Fraquelli, Dorothy A.; Bruhweiler, Fred; Hollis, Jan M.; Carpenter, Kenneth G.; Lyon, Richard G.; DiSanti, Mike A.; Miskey, Cherie L.; Leitner, Jesse; Burns, Richard D.; Starin, Scott R.; Rodrigue, Melodi; Fadali, M. S.; Skelton, Dennis L.; Hart, Helen M.; Hamilton, Forrest C.; Cheng, Kwang-Ping

    2003-02-01

    We describe a 1-meter space telescope plus free-flying occulter craft mission that would provide direct imaging and spectroscopic observations of Jovian and Uranus-sized planets about nearby stars not detectable by Doppler techniques. The Doppler technique is most sensitive for the detection of massive, close-in extrasolar planets while the use of a free-flying occulter would make it possible to image and study stellar systems with planets comparable to our own Solar System. Such a mission with a larger telescope has the potential to detect earth-like planets. Previous studies of free-flying occulters reported advantages in having the occulting spot outside the telescope compared to a classical coronagraph onboard a space telescope. Using an external occulter means light scatter within the telescope is reduced due to fewer internal obstructions and less light entering the telescope and the polishing tolerances of the primary mirror and the supporting optics can be less stringent, thereby providing higher contrast and fainter detection limits. In this concept, the occulting spot is positioned over the star by translating the occulter craft, at distances of 1,000 to 15,000 kms from the telescope, on the sky instead of by moving the telescope. Any source within the telescope field-of-view can be occulted without moving the telescope. In this paper, we present our current concept for a 1-m space telescope matched to a free-flying occulter, the Umbral Missions Blocking Radiating Astronomical Sources (UMBRAS) space mission. An UMBRAS space mission consists of a Solar Powered Ion Driven Eclipsing Rover (SPIDER) occulter craft and a matched (apodized) telescope. The occulter spacecraft would be semi-autonomous, with its own propulsion systems, internal power (solar cells), communications, and navigation capability. Spacecraft rendezvous and formation flying would be achieved with the aid of telescope imaging, RF or laser ranging, celestial navigation inputs, and formation

  8. New perspectives in occult hepatitis C virus infection.

    PubMed

    Carreño, Vicente; Bartolomé, Javier; Castillo, Inmaculada; Quiroga, Juan Antonio

    2012-06-21

    Occult hepatitis C virus (HCV) infection, defined as the presence of HCV RNA in liver and in peripheral blood mononuclear cells (PBMCs) in the absence of detectable viral RNA in serum by standard assays, can be found in anti-HCV positive patients with normal serum levels of liver enzymes and in anti-HCV negative patients with persistently elevated liver enzymes of unknown etiology. Occult HCV infection is distributed worldwide and all HCV genotypes seem to be involved in this infection. Occult hepatitis C has been found not only in anti-HCV positive subjects with normal values of liver enzymes or in chronic hepatitis of unknown origin but also in several groups at risk for HCV infection such as hemodialysis patients or family members of patients with occult HCV. This occult infection has been reported also in healthy populations without evidence of liver disease. Occult HCV infection seems to be less aggressive than chronic hepatitis C although patients affected by occult HCV may develop liver cirrhosis and even hepatocellular carcinoma. Thus, anti-HCV negative patients with occult HCV may benefit from antiviral therapy with pegylated-interferon plus ribavirin. The persistence of very low levels of HCV RNA in serum and in PBMCs, along with the maintenance of specific T-cell responses against HCV-antigens observed during a long-term follow-up of patients with occult hepatitis C, indicate that occult HCV is a persistent infection that is not spontaneously eradicated. This is an updated report on diagnosis, epidemiology and clinical implications of occult HCV with special emphasis on anti-HCV negative cases.

  9. Examination under anesthetic for occult pelvic ring instability.

    PubMed

    Sagi, H Claude; Coniglione, Franco M; Stanford, Jason H

    2011-09-01

    anteroposterior compression (APC or OTA 61-B1) injuries and 31 lateral compression (LC or OTA 61-B2) injuries were evaluated. Of the 14 pelvic ring injuries initially classified as an APC-1, seven (50%) were deemed stable and treated nonsurgically, whereas seven (50%) were felt to have sufficient instability (an occult APC-2) to warrant treatment with anterior fixation based on EUA. Of the 23 injuries initially classified as an APC-2, all but one required surgical fixation: 13 (57%) were treated with anterior fixation alone (APC-2a), whereas nine (39%) were treated with anterior fixation and supplemental iliosacral screw placement (APC-2b) based on the degree of instability noted during the EUA. Of the 20 injuries initially classified as an LC-1, 13 (65%) were stable and treated nonsurgically (LC-1a), whereas seven (35%) were treated with anterior and/or posterior stabilization (LC-1b) based on the degree of instability noted during the EUA. The reported incidence of poor functional outcomes associated with pelvic fracture may be attributable, in part, to inadequate treatment of misdiagnosed injuries and chronic instability and/or malunion. Performing an examination under anesthesia with dynamic stress fluoroscopy as described in this series revealed occult instability in 50% of presumed APC-1 injuries, 39% of APC-2 injuries, and 37% of LC-1 injuries. We propose a modification to the Young-Burgess Classification system to reflect the dynamic component of pelvic ring instability disclosed on EUA as follows: APC-2a for those injuries requiring anterior only fixation, APC-2b for those injuries that may require treatment with anterior and posterior fixation, LC-1a for those injuries that are stable and do not require internal fixation, and LC-1b for those lateral compression injuries that may require treatment with internal fixation. We conclude that pelvic EUA merits further analysis as an important diagnostic tool that may provide additional information regarding instability of the

  10. Cerebral Venous Air Embolism due to a Hidden Skull Fracture Secondary to Head Trauma

    PubMed Central

    Hosaka, Ai; Yamaguchi, Tetsuto; Yamamoto, Fumiko; Shibagaki, Yasuro

    2015-01-01

    Cerebral venous air embolism is sometimes caused by head trauma. One of the paths of air entry is considered a skull fracture. We report a case of cerebral venous air embolism following head trauma. The patient was a 55-year-old man who fell and hit his head. A head computed tomography (CT) scan showed the air in the superior sagittal sinus; however, no skull fractures were detected. Follow-up CT revealed a fracture line in the right temporal bone. Cerebral venous air embolism following head trauma might have occult skull fractures even if CT could not show the skull fractures. PMID:26693366

  11. 21 CFR 864.6550 - Occult blood test.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Occult blood test. 864.6550 Section 864.6550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6550 Occult blood test....

  12. The Treatment of the Occult in General Encyclopedias.

    ERIC Educational Resources Information Center

    Sonnenfeld, Gary F.

    This paper is a content analysis of three general encyclopedias, "Encyclopedia Americana" (EA), "Encyclopaedia Brittanica" (EB), and "World Book Encyclopedia" (WBC), which quantifies the treatment of the occult. Entries are selected from each by starting with the article "Occultism" and tracing all…

  13. Occultations by Uranus and Neptune - 1991-1999

    NASA Technical Reports Server (NTRS)

    Klemola, Arnold R.; Mink, Douglas J.

    1991-01-01

    The results of a photographic plate search are presented for stars as faint as mv = 14 which may be occulted by Uranus or Neptune or their rings between January 1, 1991 and December 31, 1999. Circumstances for the closest approach of Uranus to 76 stars and Neptune to 18 stars are presented. Occultations by Neptune's ring 'arcs' are predicted in 1992, 1997, and 1999.

  14. [Contribution of quantitative radio-scintigraphy to diagnosis of wrist injuries undetected on plain films: a prospective study of 154 cases].

    PubMed

    Lepage, D; Obert, L; Garbuio, P; Tropet, Y; Paratte, B; Runge, M; Verdenet, J; Cardot, J C

    2004-10-01

    Fractures of the scaphoid must be diagnosed quickly to avoid persistent nonunion and the risk of osteoarthritis. Despite meticulous physical examination and adequate x-ray detection, numerous occult fractures still go unrecognized. The aim of this prospective study was to analyze the pertinence of quantitative radio-scintigraphy (QRS) presently used for the diagnosis of occult wrist fractures. Quantitative radio-scintigraphy (QRS) is a new imaging technique associating quantitative bone scan and numerical fusion between bone scan images and x-ray images. We conducted a prospective study between November 1994 and March 1999 to evaluate the pertinence of this examination technique for the diagnosis of occult wrist fractures in patients presenting clinical symptoms suggestive of wrist fracture but whose plain x-rays were initially considered normal. Further some patients had several series of plain x-rays performed at several week intervals in order to search for fractures becoming progressively visible on plain x-rays. After the QRS data was acquired, these patients' x-rays were reviewed again. We also compared the cost of QRS, repeated x-rays, bone scan and MRI at the Besançon University Hospital. QRS was performed in all 154 patients and revealed 61 fractures (56 single-line and 5 multiple-line fractures). Thus 43.5% of these patients had occult wrist fractures (41% of which involved the carpal scaphoid). Occult fracture of the wrist, particularly the carpal scaphoid, is frequent. Repeated x-ray examination does not increase the rate of detection of these fractures. Bone scans may also fail to reveal occult fractures. MRI is a key examination in the assessment of wrist fracture symptoms, but is presently not available in all institutions. Bone scan is classically insufficiently precise. QRS is a rapidly available low-cost examination which we have found to be indispensable for the diagnosis of occult wrist fractures. With early QRS diagnosis, the risk of neglected

  15. Retrieval Algorithms for the Halogen Occultation Experiment

    NASA Technical Reports Server (NTRS)

    Thompson, Robert E.; Gordley, Larry L.

    2009-01-01

    The Halogen Occultation Experiment (HALOE) on the Upper Atmosphere Research Satellite (UARS) provided high quality measurements of key middle atmosphere constituents, aerosol characteristics, and temperature for 14 years (1991-2005). This report is an outline of the Level 2 retrieval algorithms, and it also describes the great care that was taken in characterizing the instrument prior to launch and throughout its mission life. It represents an historical record of the techniques used to analyze the data and of the steps that must be considered for the development of a similar experiment for future satellite missions.

  16. Vascularized bone grafts for the treatment of carpal bone pathology.

    PubMed

    Derby, Brian M; Murray, Peter M; Shin, Alexander Y; Bueno, Reuben A; Mathoulin, Christophe L; Ade, Tim; Neumeister, Michael W

    2013-03-01

    Primary bone healing fails to occur in 5-15 % of scaphoid bones that undergo fracture fixation. Untreated, occult fractures result in nonunion up to 12 % of the time. Conventional bone grafting is the accepted management in the treatment algorithm of scaphoid nonunion if the proximal pole is vascularized. Osteonecrosis of the proximal scaphoid pole intuitively suggests a need for transfer of the vascularized bone to the nonunion site. Scaphoid nonunion treatment aims to prevent biological and mechanical subsidence of the involved bone, destabilization of the carpus, and early degenerative changes associated with scaphoid nonunion advanced collapse. Pedicled distal radius and free vascularized bone grafts (VBGs) offer hand surgeons an alternative treatment option in the management of carpal bone nonunion. VBGs are also indicated in the treatment of avascular necrosis of the scaphoid (Preiser's disease), lunate (Kienböck's disease), and capitate. Relative contraindications to pedicled dorsal radius vascularized bone grafting include humpback deformity, carpal instability, or collapse. The free medial femoral condyle bone graft has offered a novel treatment option for the humpback deformity to restore geometry of the carpus, otherwise not provided by pedicled grafts. In general, VBGs are contraindicated in the setting of a carpal bone without an intact cartilaginous shell, in advanced carpal collapse with degenerative changes, and in attempts to salvage small or collapsed bone fragments. Wrist salvage procedures are generally accepted as the more definitive treatment option under such circumstances. This manuscript offers a current review of the techniques and outcomes of VBGs to the carpal bones.

  17. Precise Astrometry for Predicting Kuiper Belt Object Occultations

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott; Elliot, James; Kern, Susan; Zuluaga, Carlos; Gulbis, Amanda

    2010-02-01

    In order to observe an occultation of a bright star by a Kuiper Belt object the event must first be predicted as to where and when it will happen. These predictions require precise astrometry every few months of the largest Kuiper Belt objects. Through the occultation events the diameters, possible companions and possible tenuous atmospheres around these objects will be explored by examining how the light from the star varies as the KBO passes in front of it. This promises to be a completely new and powerful way of exploring the KBOs. We propose to continue to obtain very precise astrometry on the known brightest KBOs to determine more accurate orbits and thus reliable occultation predictions. In addition, we must also obtain accurate astrometry on faint field stars that the KBOs of interest may occult. On October 9, 2009 we predict KBO 55636 will occult a 13th magnitude star and this will be our first attempt to observe such an event.

  18. Tolerancing and design trades for free-flying occulters

    NASA Astrophysics Data System (ADS)

    Cady, E.

    2010-10-01

    Building free-flying occulters capable of detecting Earth-like planets requires precise optical design and tolerancing to suppress starlight by 10 orders of magnitude. Further, since the payload itself is acting as the optical element, this optical design must be developed in conjunction with the engineering of the underlying spacecraft. In this paper, we discuss the design of the occulter shape, the methods for placing tolerances on the optical system, and how these are iterated with thermal, structural, deployment and stationkeeping considerations. In particular, we discuss the relationship between occulter tolerancing and system parameters, such as occulter size and telescope diameter, and what design trades may be made to align the optical tolerances with the behavior of the physical occulter-telescope system.

  19. Radio occultation experiments with INAF-IRA radiotelescopes.

    NASA Astrophysics Data System (ADS)

    Pluchino, S.; Schillirò, F.; Salerno, E.; Pupillo, G.

    The Radio Occultation research program performed at the Medicina and Noto Radioastronomical Stations of the Istituto Nazionale di Astrofisica (INAF) - Istituto di Radioastronomia (IRA) includes observations of spacecraft by satellite and satellite by satellite events. The Lunar Radio Occultation (LRO) part of the program consists in collecting data of the lunar Total Electron Content (TEC), at different limb longitudes and at different time, in order to study long term variation of the Moon's ionosphere. The LRO program started at Medicina in September 2006 with the observation of the European probe SMART-1 during its impact on the lunar soil. It proceeded in 2007 with the observation of the lunar occultations of Saturn and Venus, and with the observation of Mars in 2008. On this occasion the probes Cassini, Venus Express, Mars Express, Mars Reconaissance Orbiter and Mars Odissey were respectively occulted by the moon. On Dec 1st 2008 a Venus lunar occultation occurred. On that occasion we performed the first Italian-VLBI (I-VLBI) tracking experiment by detecting the carrier signals coming from the Venus Express (VEX) spacecraft with both the IRA radiotelescopes together with the Matera antenna of the Italian Space Agency. The second part of the radio occultation program includes the observation of satellite by satellite occultation events, as well as mutual occultations of Jupiter satellites. These events are referred to as mutual phenomena (PHEMU). These observations are aimed to measure the radio flux variation during the occultation and to derive surface spatial characteristics such as Io's hot spots. In this work preliminary results of the Radio Occultation program will be presented.

  20. MRI Correlation of Radial Head Fractures and Forearm Injuries.

    PubMed

    Awan, Hisham; Goitz, Robert

    2017-03-01

    Background: Radial head fractures can be associated with soft tissue injuries of the forearm and wrist. The Essex-Lopresti injury can lead to significant morbidity, especially if the diagnosis is not made acutely. Better identification of such injuries is needed to allow optimal surgical treatment and prevent long-term sequelae. We used magnetic resonance imaging (MRI) to correlate the degree of soft tissue injuries with radial head fractures. Methods: Sixteen pairs of forearms with an associated radial head fracture in 15 patients prospectively underwent an MRI within 2 weeks of their injury. MRI findings were correlated with fracture type, associated soft tissue injury, and presence of symptomatic wrist pain. Results: According to the modified Mason classification, there were 8 type I, 5 type II, and 3 type III radial head fractures. Wrist pain was reported in 8 of 16 extremities, and 2 had associated wrist pathology, including an acute scaphoid fracture in 1 patient and a preexisting stage II scapholunate advanced collapse (SLAC) wrist in another patient. The MRI findings included an elbow effusion in all 16 patients, edema in the proximal third of the radius in 15 extremities, which extended to the middle third in 3 extremities, edema of the interosseous membrane (IOM) in 5 extremities, and edema of the soft tissues including the supinator and/or pronator quadratus in 13 extremities. Conclusions: Eighty percent of patients with edema of the IOM had associated wrist pain. Soft tissue injuries of the forearm did not correlate with the severity of the radial head fracture.

  1. Processing GPS Occultation Data To Characterize Atmosphere

    NASA Technical Reports Server (NTRS)

    Hajj, George; Kursinski, Emil; Leroy, Stephen; Lijima, Byron; de la Torre Juarez, Manuel; Romans, Larry; Ao, Chi

    2005-01-01

    GOAS [Global Positioning System (GPS) Occultation Analysis System] is a computer program that accepts signal-occultation data from GPS receivers aboard low-Earth-orbiting satellites and processes the data to characterize the terrestrial atmosphere and, in somewhat less comprehensive fashion, the ionosphere. GOAS is very robust and can be run in an unattended semi-operational processing mode. It features sophisticated retrieval algorithms that utilize the amplitudes and phases of the GPS signals. It incorporates a module that, using an assumed atmospheric refractivity profile, simulates the effects of the retrieval processing system, including the GPS receiver. GOAS utilizes the GIPSY software for precise determination of orbits as needed for calibration. The GOAS output for the Earth s troposphere and mid-to-lower stratosphere consists of high-resolution (<1 km) profiles of density, temperature, pressure, atmospheric refractivity, bending angles of signals, and water-vapor content versus altitude from the Earth s surface to an altitude of 30 km. The GOAS output for the ionosphere consists of electron-density profiles from an altitude of about 50 km to the altitude of a satellite, plus parameters related to the rapidly varying structure of the electron density, particularly in the E layer of the ionosphere.

  2. Halogen Occultation Experiment (HALOE) optical filter characterization

    NASA Technical Reports Server (NTRS)

    Harvey, Gale A.

    1989-01-01

    The Halogen Occultation Experiment (HALOE) is a solar occultation experiment that will fly on the Upper Atmosphere Research Satellite to measure mixing ratio profiles of O3, H2O, NO2, NO, CH4, HCl, and HF. The inversion of the HALOE data will be critically dependent on a detailed knowledge of eight optical filters. A filter characterization program was undertaken to measure in-band transmissions, out-of-band transmissions, in-band transmission shifts with temperature, reflectivities, and age stability. Fourier Transform Infrared Spectrometers were used to perform measurements over the spectral interval 400/cm to 6300/cm (25 micrometers to 1.6 micrometers). Very high precision (0.1 percent T) in-band measurements and very high resolution (0.0001 percent T) out-of-band measurements have been made. The measurements revealed several conventional leaks at 0.01 percent transmission and greatly enhanced (1,000) leaks to the 2-element filters when placed in a Fabry-Perot cavity. Filter throughput changes by 5 percent for a 25 C change in filter temperature.

  3. Saturn's shape from Cassini radio occultations

    NASA Astrophysics Data System (ADS)

    Flasar, F.; Schinder, P. J.; French, R. G.; Marouf, E. A.; Kliore, A. J.

    2013-12-01

    We report the shape of Saturn's isobaric surfaces between 0.1 mbar and ~1 bar determined from more than thirty Cassini radio-occultation soundings between 70 S and 60 N. The retrieval of pressure vs. planetary radius requires knowledge of the shape of the atmosphere. To do this, we use the gravitational coefficients given by Jacobson et al. (2006) and the angular velocities at the cloud-top level from the Voyager winds reported by Sanchez-Lavega et al. (2000). To keep the ray-tracing inversions tractable, we assume that the atmosphere is locally axisymmetric and that its angular velocity is a function of the distance from the planetary rotation axis; except for near the equator, the latter is equivalent to assuming that the winds are barotropic. Note that the "barotropic" assumption--which permits the use of a geopotential incorporating both gravity and differential rotation--need only apply in the atmospheric shell probed by the occultations. The retrieved isobaric surfaces show evidence of moderate baroclinicity. For example, the deviations of the 1-bar and 100-mbar surfaces from the geopotential surface assumed in the ray tracing are of order 10-20 km, less than a pressure scale height.

  4. Faster Processing for Inverting GPS Occultation Data

    NASA Technical Reports Server (NTRS)

    Ao, Chi

    2004-01-01

    A document outlines a computational method that can be incorporated into two prior methods used to invert Global Positioning System (GPS) occultation data [signal data acquired by a low-Earth-orbiting satellite as either this or the GPS satellite rises above or falls below the horizon] to obtain information on altitude-dependent properties of the atmosphere. The two prior inversion methods, known as back propagation and canonical transform, are computationally expensive because for each occultation, they involve numerical evaluation of a large number of diffraction-like spatial integrals. The present method involves an angular-spectrum-based phase-extrapolation approximation in which each data point is associated with a plane-wave component that propagates in a unique direction from the orbit of the receiving satellite to intersect a straight line tangent to the orbit at a nearby point. This approximation enables the use of fast Fourier transforms (FFTs), which apply only to data collected along a straight-line trajectory. The computation of the diffraction-like integrals in the angular-spectrum domain by use of FFTs takes only seconds, whereas previously, it took minutes.

  5. AKR occultation observed by KAGUYA (SELENE)

    NASA Astrophysics Data System (ADS)

    Hashimoto, K.; Kumamoto, A.; Kasahara, Y.; Ono, T.; Matsumoto, H.

    2008-12-01

    KAGUYA (SELENE) is a Japanese lunar orbiter launched on September 14, 2007. The Lunar Radar Sounder (LRS) is one of the scientific instruments on board KAGUYA. It consists of three subsystems: the sounder observation (SDR), the natural plasma wave receiver (NPW), and the wave form capture (WFC). The WFC measures two components of electric wave signals detected by the two orthogonal 30 m tip-to-tip antennas from 100Hz to 1MHz. WFC-H [1] observes plasma wave spectra in 1-1000kHz and AKR (auroral kilometric radiation) is often observed. Occultation of AKR occurs when the satellite goes behind the moon. Its frequency dependence and effects of the relative positions of the earth, the moon with the satellite will be evaluated. How the occultation is useful for the source estimation of AKR will be examined. Effects of a single rounded obstacle on diffraction [2] will also be examined. Background AKR emissions will be evaluated by Geotail observation if possible. Acknowledgments: The SELENE project has been organized by the Japan Aerospace Exploration Agency (JAXA). The authors express their thanks to all members of the SELENE project team. References [1] Y. Kasahara, Y. Goto, K. Hashimoto, T. Imachi, A. Kumamoto, T. Ono, and H. Matsumoto, Plasma Wave Observation Using Waveform Capture in the Lunar Radar Sounder on board the SELENE Spacecraft, Earth, Planets and Space, 60, 341-351, 2008. [2] Recommendation ITU-R P.526-8, Propagation by diffraction, ITU, 2003.

  6. A 2016 Ganymede stellar occultation event

    NASA Astrophysics Data System (ADS)

    D'Aversa, Emiliano; Oliva, Fabrizio; Sindoni, Giuseppe; Hinse, Tobias Cornelius; Plainaki, Christina; Aoki, Shohei; Person, Michael J.; Carlson, Robert W.; Orton, Glenn S.

    2017-04-01

    On 2016 April,13th the Jovian satellite Ganymede occulted a 7th magnitude star. The predicted occultation track crossed the Northern Pacific Ocean, Japan, and South Korea. Hence, it was a very favorable event due to the star brightness and to the visibility from the large aperture telescopes at Hawaii. While no other similar event is expected for the next 10 years, only two occultation events are reported in literature in the past, from Earth in 1972 [1] and from Voyager [2], in large disagreement in respect to the atmosphere detection. However, evidence of an exosphere around Ganymede was inferred by [3], through H Lyman alpha emission detected by Galileo UVS, and by [4], through HST/GHRS detection of far-UV atomic O airglow emissions, signature of dissociated molecular oxygen ([5],[6]). Later, the HST/STIS observations by [7] provided further evidence for exospheric neutral hydrogen. Since Ganymede is known to have an intrinsic magnetic field ([8]) reconnecting with the Jovian magnetic field and (partially) shielding the surface equatorial latitudes from the electron impact, the UV emissions have been so far attributed to auroral processes ([6]). Nevertheless, the physical mechanisms governing these processes are not known with certainty (e.g. whether the emissions morphology is determined by the spatial distribution of magnetospheric electrons or by an uneven O2 exosphere or both, see e.g.[9]). We took advantage of this event in order to search for a signature of Ganymede's exosphere in the occultation light curve, by using facilities on Mauna Kea at Hawaii (NASA-IRTF observatory) and at Sobaeksan Optical Astronomy Observatory (SOAO) in South Korea. At IRTF, both MORIS [10] and SpeX [11] instruments have been used, fed by the same optical entrance through a dichroic beam splitter at 0.95 micron. MORIS acquired a high-rate sequence of images about 0.25 sec apart in the visible range, while SpeX acquired a sequence of spectra at a bit lower rate, covering the 0

  7. [Atlas fractures].

    PubMed

    Schären, S; Jeanneret, B

    1999-05-01

    Fractures of the atlas account for 1-2% of all vertebral fractures. We divide atlas fractures into 5 groups: isolated fractures of the anterior arch of the atlas, isolated fractures of the posterior arch, combined fractures of the anterior and posterior arch (so-called Jefferson fractures), isolated fractures of the lateral mass and fractures of the transverse process. Isolated fractures of the anterior or posterior arch are benign and are treated conservatively with a soft collar until the neck pain has disappeared. Jefferson fractures are divided into stable and unstable fracture depending on the integrity of the transverse ligament. Stable Jefferson fractures are treated conservatively with good outcome while unstable Jefferson fractures are probably best treated operatively with a posterior atlanto-axial or occipito-axial stabilization and fusion. The authors preferred treatment modality is the immediate open reduction of the dislocated lateral masses combined with a stabilization in the reduced position using a transarticular screw fixation C1/C2 according to Magerl. This has the advantage of saving the atlanto-occipital joints and offering an immediate stability which makes immobilization in an halo or Minerva cast superfluous. In late instabilities C1/2 with incongruency of the lateral masses occurring after primary conservative treatment, an occipito-cervical fusion is indicated. Isolated fractures of the lateral masses are very rare and may, if the lateral mass is totally destroyed, be a reason for an occipito-cervical fusion. Fractures of the transverse processes may be the cause for a thrombosis of the vertebral artery. No treatment is necessary for the fracture itself.

  8. Molecular Mechanisms Underlying Occult Hepatitis B Virus Infection

    PubMed Central

    Samal, Jasmine; Kandpal, Manish

    2012-01-01

    Summary: Chronic hepatitis B virus (HBV) infection is a complex clinical entity frequently associated with cirrhosis and hepatocellular carcinoma (HCC). The persistence of HBV genomes in the absence of detectable surface antigenemia is termed occult HBV infection. Mutations in the surface gene rendering HBsAg undetectable by commercial assays and inhibition of HBV by suppression of viral replication and viral proteins represent two fundamentally different mechanisms that lead to occult HBV infections. The molecular mechanisms underlying occult HBV infections, including recently identified mechanisms associated with the suppression of HBV replication and inhibition of HBV proteins, are reviewed in detail. The availability of highly sensitive molecular methods has led to increased detection of occult HBV infections in various clinical settings. The clinical relevance of occult HBV infection and the utility of appropriate diagnostic methods to detect occult HBV infection are discussed. The need for specific guidelines on the diagnosis and management of occult HBV infection is being increasingly recognized; the aspects of mechanistic studies that warrant further investigation are discussed in the final section. PMID:22232374

  9. A Digital Video System for Observing and Recording Occultations

    NASA Astrophysics Data System (ADS)

    Barry, M. A. Tony; Gault, Dave; Pavlov, Hristo; Hanna, William; McEwan, Alistair; Filipović, Miroslav D.

    2015-09-01

    Stellar occultations by asteroids and outer solar system bodies can offer ground based observers with modest telescopes and camera equipment the opportunity to probe the shape, size, atmosphere, and attendant moons or rings of these distant objects. The essential requirements of the camera and recording equipment are: good quantum efficiency and low noise; minimal dead time between images; good horological faithfulness of the image timestamps; robustness of the recording to unexpected failure; and low cost. We describe an occultation observing and recording system which attempts to fulfil these requirements and compare the system with other reported camera and recorder systems. Five systems have been built, deployed, and tested over the past three years, and we report on three representative occultation observations: one being a 9 ± 1.5 s occultation of the trans-Neptunian object 28978 Ixion (m v =15.2) at 3 seconds per frame; one being a 1.51 ± 0.017 s occultation of Deimos, the 12 km diameter satellite of Mars, at 30 frames per second; and one being a 11.04 ± 0.4 s occultation, recorded at 7.5 frames per second, of the main belt asteroid 361 Havnia, representing a low magnitude drop (Δm v = ~0.4) occultation.

  10. Occult hepatitis B virus and hepatitis C virus infections.

    PubMed

    Carreño, Vicente; Bartolomé, Javier; Castillo, Inmaculada; Quiroga, Juan Antonio

    2008-01-01

    Occult HBV infection is a well-recognised clinical entity characterised by the detection of HBV-DNA in serum and/or in liver in the absence of detectable hepatitis B surface antigen (HBsAg). Occult HBV infection has been described not only in patients who have resolved an acute or chronic HBV infection but also in patients without any serological markers of a past HBV infection. Occult HBV infection in patients with chronic HCV infection may induce more severe liver disease and lower response rate to interferon treatment. The existence of occult HCV infections has been also reported more recently. Occult HCV infection is characterised by the presence of HCV-RNA in liver and peripheral blood mononuclear cells in the absence of detectable serum HCV-RNA. Occult HCV infection may occur under two different clinical situations: in hepatitis C antibody-(anti-HCV) negative and serum HCV-RNA-negative patients with abnormal liver function tests and in anti-HCV-positive patients who have no detectable serum HCV-RNA and who have normal liver enzymes. The clinical relevance of occult HCV infections is still under investigation. 2008 John Wiley & Sons, Ltd

  11. Satellite Occultation Measurements-Contributions to Middle Atmosphere Science

    NASA Astrophysics Data System (ADS)

    McCormick, M. P.; Chu, W. P.

    2003-12-01

    Solar occultation measurements from earth-orbit began with two orbits of data from aboard Apollo during the Apollo-Soyuz test project flight in 1975. The instrument was called SAM for the Stratospheric Aerosol Measurement. It was a simple proof-of-principle, one-spectral channel experiment that led to the long-duration occultation measurement series beginning in 1978 with the launch of SAM II aboard Nimbus 7. SAGE I, II, and III followed with increasing instrument complexity and capability. SAGE II and III are presently in orbit providing excellent high vertically-resolved measurements of aerosol, ozone, and other constituents. Other occultation sensors for long-duration measurements were launched in the 1990s including HALOE and POAM. This paper will present a historical overview of satellite occultation missions from 1975 to the present. The fundamentals of the occultation technique will be presented along with its advantages and comparison with other remote sensors. The occultation sensors, to-date, have produced exceedingly important measurements that have contributed to atmospheric and climate science. These have included such measurements as: the naming and characterization of Polar Stratospheric Clouds; aerosol and ozone associated with the wintertime polar vortex phenomena; ozone, HCl and HF trends associated with the effects of CFCs; the impact of volcanic aerosols; and aerosol and cirrus cloud distributions and trends. As the lead-off paper in this session, examples of the above data will be presented. Finally, some "lessons-learned" from these occultation missions will be discussed.

  12. Review: Occult hepatitis C virus infection: still remains a controversy.

    PubMed

    Vidimliski, Pavlina Dzekova; Nikolov, Igor; Geshkovska, Nadica Matevska; Dimovski, Aleksandar; Rostaing, Lionel; Sikole, Aleksandar

    2014-09-01

    Occult hepatitis C virus (HCV) infection is characterized by the presence of HCV RNA in the liver cells or peripheral blood mononuclear cells of the patients whose serum samples test negative for HCV RNA, with or without presence of HCV antibodies. The present study reviews the existing literature on the persistence of occult hepatitis C virus infection, with description of the clinical characteristics and methods for identification of occult hepatitis C. Occult hepatitis C virus infection was detected in patients with abnormal results of liver function tests of unknown origin, with HCV antibodies and HCV RNA negativity in serum, and also in patients with spontaneous or treatment-induced recovery from hepatitis C. The viral replication in the liver cells and/or peripheral blood mononuclear cells was present in all clinical presentations of occult hepatitis C. The peripheral blood mononuclear cells represent an extra-hepatic site of HCV replication. The reason why HCV RNA was not detectable in the serum of patients with occult hepatitis C, could be the low number of circulating viral particles not detectable by the diagnostic tests with low sensitivity. It is uncertain whether occult hepatitis C is a different clinical entity or just a form of chronic hepatitis C virus infection. Data accumulated over the last decade demonstrated that an effective approach to the diagnosis of HCV infection would be the implementation of more sensitive HCV RNA diagnostic assays, and also, examination of the presence of viral particles in the cells of the immune system.

  13. The mechanism of fracture

    SciTech Connect

    Goel, V.S.

    1986-01-01

    In this book eighty-five papers look at fractures. Topics covered are fracture mechanics, fracture mechanisms, evaluating fracture resistance, fracture toughness, predicting crack growth, surface cracking, crack initiation and propagation, weld fractures, engineering applications of fracture mechanics, fracture and failure in nonmetallic materials, dynamic fractures, test techniques, radiation embrittlement, applications of fracture mechanics, design concepts, and creep.

  14. The occultation of Kappa Geminorum by Eros. [stellar occultation observed for asteroid size and shape

    NASA Technical Reports Server (NTRS)

    Oleary, B.; Marsden, B. G.; Dragon, R.; Hauser, E.; Mcgrath, M.; Backus, P.; Robkoff, H.

    1976-01-01

    The paper discusses predictions and observations of the occultation of Kappa Gem by (433) Eros on January 24, 1975. Several positive and negative observations made in western New England are described. Local circumstances for the occultation are reconstructed, and the size and shape of Eros are determined analytically as well as graphically. The calculations yield two extremes for the cross section: a circle 23 km in diameter or a somewhat irregular figure 20 km by 6 or 7 km. Arguments based on the expected albedo of the asteroid suggest that the circle should be warped into an ellipse 21 by 13 km or that the irregular figure might be one component of a dumbbell-like profile.

  15. Facial fractures.

    PubMed Central

    Carr, M. M.; Freiberg, A.; Martin, R. D.

    1994-01-01

    Emergency room physicians frequently see facial fractures that can have serious consequences for patients if mismanaged. This article reviews the signs, symptoms, imaging techniques, and general modes of treatment of common facial fractures. It focuses on fractures of the mandible, zygomaticomaxillary region, orbital floor, and nose. Images p520-a p522-a PMID:8199509

  16. Stress Fractures

    MedlinePlus

    Stress fractures Overview Stress fractures are tiny cracks in a bone. They're caused by repetitive force, often from overuse — such as repeatedly jumping up and down or running long distances. Stress fractures can also arise from normal use of ...

  17. The Research and Education Collaborative Occultation Network: A System for Coordinated TNO Occultation Observations

    NASA Astrophysics Data System (ADS)

    Buie, Marc W.; Keller, John M.

    2016-03-01

    We describe a new system and method for collecting coordinated occultation observations of trans-Neptunian objects (TNOs). Occultations by objects in the outer solar system are more difficult to predict due to their large distance and limited span of the astrometric data used to determine their orbits and positions. This project brings together the research and educational community into a unique citizen-science partnership to overcome the difficulties of observing these distant objects. The goal of the project is to get sizes and shapes for TNOs with diameters larger than 100 km. As a result of the system design it will also serve as a probe for binary systems with spatial separations as small as contact systems. Traditional occultation efforts strive to get a prediction sufficiently good to place mobile ground stations in the shadow track. Our system takes a new approach of setting up a large number of fixed observing stations and letting the shadows come to the network. The nominal spacing of the stations is 50 km so that we ensure two chords at our limiting size. The spread of the network is roughly 2000 km along a roughly north-south line in the western United States. The network contains 56 stations that are committed to the project and we get additional ad hoc support from International Occultation Timing Association members. At our minimum size, two stations will record an event while the other stations will be probing the inner regions for secondary events. Larger objects will get more chords and will allow determination of shape profiles. The stations are almost exclusively sited and associated with schools, usually at the 9-12 grade level. We present a full description of the system we have developed for the continued exploration of the Kuiper Belt.

  18. Precise Astrometry for Predicting Kuiper Belt Object Occultations

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott; Person, Michael; Zuluaga, Carlos; Bosh, Amanda

    2011-08-01

    Occultations by Kuiper Belt objects remain elusive events, requiring precision astrometry for these faint bodies in the outer solar system. Monthly astrometry provides data that are crucial for our KBO ephemeris correction models, which then allow accurate shadow track predictions. Through the occultation events the diameters, possible companions and tenuous atmospheres around these objects will be explored by examining how the light from the star varies as the KBO passes in front of it. This promises to be a powerful way of exploring the KBOs. We propose to obtain very precise astrometry on 20 of the brightest known KBOs to determine more accurate orbits and thus reliable occultation predictions.

  19. Out of the blue finger ischaemia and occult colorectal cancer.

    PubMed

    Schattner, Ami

    2017-03-08

    A woman aged 66 years with a history of unprovoked deep venous thrombosis (DVT) presented with persistent digital ischaemic changes of 2 of her right hand fingers. Physical examination was otherwise normal and extensive laboratory and imaging studies were unremarkable. A history of unprovoked DVT and the current episode of digital ischaemia prompted concern for underlying occult malignancy. Repeated history-taking revealed a strongly positive family history suggesting an occult colorectal cancer. Colonoscopy with biopsy revealed adenocarcinoma. Adenocarcinoma of the colon has rarely been associated with paraneoplastic acral vascular syndrome. This report suggests that occult malignancy needs to be considered in patients with focal digital ischaemia as this association is poorly unrecognised.

  20. Occultations by Pluto and Charon - 1990-1999

    NASA Technical Reports Server (NTRS)

    Mink, Douglas J.; Klemola, Arnold R.; Buie, Marc W.

    1991-01-01

    The results of a photographic plate search for stars as faint as V = 16 which may be occulted by Pluto or Charon between January 1, 1990 and December 31, 1999 are presented. Circumstances for the closest approach of Pluto to 32 stars and Charon to 28 stars are presented. Photometric information is given for some of the brightest stars found in a search of the Space Telescope Guide Star Catalog for Pluto occultations. Finding charts from Space Telescope Guide Star plates are provided for some of the best events. The brightest star (V = 12.7) may be occulted by both Pluto and Charon on September 26, 1999.

  1. The clinical significance of occult HBV infection

    PubMed Central

    Squadrito, Giovanni; Spinella, Rosaria; Raimondo, Giovanni

    2014-01-01

    The presence of hepatitis B virus (HBV) DNA in HBV surface antigen (HBsAg)-negative individuals is defined as occult HBV infection (OBI). OBI is related in some cases to infection with variant viruses (S-escape mutants) undetectable by HBsAg commercial kits. More frequently, however, it is due to infection with wild-type viruses that are strongly suppressed in their replication activity. OBI may be involved in different clinical contexts, including the transmission of the infection by blood transfusion or liver transplantation and its acute reactivation when an immunosuppressive status occurs. Moreover, much evidence suggests that it may contribute to the development of cirrhosis and may have an important role in hepatocarcinogenesis. PMID:24714731

  2. Scaling An External Occulter Coronagraph Mission

    NASA Astrophysics Data System (ADS)

    Noecker, Martin C.

    2009-01-01

    An excellent candidate for the Terrestrial Planet Finder mission is an external occulter coronagraph like New Worlds Observer, in which the glare of the host star is blocked by an opaque starshade located between the star and the telescope which observes it. It has proven difficult to visualize and manage the interplay between starshade size and distance, telescope size, optical wavelength, and the depth of stellar suppression. The traditional method is to choose some parameters, calculate the stellar suppression, and iterate. This paper presents an alternate approach which exploits scaling relationships, allowing quick calculation of each new case and better visualization of the ramifications of a modest departure from that case. I apply this method to illustrate the pros and cons of a few different cases at different scales.

  3. Halogen occultation experiment intergrated test plan

    NASA Technical Reports Server (NTRS)

    Mauldin, L. E., III; Butterfield, A. J.

    1986-01-01

    The test program plan is presented for the Halogen Occultation Experiment (HALOE) instrument, which is being developed in-house at the Langley Research Center for the Upper Atmosphere Research Satellite (UARS). This comprehensive test program was developed to demonstrate that the HALOE instrument meets its performance requirements and maintains integrity through UARS flight environments. Each component, subsystem, and system level test is described in sufficient detail to allow development of the necessary test setups and test procedures. Additionally, the management system for implementing this test program is given. The HALOE instrument is a gas correlation radiometer that measures vertical distribution of eight upper atmospheric constituents: O3, HC1, HF, NO, CH4, H2O, NO2, and CO2.

  4. Pluto Stellar Occultation on 2008 Aug 25

    NASA Astrophysics Data System (ADS)

    Buie, Marc W.; Young, L. A.; Young, E. F.; Olkin, C. B.; Terrell, D.; Parker, J. W.; Durda, D.; Stansberry, J. A.; Reitsema, H.; French, R. G.; Shoemaker, K.; Brown, M. E.; Schaller, E. L.; Bauer, J. M.; Young, J. W.; Wasserman, L. H.; Pasachoff, J. M.; Lust, N.; Fernandez, Y. R.; Dellinger, J. A.; Garossino, P. G. A.; Grigsby, B.; Stone, R. P. S.; Dillon, W. G.; Mezzalira, F.; Ryan, E. V.; Ryan, W.; Souza, S. P.; Williams, R.; Sexton, C.

    2009-01-01

    We report on a successful occultation of a star by Pluto that was observable over much of the south and western United States. The centerline was close to WIRO. We will present seven complete lightcurves from Crossley/Lick, WIRO, SBO/CU, Palomar, JPL/TMO, Sierra Stars Obs., and Magdalena Ridge Observatory. We have 2 partial lightcurves from Lowell Obs. and McDonald Obs. where data loss was caused by clouds. There were attempts at the Steward 90", George Observatory, and New Mexico Skies that were clouded out. The UCF station near Orlando was clearly an appulse. A number of other amateurs also succeeded in collecting data. Our presentation will provide a final geometric solution for the event as well as baseline fits to the atmospheric structure. This work was supported by NASA Planetary Astronomy grants NNX08AO626 and NNX08AO50G.

  5. What can the occult do for you?

    NASA Astrophysics Data System (ADS)

    Holwerda, B. W.; Keel, W. C.

    2017-03-01

    Interstellar dust is still a dominant uncertainty in Astronomy, limiting precision in e.g., cosmological distance estimates and models of how light is re-processed within a galaxy. When a foreground galaxy serendipitously overlaps a more distant one, the latter backlights the dusty structures in the nearer foreground galaxy. Such an overlapping or occulting galaxy pair can be used to measure the distribution of dust in the closest galaxy with great accuracy. The STARSMOG program uses Hubble to map the distribution of dust in foreground galaxies in fine (<100 pc) detail. Integral Field Unit (IFU) observations will map the effective extinction curve, disentangling the role of fine-scale geometry and grain composition on the path of light through a galaxy. The overlapping galaxy technique promises to deliver a clear understanding of the dust in galaxies: geometry, a probability function of dimming as a function of galaxy mass and radius, and its dependence on wavelength.

  6. Rib Fracture Patterns and Radiologic Detection – A Restraint-Based Comparison

    PubMed Central

    Crandall, Jeff; Kent, Richard; Patrie, James; Fertile, Jay; Martin, Peter

    2000-01-01

    This paper presents a study of the rib fracture patterns generated in simulated frontal collisions and the visibility of the rib fractures on plain film radiographs. Using 29 cadaver subjects, rib fractures were identified on oblique, lateral, and anteroposterior chest films by five radiologists independently and were compared with fractures found during a detailed necropsy. Physical, geometric, and experimental factors demonstrated an influence on the ability of a radiologist to identify rib fractures on an x-ray. Specifically, the restraint system configuration, the total number of fractures, the circumferential location of the fracture, the rib number, and the aspect (right or left) affected fracture identification. The results verify that torso belt loading produces rib fractures generally located along the path of the belt whereas superimposed airbag loading results in a more distributed and posterolateral fracture pattern. A higher proportion of rib fractures was identified on x-ray for occupants restrained by only a belt (44% of fractures) than for occupants restrained by both a belt and an airbag (24% of fractures). Overall, less than 40% of the rib fractures were detected upon an initial examination of radiographs. After being provided with the location of all fractures, detection increased to 49%. On average, occult rib fractures resulted in an average underreporting of injury severity of more than one AIS level. PMID:11558086

  7. Pluto's Lower Atmosphere from Stellar Occultations

    NASA Astrophysics Data System (ADS)

    Young, Leslie; Buie, M. W.; Olkin, C. B.; Young, E. F.; French, R. G.; Howell, R. R.

    2008-09-01

    Ever since the Pluto occultation of 1988, the nature of Pluto's lower atmosphere has been a mystery: the lightcurve shows a difference between the upper and lower atmosphere, but it has been unclear whether this is due to hazes, a steep thermal gradient, or a combination of the two (Elliot & Young, 1992 AJ 103, 991; Hubbard et al. 1990, Icarus, 84, 1) Recent high-quality lightcurves allow us to place limits on the haze in Pluto's atmosphere. Especially important is the dual-wavelength (0.5 and 0.8 micron) occultation observed from Mount John Observatory in New Zealand on 2007 July 31. This site was 60 ± 4 km from the central track of the shadow, and the lightcurves clearly show a central flash, or a brightening due to strong lateral refocusing and the convergence of multiple images around the limb of an elliptical atmosphere. These lightcurves constrain the structure of the lower atmosphere in three ways. First, the surface-grazing ray must have a large enough bending angle to reach the center of the shadow. Second, haze of sufficient optical depth to affect the main drop in the lightcurve will also decrease the height of the central flash. The height and location of the central flash can be well modeled with a clear atmosphere. Third, hazes of the size expected at Pluto will have a wavelength-dependent absorption, but the red and blue channels of the Mount John lightcurves show no variation with wavelength. We will discuss limits on the hazes, and place these limits in the context of Triton hazes, heating by dust, and New Horizons detection limits.

  8. A game of two discs: a case of non-contiguous and occult cervical spine injury in a rugby player

    PubMed Central

    O'Sullivan, Michael D.; Piggot, Robert; Jaddan, Mutaz; McCabe, John P.

    2016-01-01

    The aim of this case report was to highlight the application of magnetic resonance imaging (MRI) in elucidating serious and occult injuries in a single case of hyperflextion injury of a patient cervical spine (C-Spine). A chart and radiology review was performed to establish the sequence of care and how the results of imaging studies influenced the clinical management in this trauma case. Plain radiographs and computed tomography (CT) imaging modalities of the C-Spine revealed bilateral C4/C5 facetal subluxation with no obvious fractures; however, the MR imaging of the C-Spine revealed a non-contiguous and occult injury to C6/C7 disc with a posterior annular tear and associated disc extrusion. This altered the operative intervention that was initially planned. MR imaging proved an invaluable diagnostic addition in this particular case of cervical trauma in a rugby player following a hyperflextion injury, by revealing a serious non-contiguous and occult injury of the C-Spine. PMID:26980714

  9. Occultations of stars by solar system objects. V - A photographic search for occultations by selected asteroids in 1984

    NASA Technical Reports Server (NTRS)

    Millis, R. L.; Wasserman, L. H.; Franz, O. G.; Bowell, E.; Klemola, A.

    1984-01-01

    Photographic plates taken with the 0.5-m Carnegie double astrograph have been used to identify upcoming asteroid occultations not found in earlier star catalog searches. Twenty-six occultations involving the minor planets 1 Ceres, 10 Hygiea, 52 Europa, 65 Cybele, 451 Patientia, 511 Davida, and 704 Interamnia were found in this search. Of particular interest is the occultation of BD + 8 deg 471 by 1 Ceres on November 13, 1984, which is predicted to be observable throughout much of Mexico and, perhaps, in the southern United States.

  10. Clinical Utility of Chest Computed Tomography in Patients with Rib Fractures CT Chest and Rib Fractures.

    PubMed

    Chapman, Brandon C; Overbey, Douglas M; Tesfalidet, Feven; Schramm, Kristofer; Stovall, Robert T; French, Andrew; Johnson, Jeffrey L; Burlew, Clay C; Barnett, Carlton; Moore, Ernest E; Pieracci, Fredric M

    2016-12-01

    Chest CT is more sensitive than a chest X-ray (CXR) in diagnosing rib fractures; however, the clinical significance of these fractures remains unclear. The purpose of this study was to determine the added diagnostic use of chest CT performed after CXR in patients with either known or suspected rib fractures secondary to blunt trauma. Retrospective cohort study of blunt trauma patients with rib fractures at a level I trauma center that had both a CXR and a CT chest. The CT finding of ≥ 3 additional fractures in patients with ≤ 3 rib fractures on CXR was considered clinically meaningful. Student's t-test and chi-square analysis were used for comparison. We identified 499 patients with rib fractures: 93 (18.6%) had CXR only, 7 (1.4%) had chest CT only, and 399 (79.9%) had both CXR and chest CT. Among these 399 patients, a total of 1,969 rib fractures were identified: 1,467 (74.5%) were missed by CXR. The median number of additional fractures identified by CT was 3 (range, 4 - 15). Of 212 (53.1%) patients with a clinically meaningful increase in the number of fractures, 68 patients underwent one or more clinical interventions: 36 SICU admissions, 20 pain catheter placements, 23 epidural placements, and 3 SSRF. Additionally, 70 patients had a chest tube placed for retained hemothorax or occult pneumothorax. Overall, 138 patients (34.5%) had a change in clinical management based upon CT chest. The chest X-ray missed ~75% of rib fractures seen on chest CT. Although patients with a clinical meaningful increase in the number of rib fractures were more likely to be admitted to the intensive care unit, there was no associated improvement in pulmonary outcomes.

  11. Clinical Utility of Chest Computed Tomography in Patients with Rib Fractures CT Chest and Rib Fractures

    PubMed Central

    Chapman, Brandon C.; Overbey, Douglas M.; Tesfalidet, Feven; Schramm, Kristofer; Stovall, Robert T.; French, Andrew; Johnson, Jeffrey L.; Burlew, Clay C.; Barnett, Carlton; Moore, Ernest E.; Pieracci, Fredric M.

    2016-01-01

    Background Chest CT is more sensitive than a chest X-ray (CXR) in diagnosing rib fractures; however, the clinical significance of these fractures remains unclear. Objectives The purpose of this study was to determine the added diagnostic use of chest CT performed after CXR in patients with either known or suspected rib fractures secondary to blunt trauma. Methods Retrospective cohort study of blunt trauma patients with rib fractures at a level I trauma center that had both a CXR and a CT chest. The CT finding of ≥ 3 additional fractures in patients with ≤ 3 rib fractures on CXR was considered clinically meaningful. Student’s t-test and chi-square analysis were used for comparison. Results We identified 499 patients with rib fractures: 93 (18.6%) had CXR only, 7 (1.4%) had chest CT only, and 399 (79.9%) had both CXR and chest CT. Among these 399 patients, a total of 1,969 rib fractures were identified: 1,467 (74.5%) were missed by CXR. The median number of additional fractures identified by CT was 3 (range, 4 - 15). Of 212 (53.1%) patients with a clinically meaningful increase in the number of fractures, 68 patients underwent one or more clinical interventions: 36 SICU admissions, 20 pain catheter placements, 23 epidural placements, and 3 SSRF. Additionally, 70 patients had a chest tube placed for retained hemothorax or occult pneumothorax. Overall, 138 patients (34.5%) had a change in clinical management based upon CT chest. Conclusions The chest X-ray missed ~75% of rib fractures seen on chest CT. Although patients with a clinical meaningful increase in the number of rib fractures were more likely to be admitted to the intensive care unit, there was no associated improvement in pulmonary outcomes. PMID:28144607

  12. Comparative study on the clinical and virological characteristics among patients with single occult hepatitis B virus (HBV), single occult hepatitis C virus (HCV) and occult HBV and HCV dual infection.

    PubMed

    Castillo, Inmaculada; Rodríguez-Iñigo, Elena; López-Alcorocho, Juan Manuel; Bartolomé, Javier; Pardo, Margarita; Carreño, Vicente

    2007-03-01

    Occult hepatitis B virus (HBV) and occult hepatitis C virus (HCV) infection are two recently described different forms of HBV and HCV infections. This work compares the clinical, virologic, and histologic characteristics of patients with occult dual infection to those of patients with single occult HBV or HCV infection. Seventy-six patients with abnormal liver function tests of unknown etiology (serum HBsAg, anti-HCV, HBV-DNA, and HCV-RNA negative) were included in the study. Viral genomes were tested in liver by real-time PCR and confirmed by in situ hybridization. Of the 76 patients, 17 had occult HBV infection (intrahepatic HBV-DNA positive, HCV-RNA negative), 35 had occult HCV infection (intrahepatic HCV-RNA positive, HBV-DNA negative) and 24 occult dual infection (intrahepatic HCV-RNA and HBV-DNA). No differences among the three groups were found regarding clinical and epidemiologic data. The median load of intrahepatic genomic and antigenomic HCV-RNA strands was similar between single occult HCV infection and occult HBV and HCV dual infection. The percentage of HCV-infected hepatocytes did not differ between these groups. In occult single HBV infection, intrahepatic levels of HBV-DNA and percentage of HBV-infected hepatocytes were similar to the group of patients with occult dual infection. Finally, no differences were found in histological liver damage among the three groups. In conclusion, liver disease in patients with occult dual infection was not more severe than in patients with single occult HBV or occult HCV infection. Moreover, in occult dual infection there is no a reciprocal inhibition of the viral genomes.

  13. Precise Astrometry for Predicting Kuiper Belt Object Occultations

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott; Elliot, James; Kern, Susan; Zuluaga, Carlos; Gulbis, Amanda

    2008-08-01

    In order to observe an occultation of a bright star by a Kuiper Belt object the event must first be predicted as to where and when it will happen. These predictions require precise astrometry every few months of the largest Kuiper Belt objects. Through the occultation events the diameters, possible companions and possible tenuous atmospheres around these objects will be explored by examining how the light from the star varies as the KBO passes in front of it. This promises to be a completely new and powerful way of exploring the KBOs. We propose to continue to obtain very precise astrometry on the known brightest KBOs to determine more accurate orbits and thus reliable occultation predictions. In addition, we must also obtain accurate astrometry on faint field stars that the KBOs of interest may occult.

  14. Precise Astrometry for Predicting Kuiper Belt Object Occultations

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott; Person, Michael; Zuluaga, Carlos; Bosh, Amanda

    2012-08-01

    Occultations by Kuiper Belt objects remain elusive events, requiring precision astrometry for these faint bodies in the outer solar system. Routine astrometry provides data that are crucial for our KBO ephemeris correction models, which then allow accurate shadow track predictions. Through the occultation events the diameters, possible companions and tenuous atmospheres around these objects will be explored by examining how the light from the star varies as the KBO passes in front of it. This is a powerful way to determine the physical characteristics of the KBOs. We propose to obtain very precise astrometry on 20 of the brightest known KBOs to determine more accurate orbits and thus reliable occultation predictions. We also require telescope time to obtain precise astrometry on possible stars that will be occulted by a KBO in the future.

  15. Precise Astrometry for Predicting Kuiper Belt Object Occultations

    NASA Astrophysics Data System (ADS)

    Sheppard, Scott; Person, Michael; Zuluaga, Carlos; Bosh, Amanda

    2013-02-01

    Occultations by Kuiper Belt objects remain elusive events, requiring precision astrometry for these faint bodies in the outer solar system. Routine astrometry provides data that are crucial for our KBO ephemeris correction models, which then allow accurate shadow track predictions. Through the occultation events the diameters, possible companions and tenuous atmospheres around these objects will be explored by examining how the light from the star varies as the KBO passes in front of it. This is a powerful way to determine the physical characteristics of the KBOs. We propose to obtain very precise astrometry on 10 of the brightest known KBOs to determine more accurate orbits and thus reliable occultation predictions. We also require telescope time to obtain precise astrometry on possible stars that will be occulted by a KBO in the future.

  16. Characterization and evolution of distant planetary atmospheres using stellar occultations

    NASA Astrophysics Data System (ADS)

    Young, L. A.

    2008-09-01

    Ground-based or near-Earth (e.g., HST) stellar occultations of every atmosphere in our solar system has been observed: Venus, Mars, Jupiter, Saturn, Titan, Uranus, Neptune, Triton, and Pluto [1]. These observations probe the atmospheres at roughly 0.1 to 100 microbar. I will talk about three aspects of stellar occultations: one-dimensional vertical profiles of the atmosphere, two- or three-dimensional atmospheric states, and the time evolution of atmosphere. In all three, I will draw on recent observations, with an emphasis on Pluto. Occultations are particularly important for the study of Pluto's atmosphere, which is impossible to study with imaging, and extremely difficult to study with spectroscopy. It was discovered by stellar occultation in 1988 [2]. No subsequent Pluto occultations were observed until two events in 2002 [3]. Pluto is now crossing the galactic plane, and there have been several additional occultations observed since 2006. These include a high signal-to-noise observation from the Anglo Australian Observatory in 2006 [4] (Fig 1), densely spaced visible and infrared observations of Pluto's upper atmosphere from telescopes in the US and Mexico in March, 2007 [5] (Fig. 2), and a dualwavelength central flash observation from Mt. John in July, 2007 [6] (Fig 3). The flux from a star occulted by an atmosphere diminishes primarily due to the increase in refraction with depth in the atmosphere, defocusing the starlight, although absorption and tangential focusing can also contribute. Because the atmospheric density, to first order, follows an exponential, it is feasible to derive a characteristic pressure and temperature from isothermal fits to even low-quality occultation light curves. Higher quality light curves allow fits with more flexible models, or light curve inversions that derive temperatures limited by the resolution of the data. These allow the derivation of one-dimensional profiles of temperature and pressure vs. altitude, which are critical

  17. The Mariner Jupiter/Saturn ring occultation experiment

    NASA Technical Reports Server (NTRS)

    Eshleman, V. R.

    1974-01-01

    Radio occultation measurements of Saturn's rings as measured by the Mariner Jupiter/Saturn radio science experiment are reported. These signal measurements provide information on size, distribution, and density of particle material found in the rings.

  18. Monochromatic verification of high-contrast imaging with an occulter.

    PubMed

    Sirbu, Dan; Kasdin, N Jeremy; Vanderbei, Robert J

    2013-12-30

    One of the most promising concepts of starlight suppression for direct imaging of exoplanets is flying a specially-shaped external occulter in formation with a space telescope. Here we present contrast performance verification of an occulter design scaled to laboratory-size using Fresnel numbers corresponding to the space design. Experimental design innovations include usage of an expanding beam to minimize phase aberrations, and an outer ring to minimize hard-edge diffraction effects. The apodizing performance of the optimized occulter edge is compared with a baseline case of a circular occulter and shown to result in contrast improvements. Experimental results in red monochromatic light show that the achieved laboratory contrast exceeds ten orders of magnitude, but with differences from the theoretical diffraction analysis limited by specular reflection from the mask edges.

  19. Radio occultation based on BeiDou satellite navigation

    NASA Astrophysics Data System (ADS)

    Jiang, Hu; Hu, Haiying; Shen, Xue-min; Gong, Wenbin; Zhang, Yonghe

    2014-11-01

    With the development of GNSS systems, it has become a tendency that radio occultation is used to sense the Earth's atmosphere. By this means, the moisture, temperature, pressure, and total electron content can be derived. Based on the sensing results, more complicated models for atmosphere might come into being. Meteorology well benefits from this technology. As scheduled, the BD satellite navigation system will have a worldwide coverage by the end of 2020. Radio occultation studies in China have been highlighted in the recent decade. More and more feasibilities reports have been published in either domestic or international journals. Herein, some scenarios are proposed to assess the coverage of radio occultation based on two different phases of BD satellite navigation system. Phase one for BD is composed of GEO,IGSO and several MEO satellites. Phase two for BD consists mostly of 24 MEO satellites, some GEO and IGSO satellites. The characteristics of radio occultation based on these two phases are presented respectively.

  20. Nondimensional Representations for Occulter Design and Performance Evaluation

    NASA Technical Reports Server (NTRS)

    Cady, Eric

    2011-01-01

    An occulter is a spacecraft with a precisely-shaped optical edges which ies in formation with a telescope, blocking light from a star while leaving light from nearby planets una ected. Using linear optimization, occulters can be designed for use with telescopes over a wide range of telescope aperture sizes, science bands, and starlight suppression levels. It can be shown that this optimization depends primarily on a small number of independent nondimensional parameters, which correspond to Fresnel numbers and physical scales and enter the optimization only as constraints. We show how these can be used to span the parameter space of possible optimized occulters; this data set can then be mined to determine occulter sizes for various mission scenarios and sets of engineering constraints.

  1. Digital Tomosynthesis to Evaluate Fracture Healing: Prospective Comparison With Radiography and CT.

    PubMed

    Ha, Alice S; Lee, Amie Y; Hippe, Daniel S; Chou, Shinn-Huey S; Chew, Felix S

    2015-07-01

    Radiography, currently the standard for postoperative fracture imaging, is limited by overlapping bone and hardware. Tomosynthesis has the benefit of level-by-level imaging without the disadvantages of metal artifacts, increased radiation, and higher costs of CT, the current problem-solving tool. The purpose of this study was to compare tomosynthesis with radiography for evaluating fracture healing. In a prospective study, patients within 1 year of wrist hardware fixation underwent radiography, tomosynthesis, and CT, and the images were interpreted by three readers. The diagnostic accuracy of radiology and tomosynthesis was assessed with ROC curves, and interreader agreement was assessed with Cohen kappa. Fracture scores were correlated with Disabilities of the Arm, Shoulder, and Hand (DASH) and pain scores. The study participants were 49 patients with 51 fractures. The most common fracture sites were distal radius (43%), scaphoid (18%), and metacarpals (18%). Rates of cortex obscuration by hardware were 2% for CT, 8% for tomosynthesis, and 15% for radiography (p < 0.01 between one modality and another). Detection of cortical fracture lines was significantly better with tomosynthesis than with radiography (AUC, 0.84 vs 0.76, p = 0.01). Inter-reader agreement was moderate for both radiography and tomosynthesis (κ = 0.44 vs 0.55, p = 0.051). There was no significant correlation between fracture scores and DASH scores. There was significant correlation between reported pain levels and both tomosynthesis (r = 0.28, p = 0.03) and CT (r = 0.29, p = 0.04) fracture scores. Tomosynthesis provides diagnostic information superior to that of ra diography in postoperative evaluation of wrist fractures with lower cost and radiation than CT and should be considered in fracture follow-up imaging of other bones.

  2. The shape of Mars from the Mariner 9 occultations.

    NASA Technical Reports Server (NTRS)

    Cain, D. L.; Kliore, A. J.; Seidel, B. L.; Sykes, M. J.

    1972-01-01

    The extinction time of the radio signal, as the Mariner 9 spacecraft was occultated by Mars, together with an accurate ephemeris of the spacecraft were used to determine radii from the mass center to the occulting feature. Similarly estimations were made of the radius to a point where the pressure reached a certain fixed value. Several simple models were proposed to fit both sets of radii data.

  3. The rings of Uranus - Occultation profiles from three observatories

    NASA Technical Reports Server (NTRS)

    Elias, J. H.; Frogel, J. A.; French, R. G.; Matthews, K.; Meech, K. J.; Mink, D. J.; Nicholson, P. D.; Sicardy, B.; Liller, W.; Elliot, J. L.

    1983-01-01

    Occultation profiles for the nine confirmed Uranian rings obtained from Las Campanas, the European Southern Observatory, and Cerro Tololo on 15-16 August 1980 are compared. The alpha ring shows a 'double-dip' structure; the eta ring shows a broad and narrow component (similar to Saturn's F ring); and the epsilon ring shows six features that appear in the data from all three observatories. Diffraction fringes appear at the edges of several of the occultation profiles.

  4. First Results From The Taiwanese-American Occultation Survey (TAOS)

    SciTech Connect

    Zhang, Z; Bianco, F B; Lehner, M J; Coehlo, N K; Wang, J; Mondal, S; Alcock, C; Axelrod, T; Byun, Y; Chen, W P; Cook, K H; Dave, R; de Pater, I; Porrata, R; Kim, D; King, S; Lee, T; Lin, H; Lissauer, J J; Marshall, S L; Protopapas, P; Rice, J A; Schwamb, M E; Wang, S; Wen, C

    2008-08-22

    Results from the first two years of data from the Taiwanese-American Occultation Survey (TAOS) are presented. Stars have been monitored photometrically at 4 Hz or 5 Hz to search for occultations by small ({approx}3 km) Kuiper Belt Objects (KBOs). No statistically significant events were found, allowing us to present an upper bound to the size distribution of KBOs with diameters 0.5 km < D < 28 km.

  5. Occulter Based Missions of Different Scales for Terrestrial Planet Imaging

    NASA Astrophysics Data System (ADS)

    Kasdin, N. J.; Spergel, D. N.; Vanderbei, R.; Shaklan, S.; Lisman, D. P.; Savransky, D.; Cady, E.; Soummer, R.

    2010-10-01

    Free flying occulters are an attractive option as a space mission architecture for imaging exosolar planets, particular ones in the habitable zone. Their appeal is two-fold: the inner working angle is largely decoupled from telescope diameter and, because they suppress starlight before entering the telescope, there is no need for wavefront control. We present the basic operating principles of occulters for high-contrast, including preliminary stationkeeping simulations, and a manufacturing approach being studied as part of NASA's Technology Demonstration for Exoplanet Missions. Our main focus is a comparison of mission architectures employing occulters at varying scales: large flagship observatories (THEIA, NWO), existing large aperture telescopes (JWST), small dedicated telescopes (O3), and small general purpose telescopes (such as a dark energy mission like EUCLID). THEIA, the Telescope for Habitable Exoplanets and Interstellar/Intergalactic Astronomy, is a multi-instrument space-telescope concept employing a 4-m diffraction-limited telescope operating at UV and Visible wavelengths that was developed as part of NASAs Astrophysics Strategic Mission Concept Studies in 2009 and presented to the US Academy's decadal survey review, Astro2010. By combining the telescope with a roughly 40 m occulter, operating at two different telescope-occulter separations, planets as small as Earth can be characterized over a broad band, including R>70 spectra. O3, the Occulting Ozone Observatory, is a smaller mission costing less than 1B that uses a 1 to 2 m telescope combined with a roughly 30 m occulter. O3 is capable of time-resolved photometry over 8 bands, focusing on biomarkers, such as detecting the strong ozone feature, and surface characterization. It also provides the capability for enough repeat visits to support orbit determination. We will compare the science yield and architecture and how different coronagraph and occulter approaches perform at these different mission

  6. A comparison of the rates of union after cancellous iliac crest bone graft and Kirschner-wire fixation in the treatment of stable and unstable scaphoid nonunion.

    PubMed

    Park, H Y; Yoon, J O; Jeon, I H; Chung, H W; Kim, J S

    2013-06-01

    This study was performed to determine whether pure cancellous bone graft and Kirschner (K-) wire fixation were sufficient to achieve bony union and restore alignment in scaphoid nonunion. A total of 65 patients who underwent cancellous bone graft and K-wire fixation were included in this study. The series included 61 men and four women with a mean age of 34 years (15 to 72) and mean delay to surgery of 28.7 months (3 to 240). The patients were divided into an unstable group (A) and stable group (B) depending on the pre-operative radiographs. Unstable nonunion was defined as a lateral intrascaphoid angle > 45°, or a radiolunate angle > 10°. There were 34 cases in group A and 31 cases in group B. Bony union was achieved in 30 patients (88.2%) in group A, and in 26 (83.9%) in group B (p = 0.439). Comparison of the post-operative radiographs between the two groups showed no significant differences in lateral intrascaphoid angle (p = 0.657) and scaphoid length (p = 0.670) and height (p = 0.193). The radiolunate angle was significantly different (p = 0.020) but the mean value in both groups was < 10°. Comparison of the dorsiflexion and palmar flexion of movement of the wrist and the mean Mayo wrist score at the final clinical visit in each group showed no significant difference (p = 0.190, p = 0.587 and p = 0.265, respectively). Cancellous bone graft and K-wire fixation were effective in the treatment of stable and unstable scaphoid nonunion.

  7. Brachial Artery Transection After a Closed Traumatic Isolated Medial Epicondyle Fracture in a Pediatric Patient: A Case Report.

    PubMed

    Schwartz, Brandon S; Paryavi, Ebrahim; Eglseder, W Andrew; Pensy, Raymond A; Abzug, Joshua M

    2017-09-01

    Medial epicondyle fractures in pediatric patients might be associated with an occult elbow dislocation and neurovascular damage. A single case of a medial epicondyle fracture presenting with brachial artery transection was reviewed. Presentation, clinical course, and early outcome are reported. A 14-year-old patient presenting with an apparently isolated medial epicondyle fracture was found to have examination and diagnostic test findings consistent with brachial artery transection. His injury was explored and repaired acutely, resulting in acute return of perfusion. Final follow-up revealed 0° to 130° of flexion-extension arc of motion and full pronation and supination with normal sensory and motor function of the hand. Pediatric medial epicondyle fractures should alert the clinician to the possibility of an occult dislocation of the elbow, and a full neurovascular assessment should be performed. Early recognition and repair of a vascular injury associated with this fracture can lead to a good outcome.

  8. Earth Occultation Monitoring with the Fermi Gamma Ray Burst Monitor

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, Colleen A.

    2014-01-01

    Using the Gamma Ray Burst Monitor (GBM) on-board Fermi, we are monitoring the hard X-ray/soft gamma ray sky using the Earth occultation technique (EOT). Each time a source in our catalog is occulted by (or exits occultation by) the Earth, we measure its flux using the change in count rates due to the occultation. Currently we are using CTIME data with 8 energy channels spanning 8 keV to 1 MeV for the GBM NaI detectors for daily monitoring. Light curves, updated daily, are available on our website http://heastro.phys.lsu.edu/gbm. Our software is also capable of performing the Earth occultation monitoring using up to 128 energy bands, or any combination of those bands, using our 128-channel, 4-s CSPEC data. The GBM BGO detectors, sensitive from about 200 keV to 40 keV, can also be used with this technique. In our standard application of the EOT, we use a catalog of sources to drive the measurements. To ensure that our catalog is complete, our team has developed an Earth occultation imaging method. In this talk, I will describe both techniques and the current data products available. I will highlight recent and important results from the GBM EOT, including the current status of our observations of hard X-ray variations in the Crab Nebula.

  9. Possible occultation by Pluto from US East Coast

    NASA Astrophysics Data System (ADS)

    Waagen, Elizabeth O.

    2012-06-01

    We have been asked to help disseminate the news of a possible occultation by Pluto visible to observers on the US East coast. Although the AAVSO does not ordinarily issue announcements of upcoming occultations, in this case the object is Pluto and the NASA New Horizons mission (http://www.nasa.gov/mission_pages/newhorizons/main/index.html) will be visiting Pluto in 2015. The information below has been supplied by Dr. Leslie Young (Southwest Research Institute), who is coordinating this observing campaign on Pluto. Dr. Young is also Deputy Project Scientist for the New Horizons mission. ALERT: Possible Pluto occultation Wednesday night (2012/06/14 03:28 UT) from US East coast. CONTACT: Leslie Young (layoung@boulder.swri.edu; work: 303-546-6057; skype: drpluto). Also see our planning pages in progress at http://wiki.boulder.swri.edu/mediawiki/index.php/2012-06-14_Pluto_occultation. Pluto's thin, nitrogen atmosphere is in vapor-pressure equilibrium with the surface ice, and changes seasonally. We've seen it double since 1988, and now we measure its pressure once or twice a year. The technique we use is stellar occultation, when a star passes behind Pluto's atmosphere. The atmosphere defocuses the starlight. By the timing of the fading of the star, we measure the pressure and temperature in Pluto's atmosphere at ~10 km resolution. MORE INFORMATION: See http://wiki.boulder.swri.edu/mediawiki/index.php/2012-06-14_Pluto_occultation.

  10. Image Analysis of The 2012 Pluto (Near) Occultation

    NASA Astrophysics Data System (ADS)

    Knox, K.

    2013-09-01

    Imagery was gathered at the AMOS observatory on the 3.6-meter telescope for the expected occultation of a star by the dwarf planet, Pluto, on 29 June 2012. The imagery was taken at 5 Hz for 40 minutes before and after the expected time of occultation. The initial analysis of the photometry indicated that Pluto did not occult the star. This conclusion could not be determined from a simple visual inspection of the imagery. Understanding why and by how much Pluto missed occulting the star can aid in predicting future occultations. To analyze the imagery, a least squares method was developed to measure the closest approach, in arc seconds. The method is based on averaging the modulus squared of the Fourier transform of the imagery. This is similar to Labeyrie's technique in speckle interferometry. From this method, fringes were detected and measured as a function of time over the period before and after the near occultation. The analysis showed that Pluto missed the star by 0.135 arcsec with an accuracy of 0.0025 arcsec. The use of over 24,000 image frames leads to this high level of precision. In addition, Labeyrie's technique applied to the images of Pluto by itself shows that Pluto and its moon, Charon, were oriented perpendicularly to the direction of travel, making it even less likely that Pluto would overlap with the star. This talk will describe the methods developed to conduct this analysis and how the conclusions were reached.

  11. Occult hepatitis C virus infection among hemodialysis patients.

    PubMed

    Barril, Guillermina; Castillo, Inmaculada; Arenas, María Dolores; Espinosa, Mario; Garcia-Valdecasas, Juan; Garcia-Fernández, Nuria; González-Parra, Emilio; Alcazar, José María; Sánchez, Carmen; Diez-Baylón, José Carlos; Martinez, Pilar; Bartolomé, Javier; Carreño, Vicente

    2008-12-01

    Occult hepatitis C virus (HCV) infection (i.e., detectable HCV-RNA in the liver or peripheral blood mononuclear cells) in the absence of both serum HCV-RNA and anti-HCV antibodies has not been investigated in hemodialysis patients. In this study, real-time PCR and in situ hybridization was used to test for the presence of genomic and antigenomic HCV-RNA in peripheral blood mononuclear cells of 109 hemodialysis patients with abnormal levels of liver enzymes. Occult HCV infection, determined by the presence of genomic HCV-RNA, was found in 45% of the patients; 53% of these patients had ongoing HCV replication, indicated by the presence of antigenomic HCV-RNA. Patients with occult HCV infection had spent a significantly longer time on hemodialysis and had significantly higher mean alanine aminotransferase levels during the 6 mo before study entry. Logistic regression analysis revealed that mortality was associated with age >60 yr (odds ratio 3.30; 95% confidence interval 1.05 to 10.33) and the presence of occult HCV infection (odds ratio 3.84; 95% confidence interval 1.29 to 11.43). In conclusion, the prevalence of occult HCV infection is high among hemodialysis patients with persistently abnormal values of liver enzymes of unknown cause. The clinical significance of occult HCV infection in these patients requires further study.

  12. Proximal Row Carpectomy for Coexisting Kienböck's Disease and Giant Intraosseous Ganglion of the Scaphoid: A Case Report and Review of the Literature

    PubMed Central

    Oellig, Florian; Sánchez, Tomás

    2014-01-01

    The etiologies of Keinböck's disease and intraosseous ganglion remain unknown. Both entities are rare and the coexistence of these two pathologies in the same patient and hand is even less frequent. We report the case of a 40-year-old man with a longstanding history of martial arts practice (karate) who developed an avascular necrosis of the lunate concomitant with a giant intraosseous ganglion of the scaphoid bone successfully managed by proximal row carpectomy. We review the literature of these two diseases. PMID:25530898

  13. Proximal Row Carpectomy for Coexisting Kienböck's Disease and Giant Intraosseous Ganglion of the Scaphoid: A Case Report and Review of the Literature.

    PubMed

    Morón, Miguel; Oellig, Florian; Sánchez, Tomás

    2014-01-01

    The etiologies of Keinböck's disease and intraosseous ganglion remain unknown. Both entities are rare and the coexistence of these two pathologies in the same patient and hand is even less frequent. We report the case of a 40-year-old man with a longstanding history of martial arts practice (karate) who developed an avascular necrosis of the lunate concomitant with a giant intraosseous ganglion of the scaphoid bone successfully managed by proximal row carpectomy. We review the literature of these two diseases.

  14. Digital image enhancement improves diagnosis of nondisplaced proximal femur fractures.

    PubMed

    Botser, Itamar Busheri; Herman, Amir; Nathaniel, Ram; Rappaport, Dan; Chechik, Aharon

    2009-01-01

    Today most emergency room radiographs are computerized, making digital image enhancement a natural advancement to improve fracture diagnosis. We compared the diagnosis of nondisplaced proximal femur fractures using four different image enhancement methods using standard DICOM (Digital Imaging and Communications in Medicine) after window-leveling optimization. Twenty-nine orthopaedic residents and specialists reviewed 28 pelvic images consisting of 25 occult proximal femur fractures and three images with no fracture, using four different image filters and the original DICOM image. For intertrochanteric fractures, the Retinex filter outperforms the other filters and the original image with a correct fracture type diagnosis rate of 50.6%. The Retinex filter also performs well for diagnosis of other fracture types. The Retinex filter had an interobserver agreement index of 53.5%, higher than the other filters. Sensitivity of fracture diagnosis increased to 85.2% when the Retinex filter was combined with the standard DICOM image. Correct fracture type diagnosis per minute for the Retinex filter was 1.43, outperforming the other filters. The Retinex filter may become a valuable tool in clinical settings for diagnosing fractures. Level I, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

  15. Digital Image Enhancement Improves Diagnosis of Nondisplaced Proximal Femur Fractures

    PubMed Central

    Herman, Amir; Nathaniel, Ram; Rappaport, Dan; Chechik, Aharon

    2008-01-01

    Today most emergency room radiographs are computerized, making digital image enhancement a natural advancement to improve fracture diagnosis. We compared the diagnosis of nondisplaced proximal femur fractures using four different image enhancement methods using standard DICOM (Digital Imaging and Communications in Medicine) after window-leveling optimization. Twenty-nine orthopaedic residents and specialists reviewed 28 pelvic images consisting of 25 occult proximal femur fractures and three images with no fracture, using four different image filters and the original DICOM image. For intertrochanteric fractures, the Retinex filter outperforms the other filters and the original image with a correct fracture type diagnosis rate of 50.6%. The Retinex filter also performs well for diagnosis of other fracture types. The Retinex filter had an interobserver agreement index of 53.5%, higher than the other filters. Sensitivity of fracture diagnosis increased to 85.2% when the Retinex filter was combined with the standard DICOM image. Correct fracture type diagnosis per minute for the Retinex filter was 1.43, outperforming the other filters. The Retinex filter may become a valuable tool in clinical settings for diagnosing fractures. Level of Evidence: Level I, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18791776

  16. Spinal fractures in patients with ankylosing spondylitis.

    PubMed

    Leone, Antonio; Marino, Marzia; Dell'Atti, Claudia; Zecchi, Viola; Magarelli, Nicola; Colosimo, Cesare

    2016-10-01

    The ankylosed spine is prone to fracture even after minor trauma due to its changed biomechanical properties. The two central features of ankylosing spondylitis (AS) that promote the pathological remodeling of the spine are inflammation and new bone formation. AS is also associated with osteoporosis that is attributed to an uncoupling of the bone formation and bone resorption processes. Therefore, bone resorption occurs and promotes weakening of the spine as well as increased risk of vertebral fractures which can be hugely different in terms of clinical relevance. Even in the presence of symptomatic clinical vertebral fractures, the diagnosis can be overruled by attributing the pain to disease activity. Furthermore, given the highly abnormal structure of the spine, vertebral fracture diagnosis can be difficult on the basis of radiography alone. CT can show the fractures in detail. Magnetic resonance imaging is considered the method of choice for the imaging of spinal cord injuries, and a reasonable option for exclusion of occult fractures undetected by CT. Since it is equally important for radiologists and clinicians to have a common knowledge base rather than a compartmentalized view, the aim of this review article was to provide the required clinical knowledge that radiologists need to know and the relevant radiological semiotics that clinicians require in diagnosing clinically significant injury to the ankylosed spine.

  17. Hamate fractures.

    PubMed

    Sarabia Condés, J M; Ibañez Martínez, L; Sánchez Carrasco, M A; Carrillo Julia, F J; Salmerón Martínez, E L

    2015-01-01

    The purpose of this paper is to present our experience in the treatment of the fractures of the hamate and to make a review of the literature on this topic. We retrospectively reviewed 10 patients treated in our clinic between 2005-2012 suffering from fractures of the hamate. Six cases were fractures of the body and four were fractures of the hamate. Five cases were of associated injuries. Diagnostic delay ranged from 30 days to 2 years. Patient follow-up ranged from 1 to 10 years. Patient satisfaction was evaluated using the DASH questionnaire. Five patients with a fracture of the body underwent surgery, and one was treated conservatively. Two patients with fracture of the hook of the hamate were treated with immobilization, and two more patients had the fragment removed. The grip strength and the digital clip were reduced in 2 cases. Flexion and extension of the wrist was limited in 3 cases. The mobility of the fingers was normal in all the cases, except in one. The results obtained from the DASH questionnaire were normal in all the cases, except in one case of fracture of the hamate, and in two cases of fracture of the body. The surgical treatment should reduce the dislocation and stabilize the injuries with osteosynthesis. The fractures of the hamate are usually diagnosed late, and the most recommended treatment is removal of the fragment, although it cannot be deduced from this study. Copyright © 2014 SECOT. Published by Elsevier Espana. All rights reserved.

  18. Sizes, Shapes, and Satellites of Asteroids from Occultations

    NASA Astrophysics Data System (ADS)

    Waring Dunham, David; Herald, David Russell; Preston, Steve; Timerson, Bradley; Maley, Paul; Frappa, Eric; Hayamizu, Tsutomu; Talbot, John; Poro, Atila

    2015-08-01

    For 40 years, the sizes and shapes of dozens of asteroids have been determined from observations of asteroidal occultations. Some of the first evidence for satellites of asteroids was obtained from the early efforts; now, the orbits and sizes of some satellites discovered by other means have been refined from occultation observations. Also, several close binary stars have been discovered, and the angular diameters of some stars have been measured from analysis of these observations. The International Occultation Timing Association (IOTA) coordinates this activity worldwide, from predicting and publicizing the events, to accurately timing the occultations from as many stations as possible, and publishing and archiving the observations.The release of the Hipparcos and Tycho catalogs in 1997, from ESA’s Hipparcos space mission, revolutionized asteroidal occultation work, increasing the routine accuracy of the predictions and the annual number of observations by an order of magnitude. IOTA developed an efficient procedure for predicting the occultations using a combination of new star catalogs, based on Hipparcos and new star catalogs, generated mainly at the U. S. Naval Observatory (USNO), and new observations of asteroids relative to the improved astrometric nets mainly from USNO’s Flagstaff Astrometric Scanning Transit Telescope and JPL’s Table Mountain Observatory. In addition, many IOTA observers now use inexpensive low-light-level video cameras and specially built GPS video time inserters to accurately time the events. This automation has also allowed some observers to deploy multiple remote video stations across occultation paths. Then, one observer can record several “chords” across the asteroid. The cameras are sensitive enough that easily-hidden telescopes, many of which can be packed in standard air travel suitcases, can be used for many of the predicted occultations. IOTA’s network of regional coordinators collect and reduce the observations

  19. The treatment of scaphoid nonunion using the Ilizarov fixator without bone graft, a study of 18 cases

    PubMed Central

    2011-01-01

    Objectives Evaluating the safety and efficacy of the Ilizarov fine-wire compression/distraction technique in the treatment of scaphoid nonunion (SNU), without the use of bone graft. Design A retrospective review of 18 consecutive patients in one centre. Patients and Methods 18 patients; 17 males; 1 female, with a mean SNU duration of 13.9 months. Patients with carpal instability, humpback deformity, carpal collapse, avascular necrosis or marked degenerative change, were excluded. Following frame application the treatment consisted of three stages: the frame was distracted 1 mm per day until radiographs showed a 2-3 mm opening at the SNU site (mean 10 days); the SNU site was then compressed for 5 days, at a rate of 1 mm per day, with the wrist in 15 degrees of flexion and 15 degrees of radial deviation; the third stage involved immobilization with the Ilizarov fixator for 6 weeks. The technique is detailed herein. Results Radiographic (CT) and clinical bony union was achieved in all 18 patients after a mean of 89 days (70-130 days). Mean modified Mayo wrist scores improved from 21 to 86 at a mean follow-up of 37 months (24-72 months), with good/excellent results in 14 patients. All patients returned to their pre-injury occupations and levels of activity at a mean of 117 days. Three patients suffered superficial K-wire infections, which resolved with oral antibiotics. Conclusions In these selected patients this technique safely achieved bony union without the need to open the SNU site and without the use of bone graft. PMID:22067958

  20. Not all occult papillary carcinomas are minimal

    SciTech Connect

    Allo, M.D.; Christianson, W.; Koivunen, D.

    1988-12-01

    Occult papillary carcinomas are characterized as small papillary tumors of less than 1.5 cm in maximum diameter, with or without bulky metastatic deposits in cervical nodes. The primary lesion is usually not palpable, and although the clinical behavior usually follows a benign course, tumors with unfavorable histologic features (invasiveness, multifocality) or extrathyroidal disease or a combination of both may not do so. In this report six cases are presented to illustrate this entity. No patient had a history of irradiation to the head or neck. All had primary lesions smaller than 1.5 cm. None had a palpable nodule or abnormal thyroid scan results, and the diagnosis of thyroid cancer was based on cervical lymph node or lung biopsy specimens, which revealed papillary thyroid cancer. All of the patients underwent total or near-total thyroidectomies and were found to have small, invasive papillary lesions with additional metastases to cervical nodes noted at the time of thyroidectomy. Adjunctive treatment consisted of a 5 mCi iodine-131 scan, ablative iodine-131 therapy, and suppression with L-thyroxine. Although distant metastasis to lung or other organs is uncommon and the mortality rate is low (as in larger papillary cancers), these invasive lesions--despite their small size--have a high propensity for recurrence and should be considered to behave more like encapsulated papillary tumors with extrathyroidal extension than like their small, unencapsulated intrathyroidal counterparts.

  1. Starshade design for occulter based exoplanet missions

    NASA Astrophysics Data System (ADS)

    Thomson, Mark W.; Lisman, P. Douglas; Helms, Richard; Walkemeyer, Phil; Kissil, Andrew; Polanco, Otto; Lee, Siu-Chun

    2010-07-01

    We present a lightweight starshade design that delivers the requisite profile figure accuracy with a compact stowed volume that permits launching both the occulter system (starshade and spacecraft) and a 1 to 2m-class telescope system on a single existing launch vehicle. Optimal figure stability is achieved with a very stiff and mass-efficient deployable structure design that has a novel configuration. The reference design is matched to a 1.1m telescope and consists of a 15m diameter inner disc and 24 flower-like petals with 7.5m length. The total tip-to-tip diameter of 30m provides an inner working angle of 75 mas. The design is scalable to accommodate larger telescopes and several options have been assessed. A proof of concept petal is now in production at JPL for deployment demonstrations and as a testbed for developing additional elements of the design. Future plans include developing breadboard and prototype hardware of increasing fidelity for use in demonstrating critical performance capabilities such as deployed optical edge profile figure tolerances and stability thereof.

  2. Starshade Design for Occulter Based Exoplanet Missions

    NASA Technical Reports Server (NTRS)

    Thomson, Mark W.; Lisman, P. Douglas; Helms, Richard; Walkemeyer, Phil; Kissil, Andrew; Polanco, Otto; Lee, Siu-Chun

    2010-01-01

    We present a lightweight starshade design that delivers the requisite profile figure accuracy with a compact stowed volume that permits launching both the occulter system (starshade and spacecraft) and a 1 to 2m-class telescope system on a single existing launch vehicle. Optimal figure stability is achieved with a very stiff and mass-efficient deployable structure design that has a novel configuration. The reference design is matched to a 1.1m telescope and consists of a 15m diameter inner disc and 24 flower-like petals with 7.5m length. The total tip-to-tip diameter of 30m provides an inner working angle of 75 mas. The design is scalable to accommodate larger telescopes and several options have been assessed. A proof of concept petal is now in production at JPL for deployment demonstrations and as a testbed for developing additional elements of the design. Future plans include developing breadboard and prototype hardware of increasing fidelity for use in demonstrating critical performance capabilities such as deployed optical edge profile figure tolerances and stability thereof.

  3. Occult Hepatitis B (OBH) in Clinical Settings

    PubMed Central

    Alavian, Seyed Moayed; Miri, Seyed Mohammad; Hollinger, F. Blaine; Jazayeri, Seyed Mohammad

    2012-01-01

    Context Occult hepatitis B (OHB), or persistent HBV DNA in patients who are hepatitis B surface antigen (HBsAg) negative, is a recently recognized entity. In an attempt to summarize the issues, this review presents an overview of the current proposed hypothesis on the clinical relevance and also updates the knowledge on the classification of OHB in different clinical settings. Evidence Acquisition OHB could be found in different population and clinical backgrounds including: viral co-infections (with either human immunodeficiency or hepatitis C viruses), HBV chronic carriers, dialysis patients, transplantation settings and certain clinical situations (named in here: special clinical settings) with no apparent distinguishable clinical parameters. Results The exact magnitude, pathogenesis, and clinical relevance of OHB are unclear. Even the possible role exerted by this cryptic infection on liver disease outcome, and hepatocellular carcinoma development remains unknown. Conclusions Monitoring of Individuals with positive anti-HBc, mass immunization programs and improvement in diagnostic tools seem to be important to control the probability of transmission of HBV through cryptic HBV infection. PMID:23087749

  4. Gravity wave detection by GPS radio occultations

    NASA Astrophysics Data System (ADS)

    Schmidt, Torsten; Arras, Christina; De la Torre, Alejandro; Alexander, Peter; Llamedo, Pablo

    2016-07-01

    Gravity waves (GWs) play an important role for the general atmospheric circulation due to the related transport of energy and momentum between different regions of the atmosphere. The momentum mostly generated in the troposphere is transported to upper atmospheric levels where GWs break or dissipate and transfer their momentum to the background wind (GW drag). The deposit of GW momentum can occur in the complete altitude range from the upper troposphere-stratosphere, the mesosphere, and even in the thermosphere. A global observation of GW parameters (e.g. potential energy and vertical flux of absolute horizontal momentum) is only possible with satellite data. The radio occultation (RO) technique uses GPS signals received aboard low Earth orbiting satellites for atmospheric limb sounding. Atmospheric temperature profiles in the troposphere/stratosphere and ionospheric electron densities are derived with high vertical resolution. The GPS RO technique is sensitive to GWs with small ratios of vertical to horizontal wavelengths. In this presentation we give an overview about the derivation of GW parameters from RO temperature profiles, review some results of GW detection with RO data, and discuss the limitations of the RO technique. The focus of the presented results is (1) global GW activity in the upper troposphere and lower stratosphere for different seasons, (2) influence of the topography on GW activity from the troposphere to the ionosphere in the Andean region of South America, and (3) the variation of ionospheric sporadic E layers.

  5. Starshade Design for Occulter Based Exoplanet Missions

    NASA Technical Reports Server (NTRS)

    Thomson, Mark W.; Lisman, P. Douglas; Helms, Richard; Walkemeyer, Phil; Kissil, Andrew; Polanco, Otto; Lee, Siu-Chun

    2010-01-01

    We present a lightweight starshade design that delivers the requisite profile figure accuracy with a compact stowed volume that permits launching both the occulter system (starshade and spacecraft) and a 1 to 2m-class telescope system on a single existing launch vehicle. Optimal figure stability is achieved with a very stiff and mass-efficient deployable structure design that has a novel configuration. The reference design is matched to a 1.1m telescope and consists of a 15m diameter inner disc and 24 flower-like petals with 7.5m length. The total tip-to-tip diameter of 30m provides an inner working angle of 75 mas. The design is scalable to accommodate larger telescopes and several options have been assessed. A proof of concept petal is now in production at JPL for deployment demonstrations and as a testbed for developing additional elements of the design. Future plans include developing breadboard and prototype hardware of increasing fidelity for use in demonstrating critical performance capabilities such as deployed optical edge profile figure tolerances and stability thereof.

  6. Predictors of the accuracy of quotation of references in peer-reviewed orthopaedic literature in relation to publications on the scaphoid.

    PubMed

    Buijze, G A; Weening, A A; Poolman, R W; Bhandari, M; Ring, D

    2012-02-01

    Using inaccurate quotations can propagate misleading information, which might affect the management of patients. The aim of this study was to determine the predictors of quotation inaccuracy in the peer-reviewed orthopaedic literature related to the scaphoid. We randomly selected 100 papers from ten orthopaedic journals. All references were retrieved in full text when available or otherwise excluded. Two observers independently rated all quotations from the selected papers by comparing the claims made by the authors with the data and expressed opinions of the reference source. A statistical analysis determined which article-related factors were predictors of quotation inaccuracy. The mean total inaccuracy rate of the 3840 verified quotes was 7.6%. There was no correlation between the rate of inaccuracy and the impact factor of the journal. Multivariable analysis identified the journal and the type of study (clinical, biomechanical, methodological, case report or review) as important predictors of the total quotation inaccuracy rate. We concluded that inaccurate quotations in the peer-reviewed orthopaedic literature related to the scaphoid were common and slightly more so for certain journals and certain study types. Authors, reviewers and editorial staff play an important role in reducing this inaccuracy.

  7. Contact areas of the scaphoid and lunate with the distal radius in neutral and extension: correlation of falling strategies and distal radial anatomy.

    PubMed

    Chen, Y R; Wu, Y F; Tang, J B; Giddins, G

    2014-05-01

    The functional neutral of wrist movement is about 10° extension yet the distal radius has a volar tilt. This has not previously been explained. Assuming that the contact area between the carpus and the distal radius increased in wrist extension this would also help stabilize the carpus on the distal radius in positions where typically there is greater loading. To test this hypothesis we reconstructed three-dimensional structures of the carpal bones and distal radius using computed tomography scans of 13 normal wrists. The contact areas of the scaphoid with the distal radius were measured and were found progressively increased from flexion 20°, neutral, extension 20°, to extension 40°. The maximal increases in the contact area of the scaphoid and the distal radius was at full wrist extension. No significant changes in the contact areas of the lunate with the distal radius were found between the different positions. The contact characteristics provide greater stability to the carpus on the distal radius, and to help spread forces from impact to the wrist reducing the transmitted peak forces and thus the risk of distal radius and carpal injuries.

  8. Effect of interfragmentary gap on compression force in a headless compression screw used for scaphoid fixation.

    PubMed

    Tan, E S; Mat Jais, I S; Abdul Rahim, S; Tay, S C

    2017-04-01

    We investigated the effect of an interfragmentary gap on the final compression force using the Acutrak 2 Mini headless compression screw (length 26 mm) (Acumed, Hillsboro, OR, USA). Two blocks of solid rigid polyurethane foam in a custom jig were separated by spacers of varying thickness (1.0, 1.5, 2.0 and 2.5 mm) to simulate an interfragmentary gap. The spacers were removed before full insertion of the screw and the compression force was measured when the screw was buried 2 mm below the surface of the upper block. Gaps of 1.5 mm and 2.0 mm resulted in significantly decreased compression forces, whereas there was no significant decrease in compression force with a gap of 1 mm. An interfragmentary gap of 2.5 mm did not result in any contact between blocks. We conclude that an increased interfragmentary gap leads to decreased compression force with this screw, which may have implications on fracture healing.

  9. Ankle fracture - aftercare

    MedlinePlus

    Malleolar fracture; Tri-malleolar; Bi-malleolar; Distal tibia fracture; Distal fibula fracture; Malleolus fracture ... Some ankle fractures may require surgery when: The ends of the bone are out of line with each other (displaced). The ...

  10. Distribution of the GNSS-LEO occultation events over Egypt

    NASA Astrophysics Data System (ADS)

    Ghoniem, Ibrahim; Mousa, Ashraf El-Kutb; El-Fiky, Gamal

    2017-06-01

    The space-based GNSS RO technique is a promising tool for monitoring the Earth's atmosphere and ionosphere (Mousa et al., 2006). The current paper presents the distribution of the occultation events over Egypt using the operating LEO satellites and GNSS by its two operating systems. By the present research, Egypt could raise NWP Models efficiency by improving meteorological data quality. Twenty operating LEO missions (e.g. Argentinean SAC-C, European MetOp-A, German TerraSAR-X, Indian OceanSat-2, etc.) sent by different countries all over the world were used to derive the occultation events position through Egypt borders by receiving signal from the American global positioning system (GPS) and the Russian global navigation satellite system (GLONASS). Approximately 20,000 km Altitude satellites are transmitting enormous number of rays by the day to approximately 800 km satellites passing by the Earth atmosphere. Our mission is to derive all of these rays position (start and end) by calculating satellites position by the time, determine the rays in the occultation case and derive the atmosphere tangent point position for all occultating rays on the Earth surface (Occultation Events).

  11. [Occultism, parapsychology and the esoteric from the perspective of psychopathology].

    PubMed

    Scharfetter, C

    1998-10-01

    The concepts and main themes of occultism, parapsychology and esoterics are set in comparison to religion, spirituality, mysticism. The cultural relativity of these concepts is emphasised. Occultism means dealing with phenomena, processes, and/or powers which are not accessible to "normal perception". The manipulation of such powers is effected via (white, black, grey) magic. Parapsychology, in its popular sense, deals with occult phenomena, whereas scientific parapsychology investigates them empirically. Esoterics is a complex of beliefs within a hermetic tradition about occult processes and about desting after death. Transpersonal psychology deals with these issues while calling them "spiritual". Effects of paranormal experiences and actions on the side of the actor as well as the adept are discussed: personality types, interpersonal effects, crises and psychoses (mediumistic psychoses). The concept of dissociation of subpersonalities (subselves) appears to be a viable perspective to explain these phenomena. In mediumistic psychoses, the splitting of non-ego parts of the psyche leads to a manifestation of schizophrenic symptoms. Dangers for mental health are an ego inflation by self-attribution of "superhuman" power. A personality disposition for parapsychological perception and/or action may be seen in schizotypia and similar near-psychotic "personalities up the border". Adepts of occultism may present with a "false self" in the sense of Winnicott.

  12. Radio Occultation Measurements of Pluto's Atmosphere with New Horizons

    NASA Astrophysics Data System (ADS)

    Hinson, D. P.; Linscott, I.; Tyler, G. L.; Bird, M. K.; Paetzold, M.; Strobel, D. F.; Summers, M. E.; Woods, W. W.; Stern, A.; Weaver, H. A., Jr.; Olkin, C.; Young, L. A.; Ennico Smith, K.; Gladstone, R.; Greathouse, T.; Kammer, J.; Parker, A. H.; Parker, J. W.; Retherford, K. D.; Schindhelm, E.; Singer, K. N.; Steffl, A.; Tsang, C.; Versteeg, M.

    2015-12-01

    The reconnaissance of the Pluto System by New Horizons included radio occultations at both Pluto and Charon. This talk will present the latest results from the Pluto occultation. The REX instrument onboard New Horizons received and recorded uplink signals from two 70-m antennas and two 34-m antennas of the NASA Deep Space Network - each transmitting 20 kW at 4.2-cm wavelength - during a diametric occultation by Pluto. At the time this was written only a short segment of data at occultation entry (193°E, 17°S) was available for analysis. The REX measurements extend unequivocally to the surface, providing the first direct measure of the surface pressure and the temperature structure in Pluto's lower atmosphere. Preliminary analysis yields a surface pressure of about 10 microbars, smaller than expected. Data from occultation exit (16°E, 15°N) are scheduled to arrive on the ground in late August 2015. Those observations will yield an improved estimate of the surface pressure, a second temperature profile, and a measure of the diameter of Pluto with a precision of a few hundred meters.

  13. Pros and cons of screening for occult Cushing syndrome.

    PubMed

    Tabarin, Antoine; Perez, Paul

    2011-03-22

    Systematic screening studies performed mainly in patients with diabetes mellitus have revealed an unexpectedly high prevalence of occult Cushing syndrome. Such studies may provide a rationale for systematically screening obese patients with type 2 diabetes mellitus. However, a screening strategy is only justified if it is supported by enough evidence of its efficacy and if the benefits will outweigh drawbacks. To date, the natural history of occult Cushing syndrome and its possible effect on long-term morbidity are unknown. The clinical spectrum of occult Cushing syndrome and its relatively low prevalence may potentially negatively affect the performance of endocrine tests used to diagnose overt Cushing syndrome and generate false positives. Whether the cure of occult Cushing syndrome favorably influences clinical outcomes and is more beneficial than treatment of diabetes mellitus and cardiovascular risk factors with currently available pharmacological tools remains to be demonstrated. Last, the acceptability of a screening program by professionals and the health-care system in terms of workload and costs is highly questionable. Thus, an assessment of the indications for and against screening for occult Cushing syndrome on the basis of currently available data suggests that, to date, the cons surpass the pros.

  14. Crosslink Radio Occultation for the Remote Sensing of Planetary Atmospheres

    NASA Astrophysics Data System (ADS)

    Mannucci, A. J.; Ao, C. O.; Asmar, S.; Edwards, C. D.; Kahan, D. S.; Paik, M.; Pi, X.; Williamson, W.

    2015-12-01

    Radio occultation utilizing deep space telecommunication signals has been used with great success in the profiling of planetary atmospheres and ionospheres since the 1960s. A shortcoming of this technique, however, is the limited temporal and spatial sampling that it provides. We consider a different approach where radio occultation measurements are taken between two spacecraft orbiting an extra-terrestrial body. Such "crosslink" radio occultations between the Global Positioning System satellites and low-earth orbiting spacecraft have been routinely acquired to provide global observations of the Earth's atmosphere and ionosphere that are used for weather forecast, climate analysis, and space weather applications. The feasibility of applying this concept to other planets has recently been demonstrated for the first time, where crosslink occultation measurements have been acquired between the Mars Odyssey and Mars Reconnaissance Orbiter spacecraft. These measurements leverage the proximity link telecommunication payloads on each orbiter, which are nominally used to provide relay communication and navigation services to Mars landers and rovers. In this presentation, we will describe the Mars crosslink experiments and the corresponding data analysis in detail. In addition, we will discuss how the crosslink occultation concepts can be effectively applied in future space exploration missions.

  15. The Lunar Occultation Observer (LOCO) -- A Nuclear Astrophysics All-Sky Survey Mission Concept

    NASA Astrophysics Data System (ADS)

    Miller, R. S.; Bonamente, M.; Burgess, J. M.; Jenke, P.; Lawrence, D. J.; O'Brien, S.; Orr, M. R.; Paciesas, W. S.; Young, C. A.

    2009-03-01

    The Lunar Occultation Observer (LOCO) is a new γ-ray astrophysics mission concept expected to have unprecedented sensitivity in the nuclear regime. Operating in lunar orbit, LOCO will utilize lunar occultation imaging to survey and probe the cosmos.

  16. [Craniofacial fractures].

    PubMed

    Benech, A; Gerbino, G

    1990-12-01

    Results of early combined maxillo-facial and neurosurgical treatment of 53 craniofacial fractures are referred. The fracture location was in 31 cases central midfrontal, 10 lateral supraorbital and 12 combined central and lateral fractures. 35 fractures interested the floor and the posterior wall of frontal sinus, lacerating the underlying dura and cortical tissue. In 19 fractures orbital displacement was present. The key points in the management of these patients are: 1) Early (within 1 to 5 days) and one stage neurosurgical-maxillofacial procedure. Immediate intervention is indicated only in case of evolutive neurological lesions; 2) wide exposition of all the injuries through bicoronal incision and bone flap; 3) assessment of fractures pattern and amount of bone loss; 4) reconstruction of craniofacial frame with osteosynthesis and autologous bone grafts (35 cases iliac crest, 7 split calvarial graft); 5) interosseous wiring is used in sutured mosaic, small bone fragments and intraoperative temporary fixation; miniplates are used for rigid fixation of craniofacial pillars; 6) for optimal cosmetic result reconstruction of supraorbital ridge, nasoglabellar region and zygomatic arch is essential; 7) fractures involving the sinus floor, posterior wall and the nasofrontal duct result in direct communication between the nose and intracranial cavity with high risk of infection and mucocele formation. Cranialization of the sinus removing the posterior wall and all the mucosa is mandatory. The nasofrontal duct, the floor and sinus dead space are obliterated with autologous bone chips. Osteoneogenesis occurred in all the cases.

  17. Fracture line distribution of olecranon fractures.

    PubMed

    Lubberts, Bart; Mellema, Jos J; Janssen, Stein J; Ring, David

    2017-01-01

    The association between specific olecranon fracture characteristics (e.g., displacement, fragmentation, subluxation) and fracture line distribution might help surgeons predict intra-articular fracture location based on fracture characteristics that can be determined on radiographs. We hypothesized that fracture mapping techniques would reveal different fracture patterns for minimally displaced fractures, displaced fractures, and fracture-dislocations of the olecranon. A consecutive series of 78 patients with olecranon fractures were evaluated using initial radiographs and computed tomography scans and characterized according to the Mayo classification. Fracture lines were identified based on reduced three-dimensional computed tomography reconstructions and graphically superimposed onto a standard template to create two-dimensional fracture maps. The fracture maps were then converted into fracture heat maps. Based on fracture and heat maps, fracture line location and patterns were determined. Six (7.7%) patients had a non- or minimally displaced fracture, 22 (28%) a displaced fracture, and 50 (64%) a fracture-dislocation of the olecranon. There were 27 (54%) anterior and 23 (46%) posterior olecranon fracture-dislocations. Fracture lines of non- or minimally displaced fractures and posterior fracture-dislocations enter and exit the trochlear notch at the base of the coronoid, while fracture lines of displaced fractures and anterior fracture-dislocations were spread more broadly over the depths of the trochlear notch. Based on fracture characteristics depicted on radiographs, one can anticipate the amount of the olecranon involved (how close is the fracture line to the coronoid) and the orientation of the fracture line. Computer tomography could be reserved for when more specific knowledge of the fracture line might affect treatment. III.

  18. The occultation of HIP 106829 by Titania

    NASA Astrophysics Data System (ADS)

    Sicardy, B.; Widemann, T.; Colas, F.; Lecacheux, J.; Pau, S.; Thuillot, W.; Beisker, W.; Birnbaum, C.; Hubbard, W. B.; Hill, R. E.; Porto, J.; López, E.; Cósias, R.; Pallo, Edgar; Percz, R.; Pulupa, D.; Simbaña, X.; Yajamín, A.; Recalde, E.

    2001-11-01

    The occultation of the bright star HIP 106829 (V= 7.2, type K0III, distance 170 pc) by the largest Uranian satellite Titania was successfully observed from Europe, several Atlantic and Caribbean islands, and from Southern America, around 2 UT, September 8, 2001. We report here preliminary results obtained from France (80-cm tel. Haute Provence, 100-cm tel. Pic du Midi), Aruba Island (20-cm tel.) and Ecuador (two 20-cm tel. and one 25-cm tel.), using CCD or video recordings, at repetition rates of several images per second. Various other observations, either visual or recorded, by amateurs from Great Britain, Spain, Portugal, Azores, Venezuela and Tobago are still being compiled at the submission date of this abstract. Preliminary examination of the data indicates that no atmosphere at the microbar level is detected near Titania's surface. A detailed analysis is still necessary, however, in order to detect (or put an upper limit on) a hypothetical atmosphere at the 0.1 microbar level or less. The timings of the event at various sites provide the position of Titania with respect to HIP 106829. This will yield the observed-calculated (O-C) shift to apply to Titania position (using the URA027+DE405 ephemeris) in the ICRF/J2000 system. Finally, the finite duration of the immersion and emersion of the star behind Titania will be used to constrain the physical size of this red giant star. Supports from the Programme National de Planétologie (France), Paris Observatory and the NASA Planetary Astronomy grant NAG5-4214 are acknowledged.

  19. Occult HBV infection in the oncohematological setting.

    PubMed

    Sagnelli, C; Macera, M; Pisaturo, M; Zampino, R; Coppola, M; Sagnelli, E

    2016-10-01

    Occult hepatitis B infection (OBI), a virological condition characterized by a low release of Hepatitis B Virus (HBV) from liver cells and low HBV-DNA levels in serum and/or liver tissue of HBsAg-negative subjects, may reactivate in oncohematological patients undergoing immunosuppression by aggressive chemotherapy or hematopoietic stem cell transplantation. The entity of OBI reactivation varies from an increase in HBV replication without liver damage to an active HBV replication followed by liver cell necrosis, frequently severe and in some cases life threatening. Because of a possible severe outcome associated with OBI reactivation (hepatic failure or death due to the discontinuation of chemotherapy), prophylaxis with anti-HBV nucleot(s)ide analogues is recommended in relation to the foreseeable degree of immunosuppression. This review article focuses on the clinical impact of OBI in the oncohematological setting and is addressed to all health care workers having in care oncohematological patients or involved in the treatment of HBV infection and OBI prophylaxis. International guidelines have indicated lamivudine prophylaxis in hematopoietic stem cell transplantation and when high-dose corticosteroids or anti-CD20 or anti-CD52 monoclonal antibodies are used. Entecavir or tenofovir should replace lamivudine for patients with advanced liver diseases for whom reactivation of OBI may be life threatening. When anti-CD20 or anti-CD52 sparing schedules or other non-aggressive chemotherapies are used, monitoring may be indicated, but very early treatment with highly effective antiviral drugs (entecavir or tenofovir) should be administered once a reactivation of OBI has occurred.

  20. Update on occult hepatitis B virus infection.

    PubMed

    Makvandi, Manoochehr

    2016-10-21

    The event of mutations in the surface antigen gene of hepatitis B virus (HBV) results in undetectable hepatitis B surface antigen with positive/negative anti-hepatitis B core (anti-HBc) antibody status in serum and this phenomenon is named occult hepatitis B infection (OBI). The presence of anti-HBc antibody in serum is an important key for OBI tracking, although about 20% of OBI cases are negative for anti-HBc antibody. The diagnosis of OBI is mainly based on polymerase chain reaction (PCR) and real-time PCR assays. However, real-time PCR is a more reliable method than PCR. OBI is a great issue for the public health problem and a challenge for the clinical entity worldwide. The persistence of OBI may lead to the development of cirrhosis and hepatocellular carcinoma. With regard to OBI complications, the screening of HBV DNA by the highly sensitive molecular means should be implemented for: (1) patients with a previous history of chronic or acute HBV infection; (2) patients co-infected with hepatitis C virus/human immunodeficiency virus; (3) patients undergoing chemotherapy or anti-CD20 therapy; (4) recipients of organ transplant; (5) blood donors; (6) organ transplant donors; (7) thalassemia and hemophilia patients; (8) health care workers; (9) patients with liver related disease (cryptogenic); (10) hemodialysis patients; (11) patients undergoing lamivudine or interferon therapy; and (12) children in time of HBV vaccination especially in highly endemic areas of HBV. Active HBV vaccination should be implemented for the close relatives of patients who are negative for OBI markers. Thus, the goal of this review is to evaluate the rate of OBI with a focus on status of high risk groups in different regions of the world.

  1. Update on occult hepatitis B virus infection

    PubMed Central

    Makvandi, Manoochehr

    2016-01-01

    The event of mutations in the surface antigen gene of hepatitis B virus (HBV) results in undetectable hepatitis B surface antigen with positive/negative anti-hepatitis B core (anti-HBc) antibody status in serum and this phenomenon is named occult hepatitis B infection (OBI). The presence of anti-HBc antibody in serum is an important key for OBI tracking, although about 20% of OBI cases are negative for anti-HBc antibody. The diagnosis of OBI is mainly based on polymerase chain reaction (PCR) and real-time PCR assays. However, real-time PCR is a more reliable method than PCR. OBI is a great issue for the public health problem and a challenge for the clinical entity worldwide. The persistence of OBI may lead to the development of cirrhosis and hepatocellular carcinoma. With regard to OBI complications, the screening of HBV DNA by the highly sensitive molecular means should be implemented for: (1) patients with a previous history of chronic or acute HBV infection; (2) patients co-infected with hepatitis C virus/human immunodeficiency virus; (3) patients undergoing chemotherapy or anti-CD20 therapy; (4) recipients of organ transplant; (5) blood donors; (6) organ transplant donors; (7) thalassemia and hemophilia patients; (8) health care workers; (9) patients with liver related disease (cryptogenic); (10) hemodialysis patients; (11) patients undergoing lamivudine or interferon therapy; and (12) children in time of HBV vaccination especially in highly endemic areas of HBV. Active HBV vaccination should be implemented for the close relatives of patients who are negative for OBI markers. Thus, the goal of this review is to evaluate the rate of OBI with a focus on status of high risk groups in different regions of the world. PMID:27818588

  2. Observation and Interpretation of Lunar Occultations. Ph.D. Thesis; [Uranus and beta Capricorni

    NASA Technical Reports Server (NTRS)

    Radick, R. R.

    1978-01-01

    The importance of timings and high resolution astrometry in occultation observations is discussed as well as the occultation process itself. The design and operation of the telescope, photodetector, and data acquisition systems are described. Methods are presented for data analysis and model fitting. Observations of beta Capricorni and Uranus occultations are examined. General conclusions concerning occultation observations are explored and future activities at Prairie Observatory are discussed.

  3. Designing asymmetric and branched petals for planet-finding occulters.

    PubMed

    Cady, Eric; Kasdin, N J; Shaklan, Stuart

    2010-01-18

    One of the proposed methods for finding small extrasolar planets is through use of an occulter, a spacecraft which flies in formation with a space-based telescope to block the light from a star, while leaving nearby planets unaffected. This is accomplished by placing the occulter far enough from the telescope to give it a small angular size, and by carefully choosing the shape to strongly suppress the starlight at the telescope aperture. For most designs, this shape takes the form of a number of bilaterally-symmetric structures called petals, arrayed about a circular central disk. In this paper, we show that the necessary number of petals may be reduced by the introduction of an asymmetry in the petal shape, and describe a a general procedure for producing such a shape by optimization for any occulter with petals. In addition, we show that permitting openings within each petal allows a number of additional modifications to be made without affecting the suppression.

  4. Wave optics of the central spot in planetary occultations

    NASA Technical Reports Server (NTRS)

    Hubbard, W. B.

    1977-01-01

    The detection of a bright central spot during the occultation of epsilon Geminorum by Mars demonstrates that an exponentially-stratified planetary atmosphere can act as a lens providing very high resolution of distant objects (e.g., quasars, white dwarfs, and pulsars). The diffraction nature of the central occultation spot is investigated, with special reference to Mars and Venus. In practice, however, central occultations by these planets are seldom observable from the earth's surface, and spacecraft would have to be used to obtain a suitable orientation for observers. Further difficulties may be encountered in image deconvolution needed for extended objects, in location of the image of a true point source, and in compensation for peculiarities of planets and their atmospheres.

  5. Calculated occultation profiles of Io and the hot spots

    NASA Technical Reports Server (NTRS)

    Mcewen, A. S.; Soderblom, L. A.; Matson, D. L.; Johnson, T. V.; Lunine, J. I.

    1986-01-01

    Occultations of Io by other Galilean satellites in 1985 provide a means to locate volcanic hot spots and to model their temperatures. The expected time variations in the integral reflected and emitted radiation of the occultations are computed as a function of wavelength (visual to 8.7 microns). The best current ephemerides were used to calculate the geometry of each event as viewed from earth. Visual reflectances were modeled from global mosaics of Io. Thermal emission from the hot spots was calculated from Voyager 1 IRIS observations and, for regions unobserved by IRIS, from a model based on the distribution of low-albedo features. The occultations may help determine (1) the location and temperature distribution of Loki; (2) the source(s) of excess emission in the region from long 50 deg to 200 deg and (3) the distribution of small, high-temperature sources.

  6. Detection of occult metastasis in patients with breast cancer.

    PubMed

    Hawes, D; Neville, A M; Cote, R J

    2001-06-01

    The most important factor affecting the outcome of patients with invasive cancer is whether the tumor has spread, either regionally (to regional lymph nodes) or systemically. However, a proportion of patients with no evidence of systemic dissemination will develop recurrent disease after primary "curative" therapy. Clearly, these patients had occult systemic spread of disease that was undetectable by routinely employed methods (careful pathological, clinical, biochemical, and radiological evaluation). In addition, the success of adjuvant therapy is assumed to stem from its ability to eradicate occult metastases before they become clinically evident. Therefore, methods for the detection of occult metastases in patients with the earliest stage of cancer, i.e., prior to detection of metastases by any other clinical or pathological analysis, have received a great deal of attention.

  7. Benefits and harms of detecting clinically occult breast cancer.

    PubMed

    Amir, Eitan; Bedard, Philippe L; Ocaña, Alberto; Seruga, Bostjan

    2012-10-17

    Over the last few decades there has been an increase in the use of strategies to detect clinically occult breast cancer with the aim of achieving diagnosis at an earlier stage when prognosis may be improved. Such strategies include screening mammography in healthy women, diagnostic imaging and axillary staging in those diagnosed with breast cancer, and the use of follow-up imaging for the early detection of recurrent or metastatic disease. Some of these strategies are established, whereas for others there are inconsistent supportive data. Although the potential benefit of early detection of clinically occult breast cancer seems intuitive, use of such strategies can also be associated with harm. In this commentary, we provide an extended discussion on the potential benefits and harms of the routine and frequent use of screening interventions to detect clinically occult breast cancer and question whether we may be causing more harm than good.

  8. Stellar Occultations from Airborne Platforms: 1988 to 2016

    NASA Astrophysics Data System (ADS)

    Bosh, Amanda S.; Dunham, Edward W.; Zuluaga, Carlos; Levine, Stephen; Person, Michael J.; Van Cleve, Jeffrey E.

    2016-10-01

    Observing a stellar occultation by a solar system body with an airborne telescope requires precise positioning of the observer within the shadow cast onto the Earth. For small bodies like Pluto and Kuiper Belt objects, smaller than the Earth, the challenge is particularly intense, with the accuracy of the astrometric and flight planning determining whether the observation succeeds or fails. From our first airborne occultation by Pluto in 1988 aboard the Kuiper Airborne Observatory (KAO), to our most recent event by Pluto in 2015 aboard the Stratospheric Observatory for Infrared Astronomy (SOFIA), we have refined our astrometric and flight planning systems to the point where we can now place an airborne observer into the small central flash zone. We will discuss the history of airborne observation of occultations while detailing the improvements in the astrometric processes. Support for this work was provided by NASA SSO grant NNX15AJ82G to Lowell Observatory.

  9. David Levy's Guide to Eclipses, Transits, and Occultations

    NASA Astrophysics Data System (ADS)

    Levy, David H.

    2010-08-01

    Introduction; Part I. The Magic and History of Eclipses: 1. Shakespeare, King Lear, and the Great Eclipse of 1605; 2. Three centuries later: Einstein, relativity, and the solar eclipse of 1919; 3. What causes solar and lunar eclipses; Part II. Observing Solar Eclipses: 4. Safety considerations; 5. What to expect during a partial eclipse; 6. Annular eclipses and what to see in them; 7. Total eclipse of the Sun: introduction to the magic; 8. The onset: temperature drop, Baily's Beads, Diamond Ring; 9. Totality: Corona, Prominences, Chromosphere, and surrounding area; 10. Photographing and imaging a solar eclipse; Part III. Observing Lunar Eclipses: 11. Don't forget the penumbral eclipses!; 12. Partial lunar eclipses; 13. Total lunar eclipses; 14. Photographing and imaging lunar eclipses; Part IV. Occultations: 15. When the Moon occults a star; Part V. Transits: 16. When planets cross the Sun; Part VI. My Favorite Eclipses: 17. A personal canon of eclipses, occultations, and transits I have seen; Appendices; Index.

  10. Multidetector CT of carpal injuries: anatomy, fractures, and fracture-dislocations.

    PubMed

    Kaewlai, Rathachai; Avery, Laura L; Asrani, Ashwin V; Abujudeh, Hani H; Sacknoff, Richard; Novelline, Robert A

    2008-10-01

    Fractures and dislocations of the carpal bones are more common in young active patients. These injuries can lead to pain, dysfunction, and loss of productivity. Conventional radiography remains the primary imaging modality for evaluation of suspected carpal fractures and dislocations. However, multidetector computed tomography (CT) is playing an increasingly important role, especially in the following situations: (a) when results from initial radiographs are negative in patients with suspected carpal fractures, (b) when initial radiographic findings are indeterminate, and (c) when knowledge of the extent of carpal fractures or dislocations is required before surgical treatment. The advantages of multidetector CT include quick and accurate diagnosis with availability in most emergency centers. Multidetector CT can easily display the extent of carpal fractures and dislocations, often depicting fractures that are occult at radiography. In addition, with multiplanar (two-dimensional) and volumetric (three-dimensional) reformation, pathologic conditions and anatomic relationships are better perceived. This information can be easily conveyed to orthopedic and trauma surgeons and can be crucial for surgical treatment and planning. (c) RSNA, 2008.

  11. Virtopsy -- noninvasive detection of occult bone lesions in postmortem MRI: additional information for traffic accident reconstruction.

    PubMed

    Buck, Ursula; Christe, Andreas; Naether, Silvio; Ross, Steffen; Thali, Michael J

    2009-05-01

    In traffic accidents with pedestrians, cyclists or motorcyclists, patterned impact injuries as well as marks on clothes can be matched to the injury-causing vehicle structure in order to reconstruct the accident and identify the vehicle which has hit the person. Therefore, the differentiation of the primary impact injuries from other injuries is of great importance. Impact injuries can be identified on the external injuries of the skin, the injured subcutaneous and fat tissue, as well as the fractured bones. Another sign of impact is a bone bruise. The bone bruise, or occult bone lesion, means a bleeding in the subcortical bone marrow, which is presumed to be the result of micro-fractures of the medullar trabeculae. The aim of this study was to prove that bleeding in the subcortical bone marrow of the deceased can be detected using the postmortem noninvasive magnetic resonance imaging. This is demonstrated in five accident cases, four involving pedestrians and one a cyclist, where bone bruises were detected in different bones as a sign of impact occurring in the same location as the external and soft tissue impact injuries.

  12. Posterior periosteal disruption in Salter-Harris Type II fractures of the distal femur: evidence for a hyperextension mechanism.

    PubMed

    Kritsaneepaiboon, Supika; Shah, Rajvee; Murray, Martha M; Kleinman, Paul K

    2009-12-01

    Patterns of periosteal disruption are important factors in assessing the mechanism of injury of radiologically evident Salter-Harris (SH) fractures. The purpose of this study is to assess the frequency of posterior periosteal disruption on MRI in radiographically occult or subtle SH type II fractures of the distal femur and to evaluate associated soft-tissue findings that support a hyperextension mechanism of injury. We found that all children in our experience with occult or subtle SH type II fractures of the distal femur have posterior periosteal disruption and other MRI findings to indicate a hyperextension mechanism of injury. Direct indicators of fracture may be inconspicuous, and the presence of posterior periosteal disruption is a clue that should prompt a search for other features of this serious pediatric injury, which may be followed by limb shortening or angular deformity.

  13. Exploring small bodies in the outer solar system with stellar occultations

    NASA Technical Reports Server (NTRS)

    Elliot, Jim L.; Dunham, Edward W.; Olkin, C. B.

    1995-01-01

    Stellar occultation observations probe the atmospheric structure and extinction of outer solar system bodies with a spatial resolution of a few kilometers, and an airborne platform allows the observation of occultations by small bodies that are not visible from fixed telescopes. Results from occultations by Triton, Pluto, and Chiron observed with KAO are discussed, and future directions for this program are presented.

  14. Scintillations during occultations by planets. 1. An approximate theory. [fresnel region

    NASA Technical Reports Server (NTRS)

    Young, A. T.

    1975-01-01

    Scintillations observed during occultations of both stars and spacecraft by planetary atmospheres are discussed theoretically. The effects of severe flattening of the Fresnel zone or source image by defocusing on occultations are presented, along with temporal power spectra. Other topics discussed include atmospheric turbulence, saturation of scintillation, effects of saturation on occultation curves, and some methods for a more accurate determination of atmospheric structure.

  15. Sonographic Findings of Chondral Avulsion Fractures of the Lateral Ankle Ligaments in Children.

    PubMed

    Maeda, Manabu; Maeda, Nana; Takaoka, Takanori; Tanaka, Yasuhito

    2017-02-01

    In this series, we aimed to describe the sonographic findings of chondral avulsion fractures that develop concomitant with lateral ankle ligament injury in children. We performed stress sonography during a manual anterior drawer stress procedure of the ankle in 9 skeletally immature patients who had recently had a lateral ankle sprain. Echo videos were obtained through the course of treatment, and all videos were reviewed. We elucidated the common features of chondral avulsion fractures of the lateral ankle ligaments in the children. The features of avulsion fractures on conventional sonography included absence of a fracture with hyperechoic spots (sonographic occult fracture type), cortical discontinuity with hyperechoic spots (cortical disruption fracture type), fracture line in the cortical bone (double-line fracture type), and a step-off deformity of the cortical bone with cartilage (displaced fracture type). In contrast, the features of chondral fractures on stress sonography included abnormal motion of the chondral lesions and mobility/fluidity of hyperechoic spots along the chondral fracture site. The presence of hyperechoic spots around the chondral lesion is an important sonographic sign for diagnosing chondral fractures concomitant with ankle lateral ligament injury. Hence, we believe that stress sonography should be considered for the detection of chondral fractures concomitant with radiographically negative ankle lateral ligament injuries in skeletally immature patients with lateral ankle pain and ankle sprains, if hyperechoic spots are present in the cartilage of the distal fibula. © 2017 by the American Institute of Ultrasound in Medicine.

  16. The Burst and Transient Source Experiment Earth Occultation Technique

    NASA Technical Reports Server (NTRS)

    Harmon, B. A.; Fishman, G. J.; Wilson, C. A.; Paciesas, W. S.; Zhang, S. N.; Finger, M. H.; Koshut, T. M.; McCollough, M. L.; Robinson, C. R.; Rubin, B. C.

    2002-01-01

    An Earth orbiting detector sensitive to gamma-ray photons will see step-like occultation features in its count rate when a gamma-ray point source crosses the Earth's limb. This is due to the change in atmospheric attenuation of the gamma rays along the line of sight. In an uncollimated detector, these occultation features can be used to locate and monitor astrophysical sources provided their signals can be individually separated from the detector background. We show that the Earth occultation technique applied to the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory (CGRO) is a viable and flexible all-sky monitor in the low-energy gamma-ray and hard X-ray energy range (20 keV-1 MeV). The method is an alternative to more sophisticated photon imaging devices for astronomy and can serve well as a cost-effective science capability for monitoring the high energy sky. Here we describe the Earth occultation technique for locating new sources and for measuring source intensity and spectra without the use of complex background models. Examples of transform imaging, step searches, spectra, and light curves are presented. Systematic uncertainties due to source confusion, detector response, and contamination from rapid background fluctuations are discussed and analyzed for their effect on intensity measurements. A sky location-dependent average systematic error is derived as a function of Galactic coordinates. The sensitivity of the technique is derived as a function of incident photon energy and also as a function of angle between the source and the normal to the detector entrance window. Occultations of the Crab Nebula by the Moon are used to calibrate Earth occultation flux measurements independent of possible atmospheric scattering effects.

  17. The Burst and Transient Source Experiment Earth Occultation Technique

    NASA Technical Reports Server (NTRS)

    Harmon, B. A.; Fishman, G. J.; Wilson, C. A.; Paciesas, W. S.; Zhang, S. N.; Finger, M. H.; Koshut, T. M.; McCollough, M. L.; Robinson, C. R.; Rubin, B. C.

    2002-01-01

    An Earth orbiting detector sensitive to gamma-ray photons will see step-like occultation features in its count rate when a gamma-ray point source crosses the Earth's limb. This is due to the change in atmospheric attenuation of the gamma rays along the line of sight. In an uncollimated detector, these occultation features can be used to locate and monitor astrophysical sources provided their signals can be individually separated from the detector background. We show that the Earth occultation technique applied to the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory (CGRO) is a viable and flexible all-sky monitor in the low-energy gamma-ray and hard X-ray energy range (20 keV-1 MeV). The method is an alternative to more sophisticated photon imaging devices for astronomy and can serve well as a cost-effective science capability for monitoring the high energy sky. Here we describe the Earth occultation technique for locating new sources and for measuring source intensity and spectra without the use of complex background models. Examples of transform imaging, step searches, spectra, and light curves are presented. Systematic uncertainties due to source confusion, detector response, and contamination from rapid background fluctuations are discussed and analyzed for their effect on intensity measurements. A sky location-dependent average systematic error is derived as a function of Galactic coordinates. The sensitivity of the technique is derived as a function of incident photon energy and also as a function of angle between the source and the normal to the detector entrance window. Occultations of the Crab Nebula by the Moon are used to calibrate Earth occultation flux measurements independent of possible atmospheric scattering effects.

  18. GRAS radio occultation on-board of Metop

    NASA Astrophysics Data System (ADS)

    von Engeln, A.; Andres, Y.; Marquardt, C.; Sancho, F.

    2011-01-01

    The GRAS radio occultation instrument is flying on Metop-A and belongs to the EPS (EUMETSAT Polar System). GRAS observes GPS satellites in occultation. Within this work, validation of GRAS closed-loop bending angle data against co-located ECMWF profiles extracted from model fields and occultations from the COSMIC constellation of radio occultation instruments is shown. Results confirm the high data quality and robustness, where GRAS shows lower bending angle noise against ECMWF than COSMIC and in terms of occultations per day, one GRAS ≈ two COSMIC satellites. This is partly due to the operational setup of EPS. For the investigation we focus on two observation periods where updates in the ECMWF (March 2009) and COSMIC processing (October 2009) have improved the statistics further. Bending angles biases agree to within 0.5% against ECMWF and to within 0.1% against COSMIC after the updates for altitudes between 8 and 40 km. In addition, we also analyze the impact of the Metop orbit processing on the derived GRAS bending angle data, where different GPS and Metop orbit solutions are analyzed. Results show that a batch based orbit processing would improve in particular the bending angle bias behavior at higher altitudes. Requirements for the operational processing of GRAS data are briefly outlined, options to ease the use of other positioning system satellites in the near future are discussed. A simplified analysis on the observation of several of these systems, e.g. GPS and Galileo, from one platform shows that about 16% of occultations are found within 300 km, ±3 h, thus providing similar information. A constellation of 2 GRAS like instruments would have only about 10% close-by.

  19. Constraints on Pluto's Hazes from 2-Color Occultation Lightcurves

    NASA Astrophysics Data System (ADS)

    Hartig, Kara; Barry, T.; Carriazo, C. Y.; Cole, A.; Gault, D.; Giles, B.; Giles, D.; Hill, K. M.; Howell, R. R.; Hudson, G.; Loader, B.; Mackie, J. A.; Olkin, C. B.; Rannou, P.; Regester, J.; Resnick, A.; Rodgers, T.; Sicardy, B.; Skrutskie, M. F.; Verbiscer, A. J.; Wasserman, L. H.; Watson, C. R.; Young, E. F.; Young, L. A.; Buie, M. W.; Nelson, M.

    2015-11-01

    The controversial question of aerosols in Pluto's atmosphere first arose in 1988, when features in a Pluto occultation lightcurve were alternately attributed to haze opacity (Elliot et al. 1989) or a thermal inversion (Eshleman 1989). A stellar occultation by Pluto in 2002 was observed from several telescopes on Mauna Kea in wavelengths ranging from R- to K-bands (Elliot et al. 2003). This event provided compelling evidence for haze on Pluto, since the mid-event baseline levels were systematically higher at longer wavelengths (as expected if there were an opacity source that scattered more effectively at shorter wavelengths). However, subsequent occultations in 2007 and 2011 showed no significant differences between visible and IR lightcurves (Young et al. 2011).The question of haze on Pluto was definitively answered by direct imaging of forward-scattering aerosols by the New Horizons spacecraft on 14-JUL-2015. We report on results of a bright stellar occultation which we observed on 29-JUN-2015 in B- and H-bands from both grazing and central sites. As in 2007 and 2011, we see no evidence for wavelength-dependent extinction. We will present an analysis of haze parameters (particle sizes, number density profiles, and fractal aggregations), constraining models of haze distribution to those consistent with and to those ruled out by the occultation lightcurves and the New Horizons imaging.References:Elliot, J.L., et al., "Pluto's Atmosphere." Icarus 77, 148-170 (1989)Eshleman, V.R., "Pluto's Atmosphere: Models based on refraction, inversion, and vapor pressure equilibrium." Icarus 80 439-443 (1989)Elliot, J.L., et al., "The recent expansion of Pluto's atmosphere." Nature 424 165-168 (2003)Young, E.F., et al., "Search for Pluto's aerosols: simultaneous IR and visible stellar occultation observations." EPSC-DPS Joint Meeting 2011, held 2-7 October 2011 in Nantes, France (2011)

  20. Deriving Saturn's Zonal Winds from Cassini Radio Occultations

    NASA Astrophysics Data System (ADS)

    Flasar, F. Michael; Schinder, Paul J.

    2015-11-01

    Tracking cloud features from visible images have provided detailed maps of the meridional variation of the mean zonal winds on the giant planets, including Saturn. Filters at different wavelengths can provide information on the vertical structure of the zonal winds, but that is approximate, and the altitudes of winds observed with a given filter generally vary with location, because cloud heights do. Radio occultations provide vertical profiles of refractivity, pressure, and temperature vs. altitude. Zonal winds can be derived from the assumption of gradient wind balance, which relates the zonal wind to the change of geopotential height with latitude along an isobar. Occultations have the advantage that vertical profiles of winds can be obtained in the troposphere and stratosphere. There are, however, complicating factors. In general, the meridional distribution of occultation soundings is limited and unevenly distributed. Moreover, one needs to know the geometry of the occulting atmosphere to correctly account for the path of the refracted radio signal. The zonal winds matter, because they distort isobaric surfaces. For example, an inversion that includes Saturn's oblateness from uniform rotation, based on the Voyager System III period, would yield equatorial temperature profiles that are shifted by ~ 2 K relative to one that also includes the differential rotation associated with the cloud-tracked zonal winds. In retrieving vertical profiles of atmospheric variables from occultation soundings, one also needs an additional symmetry assumption to make the inversions tractable. Typically one uses the zonal winds based on cloud-tracking studies, and assumes they are axisymmetric and barotropic, so that both the gravitational and centrifugal forces are derivable from a potential, and the surfaces of constant geopotential height, pressure, and temperature coincide. This forms the basis for an iterative approach. The pressures and temperatures so retrieved from the

  1. Detection of Small Kuiper Belt Objects by Stellar Occultation

    NASA Astrophysics Data System (ADS)

    Georgevits, George

    2006-09-01

    We present here the results for the first attempt to survey the sub-kilometre radius KBO population by stellar occultation. Using the unique capabilities of the 1.2m UK Schmidt Telescope (Anglo Australian Observatory, Australia), in conjunction with the 6df Spectrograph, by simultaneously monitoring 100 suitably selected stars, we were able to embark upon an occultation observation program which yielded 7,000 hours of stellar light curves, with 10 millisecond resolution. Initial data reduction indicates that we have captured many events which resemble occultation events, in so far as the light curves of recorded events typically match that which may be expected when a small KBO occults a distant star. Logged events are spread over many pixels, with 10 pixels (corresponding to 100 milliseconds) being the typical event duration. By simultaneously monitoring many stars in the same field, false events are eliminated. Most runs monitored blue stars located at 2kpcs. As a sanity check, one night's observing monitored close F and G class stars in the same field. The event statistics for the distant and the close star cases are consistent with occultations caused by KBO's. As an additional confirmation, it was found that the observation results at 30o and 60o past opposition give the expected 50% fall in event rate due to the change in observing geometry. It is estimated that many of the events logged correspond to occultations which would be caused by objects down to 300m radius. As the next step, it is hoped to construct a purpose-built 2,000 fibre instrument and to conduct a complete survey of the Kuiper Belt. We wish to express our thanks to the Anglo Australian Observatory for their technical assistance and telescope time.

  2. Saturn's variable thermosphere from Cassini/UVIS occultations

    NASA Astrophysics Data System (ADS)

    Koskinen, T. T.; Sandel, B. R.; Yelle, R. V.; Strobel, D. F.; Müller-Wodarg, I. C. F.; Erwin, J. T.

    2015-11-01

    We retrieved the density and temperature profiles in Saturn's thermosphere from 26 stellar occultations observed by the Cassini/UVIS instrument. These results expand upon and complement the previous analysis of 15 Cassini/UVIS solar occultations by Saturn's upper thermosphere. We find that the exospheric temperatures based on the stellar occultations agree with the solar occultations and range from 380 K to 590 K. These temperatures are also consistent with the recent re-analysis of the Voyager/UVS occultations. The retrieved density profiles support our earlier inference that the shape of the atmosphere at low pressures is consistent with a meridional trend of increasing temperatures with absolute latitude. This implies a high-latitude heat source, such as auroral heating, although the existing circulation models that include auroral heating still underestimate the equatorial temperatures by overestimating the meridional temperature gradient. This suggests either that the circulation models are somehow incomplete or there is some other heat source at low to mid latitudes that is relatively less efficient than high-latitude heating. We also find evidence for the expansion of the exobase by about 500 km between 2006 and 2011 near the equator, followed by possible contraction after 2011. The expansion appears to be caused by significant warming of the lower thermosphere that anti-correlates with solar activity and may be connected to changes in global circulation. Lastly, we note that our density profiles are in good general agreement with the Voyager/UVS data. In particular, the Voyager density profiles are most consistent with the Cassini/UVIS stellar occultations from late 2008 and early 2009 that roughly coincide in season with the Voyager flybys.

  3. The occultation of AG+29 deg 398 by 98 Minerva

    NASA Technical Reports Server (NTRS)

    Millis, R. L.; Wasserman, L. H.; Bowell, E.; Franz, O. G.; Nye, R.; Osborn, W.; Klemola, A.

    1984-01-01

    On 22 Nov. 1982, the asteroid 93 Minerva occulted AG-29 deg 398 (= SAO 76O17A), a seventh magnitude star of AO spectral type. The data were best fitted by a circular limb profile having a diameter of 170.8 + or - 1.4 km, a value that agrees well with the published radiometric diameter for this asteroid. However, evidence of significant departure from a spherical shape is found in the occultation observations and in photometric measurements of Minerva. Additional observations are required to specify difinitively the three dimensional figure of Minerva.

  4. The occultation of AG + 29 deg 398 by 93 Minerva

    NASA Technical Reports Server (NTRS)

    Millis, R. L.; Wasserman, L. H.; Bowell, E.; Franz, O. G.; Nye, R.; Osborn, W.; Klemola, A.

    1985-01-01

    The occultation of AG + 29 deg 398 by 93 Minerva on 22 November 1982 was successfully observed at 10 sites. The data are best fitted by a circular limb profile having a diameter of 170.8 + or - 1.4 km, a value that agrees well with the published radiometric diameter for this asteroid. However, evidence of significant departure from a spherical shape is found in the occultation observations and in photometric measurements of Minerva made at Lowell Observatory over several months. Additional observations are needed to specify definitively the three-dimensional figure of Minerva.

  5. The mermaid malformation: cloacal exstrophy and occult spinal dysraphism.

    PubMed

    Cohen, A R

    1991-06-01

    Five infants with cloacal exstrophy underwent neurological evaluation and radiographic examination of the caudal spine shortly after birth. Each was found to have occult spinal dysraphism. Four had terminal myelocystoceles, and one had a lipomyelomeningocele. Pathological anatomy was confirmed during surgery for the release of the tethered spinal cords. The striking association between cloacal exstrophy and occult spinal dysraphism suggests a common developmental defect in the caudal pole of the embryo. A hypothesis is offered to explain this association. Terminal myelocystocele and lipomyelomeningocele appear to be part of a continuum of lesions associated with skin-covered spina bifida.

  6. Cassini First Diametric Radio Occultation of Saturn's Rings

    NASA Astrophysics Data System (ADS)

    Marouf, E.; French, R.; Rappaport, N.; Kliore, A.; Flasar, M.; Nagy, A.; Ambrosini, R.; McGhee, C.; Schinder, P.; Anabtawi, A.; Barbinis, E.; Goltz, G.; Thomson, F.; Wong, K.

    2005-05-01

    We present preliminary results expected from the first planned Cassini radio occultation observation of Saturn's rings, to be conducted on May 3rd, 2005. The path of Cassini as seen from Earth (the occultation track) has been designed to cross the rings from the west to the east ansa almost diametrically, allowing for occultation of all major ring features at two widely separated longitudes (about 180 deg apart). The duration of the geometric occultation is about 1.5 hours on each side. During the occultation, Cassini transmits through the rings three coherent monochromatic radio signals of wavelength 0.94, 3.6, and 13 cm (Ka-, X-, and S-band respectively), a capability unique to Cassini. The perturbed signals received at the Earth are recorded at the NASA DSN complexes at Goldstone and Canberra. Both direct and forward-scattered components of the signal may be identified in spectrograms of the received signals. The time history of the extinction of the direct signal is expected to yield high-spatial-resolution optical depth and phase shift profiles of ring structure. The timing of the occultation was optimized to allow probing the rings when the ring-opening-angle B (the angle between the line-of-sight and the ring plane) is relatively large (B = 23 deg), hence maximizing chances of measuring for the first time the structure of the relatively optically thick Ring B. In a similar experiment by Voyager in 1980, excessive signal attenuation along the long path within the nearly closed rings (B = 5.9 deg) limited the utility of the observations in relatively thick ring regions, in particular the main Ring B. For the Cassini optimized occultation geometry, a large B, slow radial velocity along the occultation track, and much improved phase stability of the reference ultrastable oscillator (USO) on board Cassini combine to promise achievable radial resolution approaching 100 m over a good fraction of the rings. Measurement of the amplitude and phase of the diffracted

  7. IRTF observations of the occultation of 28 SGR by Saturn

    NASA Astrophysics Data System (ADS)

    Harrington, J.; Cooke, M. L.; Forrest, W. J.; Pipher, J. L.; Dunham, E. W.; Elliot, J. L.

    1993-06-01

    NASA's Mauna Kea IR Telescope Facility obtained an IR-imaging time series for the July 3, 1989 occultation of 28 Sgr by Saturn and its rings; the stellar signal is present in these images throughout the ring occultation event. These data are noted to vary systematically with respect to the Voyager data over large radius scales, perhaps due to stellar signal diffraction through the rings. The stellar diameter, which is projected to be about 20 km, placed most bending- and density-wave trains below measurable resolution. Masses and mean optical depths are presented for individual ring sections.

  8. Forthcoming Occultations of Astrometric Radio Sources by Planets

    NASA Technical Reports Server (NTRS)

    L'vov, Victor; Malkin, Zinovy; Tsekmeister, Svetlana

    2010-01-01

    Astrometric observations of radio source occultations by solar system bodies may be of large interest for testing gravity theories, dynamical astronomy, and planetary physics. In this paper, we present an updated list of the occultations of astrometric radio sources by planets expected in the coming years. Such events, like solar eclipses, generally speaking can only be observed in a limited region. A map of the shadow path is provided for the events that will occurr in regions with several VLBI stations and hence will be the most interesting for radio astronomy experiments.

  9. The occultation of AG + 29 deg 398 by 93 Minerva

    NASA Technical Reports Server (NTRS)

    Millis, R. L.; Wasserman, L. H.; Bowell, E.; Franz, O. G.; Nye, R.; Osborn, W.; Klemola, A.

    1985-01-01

    The occultation of AG + 29 deg 398 by 93 Minerva on 22 November 1982 was successfully observed at 10 sites. The data are best fitted by a circular limb profile having a diameter of 170.8 + or - 1.4 km, a value that agrees well with the published radiometric diameter for this asteroid. However, evidence of significant departure from a spherical shape is found in the occultation observations and in photometric measurements of Minerva made at Lowell Observatory over several months. Additional observations are needed to specify definitively the three-dimensional figure of Minerva.

  10. Cassini UVIS highest resolution occultations of Saturn's rings

    NASA Astrophysics Data System (ADS)

    Sremcevic, Miodrag; Esposito, L. W.; Colwell, J.

    2013-10-01

    Since the beginning of the Cassini mission in 2004 the UVIS instrument has recorded >100 stellar occultations of Saturn's rings. Despite achieved radial resolutions of <1m true resolution is limited by the orbital motion of particles. These can move by almost 20m during a 1ms integration period, effectively smearing the ring profile. In order to achieve superior true resolution we designed a special type of observations, dubbed tracking occultations, where the spacecraft velocity projected onto the rings cancels the orbital motion of ring particles. The ring particles are thus nearly motionless in the field of view of UVIS instrument and essentially tracked. So far Cassini UVIS has recorded two "tracking" occultations of mid-A ring, one of the inner A ring, and one of the so called A ring ramp (a transition region between Cassini division and A ring). The occultations have at least 2m true resolution limited only by diffraction. The two mid-A ring occultations for the first time directly resolve the self-gravity (SG) Toomre like wakes. The SG wakes show as a train of opaque regions (tau>1.5) and nearly transparent gaps (tau<0.05). The observed opaque wakes can be as large as 200m, while transparent gaps are somewhat shorter (L<100m). The opaque and transparent regions are interspersed with material in an intermittent state (0.05occultation of the A ring ramp also reveals clear SG wakes. While the image is still of a chain of wakes and gaps, the wake region is not opaque nor is the transition between a gap and wake state as sharp. The structures are about 5 times smaller compared to mid-A ring, indicating a much smaller surface density. The inner A ring "tracking" occultation turns to be the most surprising since it doesn't show any clear SG wakes. While statistical and spectral analysis of the data show that some kind of structure is present there is no clear ubiquitous sign of classical SG wakes as in other 3 "tracking

  11. GOMOS: Gobal Ozone Monitoring by Occultation of Stars

    NASA Technical Reports Server (NTRS)

    Leppelmeier, G. W.; Kyrola, E.; Pellinen, R.; Merat, P.; Korpela, S.; Bertaux, J. L.; Chassefiere, E.; Dalaudier, F.; Megie, G.

    1994-01-01

    In this paper we report on the progress and status of the Global Ozone Monitoring by Occultation of Stars (GOMOS) instrument, and imaging spectrometer under development for flight on the European Space Agency's Polar Orbiting Earth Mission (POEM-1) mission in 1998. Employing occultation of stars as a light probe of the Earth's atmosphere from a sun-sychronous polar orbit, the instrument will monitor ozone and other atmospheric trace gases over the entire globe. Atmospheric transmission resolution of approximately 1.7 km. When data are combined regionally, it will be possible to detect ozone concentration trends as small as 0.05 percent/year, depending on the degree of combination.

  12. Results from the occultation of 14 Piscium by (51) Nemausa

    NASA Technical Reports Server (NTRS)

    Dunham, E. W.; Baron, R. L.; Conner, S.; Dunham, D. W.; Dunham, J. B.; Schneider, G.; Cohen, H. L.; Helms, V. T., III; Croom, M.; Safko, J.

    1984-01-01

    Observations of the September 11, 1983 occultation of 14 Psc by the asteroid (51) Nemausa were obtained at six sites distributed across the northern two-thirds of the track. The observations are well represented by an elliptical limb profile with a semimajor axis of 84.9 + or - 2.0 km and oblateness (1-b'/a') 0.20 + or - 0.05. The mean radius of 74 + or - 4 km agrees with the 1979 occultation effective radius of 76.5 + or - 4 km and the published radiometric radius of 75.5 km (Morrison and Zellner, 1979).

  13. Choosing antenna aimpoints during occultations - A simple method for Galileo

    NASA Technical Reports Server (NTRS)

    Wolf, Aron A.

    1988-01-01

    Attempts have been made to design the trajectory of the Galileo orbiter so that it passes behind Jupiter, as viewed from earth, as many times as possible during the mission. During this type of pass, or occultation, the thick Jovian atmosphere acts as a lens, refracting a portion of the radio signal from the spacecraft toward earth. A method for calculating antenna aiming vectors during occultations is presented. This method meets the necessary accuracy requirements while offering a reduction in terms of complexity and usage of computer resources.

  14. Hip Fracture

    MedlinePlus

    ... make older people more likely to trip and fall — one of the most common causes of hip ... Taking steps to maintain bone density and avoid falls can help prevent hip fracture. Signs and symptoms ...

  15. Fracture Management

    MedlinePlus

    ... to hold the fracture in the correct position. • Fiberglass casting is lighter and stronger and the exterior ... with your physician if this occurs. • When a fiberglass cast is used in conjunction with a GORE- ...

  16. Epidemiology of Fracture Nonunion in 18 Human Bones.

    PubMed

    Zura, Robert; Xiong, Ze; Einhorn, Thomas; Watson, J Tracy; Ostrum, Robert F; Prayson, Michael J; Della Rocca, Gregory J; Mehta, Samir; McKinley, Todd; Wang, Zhe; Steen, R Grant

    2016-11-16

    Failure of bone fracture healing occurs in 5% to 10% of all patients. Nonunion risk is associated with the severity of injury and with the surgical treatment technique, yet progression to nonunion is not fully explained by these risk factors. To test a hypothesis that fracture characteristics and patient-related risk factors assessable by the clinician at patient presentation can indicate the probability of fracture nonunion. An inception cohort study in a large payer database of patients with fracture in the United States was conducted using patient-level health claims for medical and drug expenses compiled for approximately 90.1 million patients in calendar year 2011. The final database collated demographic descriptors, treatment procedures as per Current Procedural Terminology codes; comorbidities as per International Classification of Diseases, Ninth Revision codes; and drug prescriptions as per National Drug Code Directory codes. Logistic regression was used to calculate odds ratios (ORs) for variables associated with nonunion. Data analysis was performed from January 1, 2011, to December 31, 2012. Continuous enrollment in the database was required for 12 months after fracture to allow sufficient time to capture a nonunion diagnosis. The final analysis of 309 330 fractures in 18 bones included 178 952 women (57.9%); mean (SD) age was 44.48 (13.68) years. The nonunion rate was 4.9%. Elevated nonunion risk was associated with severe fracture (eg, open fracture, multiple fractures), high body mass index, smoking, and alcoholism. Women experienced more fractures, but men were more prone to nonunion. The nonunion rate also varied with fracture location: scaphoid, tibia plus fibula, and femur were most likely to be nonunion. The ORs for nonunion fractures were significantly increased for risk factors, including number of fractures (OR, 2.65; 95% CI, 2.34-2.99), use of nonsteroidal anti-inflammatory drugs plus opioids (OR, 1.84; 95% CI, 1.73-1.95), operative

  17. Lisfranc fractures.

    PubMed

    Wright, Amanda; Gerhart, Ann E

    2009-01-01

    Injuries of the tarsometatarsal, or Lisfranc, joint are rarely seen. Lisfranc fractures and fracture dislocations are among the most frequently misdiagnosed foot injuries in the emergency department. A misdiagnosed injury may have severe consequences including chronic pain and loss of foot biomechanics. Evaluation of a foot injury should include a high level of suspicion of a Lisfranc injury, and a thorough work-up is needed for correct diagnosis.

  18. Colles' fracture.

    PubMed

    Altizer, Linda L

    2008-01-01

    Many people "slip and fall", especially in the icy areas of the winter season. To prevent an injury to the head, most people put their hand out to hit the ground first, so the wrist usually gets injured. The most frequent injury from this type of "intervention" is a fracture to the distal radius and/or ulna, which is frequently called a "Colles' fracture."

  19. Boxer's fracture.

    PubMed

    Altizer, Linda

    2006-01-01

    Boxer's fracture is a common name for a fracture of the distal fifth metacarpal and received its name from one of its most common causes, punching an object with a closed fist. It can occur from a fistfight or from punching a hard object. The injury of a "Boxer's Fracture" earned the name from the way in which the injury occurred, punching an immovable object with a closed fist and no boxing mitt (Figure 1). Naturally, a "Boxer" usually punches his fist into his opponent's face or body. An angry person may perform the same action into a person, or into the wall. The third person may be performing a task and strike something with his fist with forceful action accidentally. In any event, if the closed fist "punches" into an immovable or firm object with force, the most frequent injury sustained would be a fracture of the fifth metacarpal neck. Some caregivers would also call a fourth metacarpal neck fracture a boxer's fracture.

  20. Follow-up of occult bone lesions detected at MR imaging: systematic review.

    PubMed

    Boks, Simone S; Vroegindeweij, Dammis; Koes, Bart W; Hunink, M G Myriam; Bierma-Zeinstra, Sita M A

    2006-03-01

    To perform a systematic review of the literature regarding the natural course of posttraumatic occult bone lesions (often referred to as bone bruises) detected at magnetic resonance (MR) imaging. A systematic review of the literature was performed by searching the MEDLINE database (from January 1966 to February 2003) with the keywords bone bruise, trauma, follow-up, and MRI. Keywords were linked by using the Boolean operator AND. Studies were included if all of the following criteria were fulfilled: patients sustained trauma, MR imaging was used as a diagnostic method, results of clinical or MR imaging follow-up were available, and study was written in English, Dutch, German, French, Spanish, Italian, Swedish, Danish, or Norwegian. The quality of each study was assessed by using a standardized criteria set, and kappa statistics were estimated to rate the level of agreement between the two reviewers. Results were compared with regard to study design and quality scores. The MEDLINE search identified 266 articles, 13 of which met the inclusion criteria. The quality of the included studies was moderate. The two reviewers initially agreed on 179 quality items (kappa = 0.84). The study population was generally small, and follow-up periods ranged from 1 to 73 months. Four different classification systems were used, and in two studies bone bruise was not specified. Study results suggest a generally good clinical prognosis of bone bruises. Normalization of MR imaging appearance is possible and is most often encountered after the occurrence of reticular lesions. Cartilage loss at follow-up is often found in cases of initial cartilage damage (impaction or osteochondral fracture). In general, a healing response was often encountered after sustained posttraumatic occult bone lesions. The initial MR imaging appearance appears to have prognostic value. Copyright RSNA, 2006.

  1. Oh Glorious Geometry: Eclipses, Transits, and Occultations

    NASA Astrophysics Data System (ADS)

    Sinclair, R. M.

    2016-01-01

    Astronomical objects are like a grand clockwork in the sky; they follow steady patterns in time. However, these bright objects we see are not just points of light but have finite dimensions and thus can get in each other's way. As a result, some stars puzzle us by brightening or dimming, or the Sun can frighten us by going out unexpectedly when something else blocks its light. There is nothing unusual about these eclipses, occultations, or transits—they are demonstrations of simple physics—and we take some for granted, like the rotation of Earth moving us into darkness each night. The periodic dimming of a bright star worried mankind for millennia and helped give astronomy a shove. And unexpected events, like a solar or lunar eclipse, can inspire awe and change the course of history. Now that we can observe through telescopes and travel by proxy throughout the solar system, we find the universe is rife with shadow and light shows. Those taking place within our solar system have been useful to astronomy (like the recent transits of Venus or the ever-present eclipses of the Jovian satellites), and were of considerable popular interest, allowing us to think beyond the confines of Earth. Now we detect distant exoplanets transiting their parent stars, announcing the presence of other solar systems in our corner of the Galaxy and changing the discussion about life elsewhere in the universe from mere speculation to plausible possibility. Distant galaxies can make visible ever-further galaxies by forming Einstein rings, allowing us to see behind them and make the structure of the universe more evident. This paper will discuss these phenomena, from those visible easily on Earth to those that can now be seen for the first time from probes in space. We will also discuss how this has expanded popular knowledge of the universe we live in. This paper is illustrated by a number of examples ranging from eclipses and transits throughout the solar system and the nearby stars to

  2. Information retrieval from solar occultation experiments

    NASA Astrophysics Data System (ADS)

    Cox, Helen M.

    Over the past two decades NASA has invested billions of dollars in the development, launch and operation of satellites in a quest to understand and monitor the atmosphere and its changes. As scientists interpret this data with the aid of sophisticated models there is a drive to measure an ever-increasing number of atmospheric properties and constituents. There is however a Emit to the amount of information which can be gained by remote- sensing methods because of the physical nature of these experiments. In this dissertation limitations on the information content of solar occultation experiments, employed to monitor the vertical distribution of stratospheric aerosols and gases for the past twenty years, are evaluated and presented. Solar extinction recorded at wavelengths employed primarily for measuring gas densities inevitably includes a contribution from aerosols, whose spectral scattering behaviour depends on their unknown size distribution. There is a high degree of linear dependence between aerosol extinction measurements at different wavelengths which limits their information content but provides a convenient means for separating aerosol and gas contributions to total measured extinction. Relationships are determined to extract the aerosol contribution from the total extinction at the centres of broadband gas channels. A bias is identified in the current SAGE II aerosol and ozone separation scheme such that under background conditions retrieved ozone concentrations are shown to be biased low by several percent, whereas in post-volcanic periods they are biased high. This shifting bias has introduced an apparent downward trend in SAGE II lower stratospheric ozone concentrations throughout the 1980s as the aerosol size distribution has evolved during a post-volcanic recovery period. Although linear dependence between multi-wavelength aerosol extinction measurements is advantageous for the spectral interpolation of the data, it is detrimental to the recovery of

  3. Occultations of stars by solar system objects. VIII - Occultations of catalog stars by asteroids, planets, Titan, and Triton in 1990 and 1991

    NASA Technical Reports Server (NTRS)

    Wasserman, L. H.; Bowell, E.; Millis, R. L.

    1990-01-01

    Predictions are given for occultations of catalog stars by asteroids, planets, Titan, and Triton in 1990 and 1991. The predictions are based on a computerized comparison of the occulting bodies' ephemerides and nine major star catalogs. The search is complete for all numbered asteroids whose angular diameters exceed 0.08 arcsec during the search years. Preliminary ground tracks are shown for the more favorable occultations.

  4. [Arthroscopically assisted treatment of ankle fractures].

    PubMed

    Braunstein, M; Baumbach, S F; Böcker, W; Mutschler, W; Polzer, H

    2016-02-01

    Acute ankle fractures are one of the most common fractures in adults with an incidence of 0.1-0.2 % per year. Operative treatment by open reduction and internal fixation (ORIF) is the standard method of treatment for unstable or dislocated fractures. The main goal of the operation is the anatomical realignment of the joint and restoration of ankle stability; nevertheless, anatomical reduction does not automatically lead to favorable clinical results. According to several studies the mid-term and in particular the long-term outcome following operative treatment is often poor with residual symptoms including chronic pain, stiffness, recurrent swelling and ankle instability. There is growing evidence that this poor outcome might be related to occult intra-articular injuries involving cartilage and soft tissues. In recent studies the frequency of fracture-related osteochondral lesions was reported to be approximately 64 %. By physical examination, standard radiography or even computed tomography (CT), these intra-articular pathologies cannot be reliably diagnosed; therefore, many authors emphasize the value of ankle arthroscopy in acute fracture treatment as it has become a safe and effective diagnostic and therapeutic procedure. Arthroscopically assisted open reduction and internal fixation (AORIF) allows control of the reduction as well examination of all intra-articular structures. If necessary, intra-articular pathologies can be addressed by removing ruptured ligaments and loose bodies, performing chondroplasty or microfracturing. So far there is no evidence that supplementary ankle arthroscopy increases the complication rate. On the other hand, the positive effect of AORIF has also not been clearly documented; nevertheless, there are clear indications that arthroscopically assisted fracture treatment is beneficial, especially in complex fractures.

  5. The clinical outcome after extra-articular colles fractures with simultaneous moderate scapholunate dissociation.

    PubMed

    Finsen, Vilhjalmur; Rajabi, Benjamin; Rod, Oyvind; Roed, Kristian; Alm-Paulsen, Paal Sandoe; Russwurm, Harald

    2014-05-01

    Background An increased scapholunate gap is sometimes seen in patients with a distal radial fracture. The question remains as to whether this represents a scapholunate ligament injury that requires treatment. Questions/purposes We wished to examine the natural history of an increased scapholunate gap in patients following an extra-articular distal radial fracture. Patients and Methods We reviewed 260 patients who had sustained a distal radial fracture at a mean of 6.2 (2.7-11.9) years previously and identified 12 extra-articular fractures with an increased gap between the lunate and scaphoid. The mean scapholunate gap was 2.6 (2.1-3.4) mm, and the mean scapholunate angle 62° (39°-90°). Controls were found among the remaining patients with extra-articular fractures. Selection criteria were same sex, age at fracture within 5 years, time between injury and review within 2 years, ulnar variance within 2 mm, and dorsal angulation within 5° of index patient. When more than one control fulfilled the criteria for an index patient, their values were averaged. In total there were 54 controls for the 12 index patients. Results The mean difference between index patients and controls in wrist range of motion was 4%, in grip strength 5%, in visual analog scale (VAS) for pain 1 (on a scale from 1 to 100), in Quick-DASH (Disability of the Arm, Shoulder, and Hand) score 5, and in PRWE score 1. The study was calculated to have the power to detect a difference in Quick-DASH scores and in Patient-Rated Wrist Evaluation (PRWE) scores of 14. Conclusions We conclude that at a mean follow up of 6.2 years following an extra-articular distal radial fracture, no surgical treatment is usually needed with a scapholunate gap of between 2.1-3.4 mm. Level of Evidence III, Case control study.

  6. GPS Radio Occultation With Champ: The First Year of The Experiment

    NASA Astrophysics Data System (ADS)

    Wickert, J.; Beyerle, G.; Marquardt, C.; Schmidt, T.; Reigber, Ch.; König, R.; Grunwaldt, L.

    The GPS radio occultation experiment onboard the German CHAMP (CHAllenging Minisatellite Payload) satellite was started on February 11, 2001. During an one hour measurement period seven occultation events were recorded. Already these first mea- surements indicated that in spite of the activated anti-spoofing (A/S) mode of the GPS the state-of-the-art GPS flight receiver combined with favorable antenna characteris- tics allows for global atmosphere sounding with high accuracy and vertical resolution. More than 50,000 occultations are expected as of April 2002. The first year of the CHAMP occultation experiment is reviewed. The occultation infrastructure at the Ge- oForschungsZentrum (GFZ) Potsdam and the operational occultation data processing is characterized. An overview of GFZSs operational data processing, the scientific data analysis and the results of the first year occultation experiment is given. The quality of CHAMPSs occultation data products (vertical atmospheric profiles) is evaluated. Re- sults of data analysis using wave optic methods are presented, e.g. contributions from signals, reflected from EarthSs surface, were found in the occultation data in about 20-30% of the measurements using a radio holographic analysis. Furthermore, the termination of the Selective Availability (SA) mode of the GPS made the application of less-than-double-differencing techniques for GPS occultation analysis feasible. Re- sults of occultation data processing using a space-based single differencing technique are compared with those generated by double differencing as a reference.

  7. The Structure of Enceladus' Plume from Cassini Occultation Observations

    NASA Astrophysics Data System (ADS)

    Hansen, C. J.; Esposito, L. W.; Buffington, B. B.; Colwell, J.; Hendrix, A. R.; Meinke, B. K.; Shemansky, D. E.; Stewart, I.; West, R. A.

    2011-12-01

    Cassini's Ultraviolet Imaging Spectrograph (UVIS) has observed 2 stellar and one solar occultation by Enceladus' water vapor plume. These observations have established that water is the primary constituent of the plume, allowed us to calculate the flux of water coming from the plume, and detected super-sonic jets of gas imbedded within the plume [1]. On 19 October 2011 two stars (epsilon and zeta Orionis) will simultaneously be occulted by the plume, and the signal of the two will be in separate pixels on the detector. This is a tangential occultation that will provide a horizontal cut through the plume at two altitudes. The two stars are separated by 24 mrad, or ~20 km, with the lower altitude star 18 km above the limb at its closest point. The groundtrack is similar to the 2010 solar occultation, but viewed from the other side of the plume. Results from this new data set with implications for the vertical structure of the plume and jets will be presented.

  8. Pluto-Charon Stellar Occultation Candidates: 1990-1995

    NASA Technical Reports Server (NTRS)

    Dunham, E. W.; McDonald, S. W.; Elliot, J. L.

    1991-01-01

    We have carried out a search to identify stars that might be occulted by Pluto or Charon during the period 1990-1995 and part of 1996. This search was made with an unfiltered CCD camera operated in the strip scanning mode, and it reaches an R magnitude of approximately 17.5-about 1.5 mag fainter than previous searches. Circumstances for each of the 162 potential occultations are given, including an approximate R magnitude of the star, which allows estimation of the signal-to-noise ratio (S/N) for observation of each occultation. The faintest stars in our list would yield an S/N of about 20 for a 1 S integration when observed with a CCD detector on an 8 m telescope under a dark sky. Our astrometric precision (+/- 0.2 arcsec, with larger systematic errors possible for individual cases) is insufficient to serve as a final prediction for these potential occultations, but is sufficient to identify stars deserving of further, more accurate, astrometric observations. Statistically, we expect about 32 of these events to be observable somewhere on Earth. The number of events actually observed will be substantially smaller because of clouds and the sparse distribution of large telescopes. Finder charts for each of the 91 stars involved are presented.

  9. Stellar Occultation Studies of Pluto, Triton, Charon, and Chiron

    NASA Technical Reports Server (NTRS)

    Elliot, James L.

    2002-01-01

    Bodies inhabiting the outer solar system are of interest because, due to the colder conditions, they exhibit unique physical processes. Also, some of the lessons learned from them can be applied to understanding what occurred in the outer solar system during its formation and early evolution. The thin atmospheres of Pluto and Triton have structure that is not yet understood, and they have been predicted to undergo cataclysmic seasonal changes. Charon may have an atmosphere - we don't know. Chiron exhibits cometary activity so far from the sun (much further than most comets), so that H2O sublimation cannot be the driving mechanism. Probing these bodies from Earth with a spatial resolution of a few kilometers can be accomplished only with the stellar occultation technique. In this program we find and predict stellar occultation events by small outer-solar system bodies and then attempt observations of the ones that can potentially answer interesting questions. We also develop new methods of data analysis for occultations and secure other observations that are necessary for interpretation of the occultation data.

  10. Occult Dirofilariosis in Dogs of North Eastern Region in India

    PubMed Central

    Borthakur, Sonjoy Kumar; Deka, Dilip Kumar; Islam, Saidul; Sarmah, Prabhat Chandra

    2016-01-01

    Background: The North Eastern Region in India is endemic for canine heartworm disease but in clinics accurate diagnosis is some times difficult. The aim of the present study was to determine the prevalence of occult infections for heartworm disease in canine in two geographical regions of North Eastern India. Methods: A total of 782 numbers of three categories of dogs namely, working dogs of military and paramilitary forces, pet dogs and stray dogs were screened for the presence of heartworm infection from August 2011 to July, 2012 in Guwahati (Assam) and Aizawl (Mizoram). Conventional, immunological and molecular techniques were followed for this epidemiological study. The criteria to determine the occult heartworm cases were based on the differences between heartworm positive cases in PCR test and antigen ELISA test. Results: The findings revealed an overall 22.69 percent occult case. The working dogs had highest prevalence (60%) followed by pet (29.16%) and stray dogs (17.75%). Conclusion: The highest percentage of occult heartworm infection was present in working dogs maintained under military or paramilitary forces. PMID:27047976

  11. Occult hemoglobin as an indicator of impingement stress in fishes

    SciTech Connect

    Not Available

    1980-01-01

    During the process of impingement on cooling system intake screens, fish may be subject to different types of stress, the total of which often results in the death of individual fish. This report assesses the use of occult hemoglobin in fish demand mucus as an indicator of impingement stress. (ACR)

  12. External occulter laboratory demonstrator for the forthcoming formation flying coronagraphs.

    PubMed

    Landini, Federico; Vives, Sébastien; Venet, Mélanie; Romoli, Marco; Guillon, Christophe; Fineschi, Silvano

    2011-12-20

    The design and optimization of the external occulter geometry is one of the most discussed topics among solar coronagraph designers. To improve the performance of future coronagraphs and to stretch their inner fields of view toward the solar limb, the new concept of coronagraphs in formation flight has been introduced in the scientific debate. Solar coronagraphs in formation flight require several mechanical and technological constraints to be met, mainly due to the large dimension of the occulter and to the spacecraft's reciprocal alignment. The occulter edge requires special attention to minimize diffraction while being compatible with the handling and integrating of large delicate space components. Moreover, it is practically impossible to set up a full-scale model for laboratory tests. This article describes the design and laboratory tests on a demonstrator for a coronagraph to be operated in formation flight. The demonstrator is based on the principle of the linear edge, thus the presented results cannot be directly extrapolated to the case of the flying circular occulter. Nevertheless, we are able to confirm the results of other authors investigating on smaller coronagraphs and provide further information on the geometry and tolerances of the optimization system. The described work is one of the results of the ESA STARTIGER program on formation flying coronagraphs ["The STARTIGER's demonstrators: toward a new generation of formation flying solar coronagraphs," in 2010 International Conference on Space Optics (ICSO) (2010), paper 39].

  13. Pluto-Charon stellar occultation candidates - 1990-1995

    NASA Technical Reports Server (NTRS)

    Dunham, E. W.; Mcdonald, S. W.; Elliot, J. L.

    1991-01-01

    A search to identify stars that might be occulted by Pluto or Charon during the period 1990-1995 and part of 1996 is studied. This search was made with an unfiltered CCD camera operated in the strip scanning mode, and it reaches an R magnitude of approximately 17.5 - about 1.5 mag fainter than previous searches. Circumstances for each of the 162 potential occultations are given, including an approximate R magnitude of the star, which allows estimation of the signal-to-noise ratio (S/N) for observation of each occultation. The faintest stars in the list would yield an S/N of about 20 for a 1 s integration when observed with a CCD detector on an 8 m telescope under a dark sky. The astrometric precision (+/- 0.2 arcsec, with larger systematic errors possible for individual cases) is insufficient to serve as a final prediction for these potential occultations, but is sufficient to identify stars deserving of further, more accurate, astrometric observations. Statistically, about 32 of these events to be observable somewhere on earth are expected. The number of events actually observed will be substantially smaller because of clouds and the sparse distribution of large telescopes. Finder charts for each of the 91 stars involved are presented.

  14. Stellar Occultations by Trans-Neptunian Objects and Centaurs

    NASA Astrophysics Data System (ADS)

    Wolf, Juergen

    2015-10-01

    Our solar system beyond Neptune's orbit is populated with numerous small objects, referred to as Trans-Neptunian Objects (TNOs). About 1400 TNOs are known today ranging in size from the most prominent one, Pluto (2370 km diameter), down to a few tens of kilometers. Most diameters have been determined by radiometric methods in the IR/FIR (SPITZER, HERSCHEL) with uncertainties in the 20% range. Only for Pluto and about 12 other objects have the projected diameters been measured more accurately by stellar occultations. A group of objects lingering between the orbits of Jupiter and Neptune, the Centaurs, are believed to have originated from TNOs. Two of them, Chariklo and Chiron, have recently drawn attention, as stellar occultations have revealed rings around them. Our proposed occultation observations with SOFIA shall add to the sparse knowledge on TNOs and Centaurs by determining more projected diameters and albedos. They have the potential of detecting moons, rings and atmospheres. We will use SOFIA's demonstrated capability of measuring occultations (Pluto 2011 & 2015) with its Focal Plane Imager (FPI) to observe up to five events on flight legs of approximately 30 min each. As most of these events cannot be predicted accurately enough more than a few months or weeks ahead of time, we propose these as targets of opportunity.

  15. The Effect of Diurnal Variations on Ionospheric Radio Occultations

    NASA Astrophysics Data System (ADS)

    Yelle, Roger V.; Koskinen, Tommi; Withers, Paul; Schinder, Paul J.; Moses, Julianne I.; Mueller-Wodarg, Ingo

    2016-10-01

    Radio occultations are a powerful technique for the study of atmospheres and ionospheres by planetary spacecraft. For missions to the outer solar system, the occultations always probe the terminator region of the planet. The analysis of radio occultations typically assumes symmetry along the ray path in the horizontal direction about the tangent point. While this is an excellent assumption for the neutral atmosphere where the scale length of horizontal gradients is large, it is suspect for the ionosphere where electron densities decrease rapidly from day to night. Diurnal variations in peak electron density are often several orders of magnitude and may occur over a region of a few degrees. We investigate the consequences of diurnal variations on ionospheric occultations with a ray tracing calculation for the angular deflection and frequency residual of the radio wave. The calculations are based on photochemical/diffusion models for the ionospheres of Saturn and Titan. Differences from analysis based on the assumption of horizontal symmetry are most pronounced in the bottom side ionosphere where chemical time constants are short.

  16. A first demonstration of Mars crosslink occultation measurements

    NASA Astrophysics Data System (ADS)

    Ao, C. O.; Edwards, C. D.; Kahan, D. S.; Pi, X.; Asmar, S. W.; Mannucci, A. J.

    2015-10-01

    A series of three crosslink occultation experiments have been acquired between the Mars Odyssey and Mars Reconnaissance Orbiter spacecraft to probe the Martian atmosphere in 2007. While crosslink occultations between Earth-orbiting satellites have been used to profile the Earth's atmosphere and ionosphere since 1995, this represents the first demonstration of crosslink occultation measurements at another planet. These measurements leverage the proximity link telecommunication payloads on each orbiter, which are nominally used to provide relay communication and navigation services to Mars landers and rovers. Analysis of the observed Doppler shift on each crosslink measurement reveals a clear signature of the Martian atmosphere, primarily the ionosphere. Inversion of the observed Doppler data yields vertical profiles of the Martian refractivity and electron density. The electron density profiles show the presence of two layers with peak densities and peak heights that are consistent with empirical model results. Our study demonstrates the feasibility and future potential of the crosslink radio occultation technique in the exploration of planetary atmospheres.

  17. Sensing Water Vapon via Spacecraft Radio Occultation Observations

    NASA Technical Reports Server (NTRS)

    Kursinski, E. Robert; Hajj, George A.

    2000-01-01

    The radio occultation technique has been used to characterize planetary atmospheres since the 1960's spanning atmospheric pressures from 16 microbars to several bars. In 1988, the use of GPS signals to make occultation observations of Earth's atmosphere was realized by Tom Yunck and Gunnar Lindal at JPL. In the GPS to low-Earth-orbiter limb- viewing occultation geometry, Fresnel diffraction yield a unique combination of high vertical resolution of 100 m to 1 km at long wavelengths (approx. 20 cm) insensitive to particulate scattering which allows routine limb sounding from the lower mesosphere through the troposphere. A single orbiting GPS/GLONASS receiver can observe - 1000 to 1400 daily occultations providing as many daily, high vertical resolution soundings as the present global radiosonde network, but with far more evenly distributed, global coverage. The occultations yield profiles of refractivity as a function of height. In the cold, dry conditions of the upper troposphere and above (T less than 240 K), profiles of density, pressure (geopotential), and temperature can be derived. Given additional temperature information, water vapor can be derived in the midddle and lower troposphere with a unique combination of vertical resolution, global distribution and insensitivity to clouds and precipitation to an accuracy of approx. 0.2 g/kg. At low latitudes, moisture profiles will be accurate to 1-5% within the convective boundary layer and better than 20% below 6 to 7 km. Accuracies of climatological averages should be approx. 0. 1 g/kg limited by the biases in the temperature estimates. To use refractivity to constrain water vapor, knowledge of temperature is required. The simplest approach is to use the temperature field from an analysis such as the 6 hour ECMWF global analysis interpolated to the locations of each occultation. A better approach is to combine the temperature and moisture fields from such an analysis with the occultation refractivity in a weighting

  18. Observational Results from the 2007 March 18 Pluto Stellar Occultation

    NASA Astrophysics Data System (ADS)

    Pasachoff, Jay M.; Babcock, B. A.; Souza, S. P.; McKay, A. J.; Person, M. J.; Elliot, J. L.; Gulbis, A. A.; Zuluaga, C. A.; Hill, J. M.; Ryan, E. V.; Ryan, W. H.

    2007-10-01

    Our consortium observed the 5-minute occultation by Pluto of the star we call P445.3 (2UCAC 25823784, UCAC magnitude 15.3; McDonald and Elliot, 2000, AJ 120, 1599) from sites in the American southwest on 2007 March 17/18 (18 March, UT). Shadow velocity was 6.8 km/s. The 2007 occultation grazed the atmosphere. We were able to use one of the 8.4-m mirrors of the Large Binocular Telescope Observatory, still in its engineering stage, though only with its facility guide camera and not with our Portable Occultation, Eclipse, and Transit System (POETS) CCD/GPS/computer instruments (Souza et al., 2006, PASP 118, 1550). Because of the accurate GPS timing, we were able to align the light curve obtained, which included only the second half of the occultation, with results from other telescopes, including the visible, beamsplit light curve obtained by our group with the 6.5-m MMT (Person et al., 2007, this meeting). We also used, with POETS, the 2.4-m Magdalena Ridge Observatory near Socorro, New Mexico; a partial light curve was obtained despite variable cloudiness throughout the 80 min observation. The location of this telescope was the farthest into the occultation path, and thus led to the deepest incursion into Pluto's atmosphere of the starlight of the major telescopes we used. Light curves were generated by frame-by-frame synthetic-aperture photometry. The large increase in atmospheric pressure we had earlier measured at the 2002 occultation compared with measurements at the first successful Pluto occultation, in 1988, has ceased, as shown by both the 2006 and the current, 2007 measurements. Acknowledgments: We thank Richard Green for granting Director's Discretionary time for the LBT observations. This work was partially funded by NASA Planetary Astronomy grants NNG05GG75G, NNG04GE48G, NNG04GF25G, and NNH04ZSS001N to Williams College and to MIT.

  19. Sensing Water Vapon via Spacecraft Radio Occultation Observations

    NASA Technical Reports Server (NTRS)

    Kursinski, E. Robert; Hajj, George A.

    2000-01-01

    The radio occultation technique has been used to characterize planetary atmospheres since the 1960's spanning atmospheric pressures from 16 microbars to several bars. In 1988, the use of GPS signals to make occultation observations of Earth's atmosphere was realized by Tom Yunck and Gunnar Lindal at JPL. In the GPS to low-Earth-orbiter limb- viewing occultation geometry, Fresnel diffraction yield a unique combination of high vertical resolution of 100 m to 1 km at long wavelengths (approx. 20 cm) insensitive to particulate scattering which allows routine limb sounding from the lower mesosphere through the troposphere. A single orbiting GPS/GLONASS receiver can observe - 1000 to 1400 daily occultations providing as many daily, high vertical resolution soundings as the present global radiosonde network, but with far more evenly distributed, global coverage. The occultations yield profiles of refractivity as a function of height. In the cold, dry conditions of the upper troposphere and above (T less than 240 K), profiles of density, pressure (geopotential), and temperature can be derived. Given additional temperature information, water vapor can be derived in the midddle and lower troposphere with a unique combination of vertical resolution, global distribution and insensitivity to clouds and precipitation to an accuracy of approx. 0.2 g/kg. At low latitudes, moisture profiles will be accurate to 1-5% within the convective boundary layer and better than 20% below 6 to 7 km. Accuracies of climatological averages should be approx. 0. 1 g/kg limited by the biases in the temperature estimates. To use refractivity to constrain water vapor, knowledge of temperature is required. The simplest approach is to use the temperature field from an analysis such as the 6 hour ECMWF global analysis interpolated to the locations of each occultation. A better approach is to combine the temperature and moisture fields from such an analysis with the occultation refractivity in a weighting

  20. Examining Pluto's atmosphere with SOFIA through stellar occultations

    NASA Astrophysics Data System (ADS)

    Person, Michael

    2012-10-01

    We propose to use SOFIA with HIPO, FLITECAM (subject to availability), and the FDC to observe two pairs of Pluto stellar occultations (four total), attempting in each case to observe from the center of Pluto's shadow path. Only an airborne platform such as SOFIA can allow us to directly place the telescope in the shadow paths of these brief events while mitigating the possibility of missing time-sensitive observations due to unfortunate weather systems. Occultation predictions will be updated throughout the period preceding the observations with the goal of achieving sufficient prediction accuracy at the event time to place SOFIA directly in the path of Pluto's central flash. Successful central flash observations will give us unprecedented information regarding Pluto's lower atmospheric structure and global sphericity. The combination of HIPO, FLITECAM, and the FDC will allow us to make simultaneous visible and IR measurements of the occultation light curves in several wavelengths, which are needed to differentiate between two currently competing explanations for the deficiency in the observed light refracted from Pluto's lower atmosphere (strong thermal gradients versus variable particulate extinction). Finally, we propose for two pairs of events in order to investigate the temporal variability of Pluto's atmosphere on several timescales to measure its ongoing evolution due to Pluto's rotation, changing seasonal obliquity (and resulting ice migration), and recession from the sun. These SOFIA observations will all be combined with our ground-based observing program to provide calibrating geometric information to the SOFIA occultation chords, allowing us to precisely pinpoint the actual passage of SOFIA through the occultation shadow path. Given the upcoming New Horizons encounter with the Pluto system in 2015, now is a critical time to provide context and supporting atmospheric information to this NASA mission.

  1. The 2010, February 19 stellar occultation by Varuna

    NASA Astrophysics Data System (ADS)

    Sicardy, Bruno; Colas, F.; Maquet, L.; Vachier, F.; Doressoundiram, A.; Roques, F.; Widemann, T.; Ortiz, J.; Assafin, M.; Braga-Ribas, F.; Camargo, J. I. B.; Vieira-Martins, R.; Andrei, A.; da Silva Neto, D.; Behrend, R.; Hund, F.; Hauser, M.; Wagner, S.; Slotegraaf, A.; Willasch, D.; Costa, M. de Jesus; Melo Sousa, P.; Faustino, E.; Prazeres, A.; Machado, S.; Dias do Nascimento, J.; Souza Barreto, E.; Amorim, A.; da Rocha Poppe, P.; Pereira, M. Geraldete; Jacques, C.; Loureiro Giacchini, B.; Collucci, A.; Ferreira da Costa, W.; Martins de Morais, V.

    2010-10-01

    On 2010, February 19, Varuna occulted UCAC2 star 41014042, as seen from regions in southern Africa and north-eastern Brazil. No occultation was observed neither from the station deployed in South Africa, nor from three other stations in Namibia. Out of twelve stations deployed in Brazil, seven had clouds or instrument malfunctions. Three were negative, one possibly positive (visual) is still being analyzed, and one is definitely positive from Sao Luis (CCD). This makes Varuna the most remote solar system object observed to date through a stellar occultation, with a geocentric distance of 6.4 billions km. The Sao Luis occultation has a duration of 52.5 +/- 0.5 sec, corresponding to a chord length of 1003 +/- 9 km projected in the plane of the sky. No atmospheric signature is apparent in the light curve. Since the closest observation to Sao Luis is negative at a transversal distance of 225 km (Quixada, CCD), a significantly elongated shape is required for Varuna. We will discuss our results in view of current independent estimations of Varuna's diameter combining IR thermal and visible data, with a typical value of 1050 km +/- 200 km (Lellouch et al. 2002, Stansberry et al., 2008). We will also discuss the fact that the occultation occurred near Varuna's maximum brightness along its 6.4 hr rotational (0.4-mag amplitude) light curve. Thus Varuna was observed at maximum apparent surface area, which also corresponds to maximum apparent oblateness for an ellipsoidal shape. Lellouch et al, Astron. Astrophys. 391, 1133-1139 (2002). Stansberry et al., in The Solar System beyond Neptune (eds Barucci, M. A.,Boehnhardt, H., Cruikshank, D. P. & Morbidelli, A.) 161-179 (Univ. Arizona Press, 2008). This work is partially supported by french ANR 08-BLAN-0177 "Beyond Neptune".

  2. OCCULTATION OBSERVATIONS OF SATURN'S B RING AND CASSINI DIVISION

    SciTech Connect

    French, Richard G.; McGhee, Colleen A.; Marouf, Essam A.; Rappaport, Nicole J.

    2010-04-15

    The outer edge of Saturn's B ring is strongly affected by the nearby 2:1 inner Lindblad resonance of Mimas and is distorted approximately into a centered elliptical shape, which at the time of the Voyager 1 and 2 encounters was oriented with its periapse toward Mimas. Subsequent observations have shown that the actual situation is considerably more complex. We present a complete set of historical occultation measurements of the B-ring edge, including the 1980 Voyager 1 and 1981 Voyager 2 radio and stellar occultations, the 1989 occultation of 28 Sgr, two independently analyzed occultations observed with the Hubble Space Telescope in 1991 and 1995, and a series of ring profiles from 12 diametric (ansa-to-ansa) occultations observed in 2005, using the Cassini Radio Science Subsystem (RSS). After making an approximate correction for systematic errors in the reconstructed spacecraft trajectories, we obtain orbit fits to features in the rings with rms residuals well under 1 km, in most cases. Fits to the B-ring edge in the RSS data reveal a systematic variation in the maximum optical depth at the very edge of the ring as a function of its orbital radius. We compare the B-ring measurements to an m = 2 distortion aligned with Mimas, and show that there have been substantial phase shifts over the past 25 years. Finally, we present freely precessing equatorial elliptical models for 16 features in the Cassini Division. The inner edges of the gaps are generally eccentric, whereas the outer edges are nearly circular, with ae < 0.5 km.

  3. Pediatric Thighbone (Femur) Fracture

    MedlinePlus

    ... fractures in infants under 1 year old is child abuse. Child abuse is also a leading cause of thighbone fracture ... contact sports • Being in a motor vehicle accident • Child abuse Types of Femur Fractures (Classification) Femur fractures vary ...

  4. Hydraulic fracturing-1

    SciTech Connect

    Not Available

    1990-01-01

    This book contains papers on hydraulic fracturing. Topics covered include: An overview of recent advances in hydraulic fracturing technology; Containment of massive hydraulic fracture; and Fracturing with a high-strength proppant.

  5. Fracture types (1) (image)

    MedlinePlus

    ... fracture which goes at an angle to the axis Comminuted - a fracture of many relatively small fragments Spiral - a fracture which runs around the axis of the bone Compound - a fracture (also called ...

  6. Galeazzi fracture.

    PubMed

    Atesok, Kivanc I; Jupiter, Jesse B; Weiss, Arnold-Peter C

    2011-10-01

    Galeazzi fracture is a fracture of the radial diaphysis with disruption at the distal radioulnar joint (DRUJ). Typically, the mechanism of injury is forceful axial loading and torsion of the forearm. Diagnosis is established on radiographic evaluation. Underdiagnosis is common because disruption of the ligamentous restraints of the DRUJ may be overlooked. Nonsurgical management with anatomic reduction and immobilization in a long-arm cast has been successful in children. In adults, nonsurgical treatment typically fails because of deforming forces acting on the distal radius and DRUJ. Open reduction and internal fixation is the preferred surgical option. Anatomic reduction and rigid fixation should be followed by intraoperative assessment of the DRUJ. Further intraoperative interventions are based on the reducibility and postreduction stability of the DRUJ. Misdiagnosis or inadequate management of Galeazzi fracture may result in disabling complications, such as DRUJ instability, malunion, limited forearm range of motion, chronic wrist pain, and osteoarthritis.

  7. Recognition of skeletal fractures in infants: an autopsy technique.

    PubMed

    Love, Jennifer C; Sanchez, Luis A

    2009-11-01

    Complete recognition and documentation of injury pattern is crucial in the diagnosis of child abuse. Skeletal fractures regarded as highly specific to nonaccidental injury in infants include posterior rib, scapular, metaphyseal, and spinous process fractures. These injuries are often occult, especially when acute, to standard radiologic and autopsy procedures. The presented autopsy technique requires incising and reflecting skeletal muscles to expose the bones and costal osseous joints in situ, increasing the opportunity to recognize skeletal injury. Fractured or atypical appearing bones are removed and processed for complete evaluation. The bones are processed by macerating the soft tissue in a water soap bath at an elevated temperature. To aid in reconstruction of the decedent, long bones are replaced with wooden dowels and the chest cavity is packed with the organ bag. The technique is invasive and recommended for cases in which the pathologist has reasonable suspicion of acute or remote trauma.

  8. Wave optics-based LEO-LEO radio occultation retrieval

    NASA Astrophysics Data System (ADS)

    Benzon, Hans-Henrik; Høeg, Per

    2016-06-01

    This paper describes the theory for performing retrieval of radio occultations that use probing frequencies in the XK and KM band. Normally, radio occultations use frequencies in the L band, and GPS satellites are used as the transmitting source, and the occultation signals are received by a GPS receiver on board a Low Earth Orbit (LEO) satellite. The technique is based on the Doppler shift imposed, by the atmosphere, on the signal emitted from the GPS satellite. Two LEO satellites are assumed in the occultations discussed in this paper, and the retrieval is also dependent on the decrease in the signal amplitude caused by atmospheric absorption. The radio wave transmitter is placed on one of these satellites, while the receiver is placed on the other LEO satellite. One of the drawbacks of normal GPS-based radio occultations is that external information is needed to calculate some of the atmospheric products such as the correct water vapor content in the atmosphere. These limitations can be overcome when a proper selected range of high-frequency waves are used to probe the atmosphere. Probing frequencies close to the absorption line of water vapor have been included, thus allowing the retrieval of the water vapor content. Selecting the correct probing frequencies would make it possible to retrieve other information such as the content of ozone. The retrieval is performed through a number of processing steps which are based on the Full Spectrum Inversion (FSI) technique. The retrieval chain is therefore a wave optics-based retrieval chain, and it is therefore possible to process measurements that include multipath. In this paper simulated LEO to LEO radio occultations based on five different frequencies are used. The five frequencies are placed in the XK or KM frequency band. This new wave optics-based retrieval chain is used on a number of examples, and the retrieved atmospheric parameters are compared to the parameters from a global European Centre for Medium

  9. Occultation studies of planets and satellites: The occultation of epsilon Geminorum by Mars

    NASA Technical Reports Server (NTRS)

    Elliot, J. L.; Veverka, J.; Sagan, C.

    1977-01-01

    The occultation of epsilon Geminorum by Mars on 1976 April 8 was observed at three wavelengths and 4 ms time resolution with the 91 cm telescope. Temperature, pressure, and number density profiles of the Martian atmosphere were obtained for both the immersion and emersion events. Within the altitude range of 50 to 80 km above the mean surface, the mean temperature is 145 K, and the profiles exhibit wavelike structures with a peak to peak amplitude of 35 K and a vertical scale of about 20 km. The ratio of the refractivity of the atmosphere at 4500 A and 7500 A, determined from the time shift of the light curves for these wavelengths, is consistent with the atmospheric composition measured by Viking 1, 15 weeks later. From the central flash - a bright feature in the light curve midway between immersion and emersion - an optical depth is found at 4500 A of 3.3 plus or minus 1.7 per km atm (about 0.23 per equivalent Martian air mass) for the atmosphere about 25 km above the mean surface, near the south polar region. This large value and its weak wavelength dependence rule out Rayleigh scattering as the principal cause of the observed extinction.

  10. Condylar fractures.

    PubMed

    Sawhney, Raja; Brown, Ryan; Ducic, Yadranko

    2013-10-01

    The purpose of this article is to review the basic indications for different treatments of condylar and subcondylar fractures. It also reviews the steps of different surgical approaches to access the surgical area and explains the pros and cons of each procedure.

  11. Rib Fractures

    MedlinePlus

    ... Brain Damage in Boxers (News) Which High School Sport Has the Most Concussions? Additional Content Medical News Rib Fractures By Thomas ... often... More News News HealthDay Which High School Sport Has the Most Concussions? WEDNESDAY, March 15, 2017 (HealthDay News) -- Female soccer ...

  12. Probing Pluto's Atmosphere Using Ground-Based Stellar Occultations

    NASA Astrophysics Data System (ADS)

    Sicardy, Bruno; Rio de Janeiro Occultation Team, Granada Team, International Occultation and Timing Association, Royal Astronomical Society New Zealand Occultation Section, Lucky Star associated Teams

    2016-10-01

    Over the last three decades, some twenty stellar occultations by Pluto have been monitored from Earth. They occur when the dwarf planet blocks the light from a star for a few minutes as it moves on the sky. Such events led to the hint of a Pluto's atmosphere in 1985, that was fully confirmed during another occultation in 1988, but it was only in 2002 that a new occultation could be recorded. From then on, the dwarf planet started to move in front of the galactic center, which amplified by a large factor the number of events observable per year.Pluto occultations are essentially refractive events during which the stellar rays are bent by the tenuous atmosphere, causing a gradual dimming of the star. This provides the density, pressure and temperature profiles of the atmosphere from a few kilometers above the surface up to about 250 km altitude, corresponding respectively to pressure levels of about 10 and 0.1 μbar. Moreover, the extremely fine spatial resolution (a few km) obtained through this technique allows the detection of atmospheric gravity waves, and permits in principle the detection of hazes, if present.Several aspects make Pluto stellar occultations quite special: first, they are the only way to probe Pluto's atmosphere in detail, as the dwarf planet is far too small on the sky and the atmosphere is far too tenuous to be directly imaged from Earth. Second, they are an excellent example of participative science, as many amateurs have been able to record those events worldwide with valuable scientific returns, in collaboration with professional astronomers. Third, they reveal Pluto's climatic changes on decade-scales and constrain the various seasonal models currently explored.Finally, those observations are fully complementary to space exploration, in particular with the New Horizons (NH) mission. I will show how ground-based occultations helped to better calibrate some NH profiles, and conversely, how NH results provide some key boundary conditions

  13. Advanced Electrocardiography Can Identify Occult Cardiomyopathy in Doberman Pinschers

    NASA Technical Reports Server (NTRS)

    Spiljak, M.; Petric, A. Domanjko; Wilberg, M.; Olsen, L. H.; Stepancic, A.; Schlegel, T. T.; Starc, V.

    2011-01-01

    Recently, multiple advanced resting electrocardiographic (A-ECG) techniques have improved the diagnostic value of short-duration ECG in detection of dilated cardiomyopathy (DCM) in humans. This study investigated whether 12-lead A-ECG recordings could accurately identify the occult phase of DCM in dogs. Short-duration (3-5 min) high-fidelity 12-lead ECG recordings were obtained from 31 privately-owned, clinically healthy Doberman Pinschers (5.4 +/- 1.7 years, 11/20 males/females). Dogs were divided into 2 groups: 1) 19 healthy dogs with normal echocardiographic M-mode measurements: left ventricular internal diameter in diastole (LVIDd . 47mm) and in systole (LVIDs . 38mm) and normal 24-hour ECG recordings (<50 ventricular premature complexes, VPCs); and 2) 12 dogs with occult DCM: 11/12 dogs had increased M-mode measurements (LVIDd . 49mm and/or LVIDs . 40mm) and 5/11 dogs had also >100 VPCs/24h; 1/12 dogs had only abnormal 24-hour ECG recordings (>100 VPCs/24h). ECG recordings were evaluated via custom software programs to calculate multiple parameters of high-frequency (HF) QRS ECG, heart rate variability, QT variability, waveform complexity and 3-D ECG. Student's t-tests determined 19 ECG parameters that were significantly different (P < 0.05) between groups. Principal component factor analysis identified a 5-factor model with 81.4% explained variance. QRS dipolar and non-dipolar voltages, Cornell voltage criteria and QRS waveform residuum were increased significantly (P < 0.05), whereas mean HF QRS amplitude was decreased significantly (P < 0.05) in dogs with occult DCM. For the 5 selected parameters the prediction of occult DCM was performed using a binary logistic regression model with Chi-square tested significance (P < 0.01). ROC analyses showed that the five selected ECG parameters could identify occult ECG with sensitivity 89% and specificity 83%. Results suggest that 12-lead A-ECG might improve diagnostic value of short-duration ECG in earlier detection

  14. Is Occult Obscure Gastrointestinal Bleeding a Definite Indication for Capsule Endoscopy? A Retrospective Analysis of Diagnostic Yield in Patients with Occult versus Overt Bleeding.

    PubMed

    Watari, Ikue; Oka, Shiro; Tanaka, Shinji; Nakano, Makoto; Aoyama, Taiki; Yoshida, Shigeto; Chayama, Kazuaki

    2013-01-01

    Background/Aim. Usefulness of capsule endoscopy (CE) for diagnosing small-bowel lesions in patients with obscure gastrointestinal bleeding (OGIB) has been reported. Most reports have addressed the clinical features of overt OGIB, with few addressing occult OGIB. We aimed to clarify whether occult OGIB is a definite indication for CE. Methods. We retrospectively compared the cases of 102 patients with occult OGIB and 325 patients with overt OGIB, all having undergone CE. The diagnostic yield of CE and identification of various lesion types were determined in cases of occult OGIB versus overt OGIB. Results. There was no significant difference in diagnostic yield between occult and overt OGIB. The small-bowel lesions in cases of occult OGIB were diagnosed as ulcer/erosive lesions (n = 18, 18%), vascular lesions (n = 11, 11%), and tumors (n = 4, 3%), and those in cases of overt OGIB were diagnosed as ulcer/erosive lesions (n = 51, 16%), vascular lesions (n = 31, 10%), and tumors (n = 20, 6%). Conclusion. CE detection rates and CE identification of various small-bowel diseases do not differ between patients with occult versus overt OGIB. CE should be actively performed for patients with either occult or overt OGIB.

  15. Association of preS/S Mutations with Occult Hepatitis B Virus (HBV) Infection in South Korea: Transmission Potential of Distinct Occult HBV Variants

    PubMed Central

    Kim, Hong; Kim, Bum-Joon

    2015-01-01

    Occult hepatitis B virus infection (HBV) is characterized by HBV DNA positivity but HBV surface antigen (HBsAg) negativity. Occult HBV infection is associated with a risk of HBV transmission through blood transfusion, hemodialysis, and liver transplantation. Furthermore, occult HBV infection contributes to the development of cirrhosis and hepatocellular carcinoma. We recently reported the characteristic molecular features of mutations in the preS/S regions among Korean individuals with occult infections caused by HBV genotype C2; the variants of preS and S related to severe liver diseases among chronically infected patients were also responsible for the majority of HBV occult infections. We also reported that HBsAg variants from occult-infected Korean individuals exhibit lower HBsAg secretion capacity but not reduced HBV DNA levels. In addition, these variants exhibit increased ROS-inducing capacity compared with the wild-type strain, linking HBV occult infections to liver cell damage. Taken together, our previous reports suggest the transmission potential of distinct HBV occult infection-related variants in South Korea. PMID:26084041

  16. Anterior superior iliac spine avulsion fracture presenting as meralgia paraesthetica in an adolescent sprinter.

    PubMed

    Hsu, Chia-Yu; Wu, Chu-Ming; Lin, Shih-Wei; Cheng, Kui-Lin

    2014-02-01

    We report here a rare case of anterior superior iliac spine avulsion fracture that presented initially as meralgia paraesthetica. A 14-year-old male sprinter presented with anterior superior iliac spine avulsion fracture, which was not observed on initial plain radiograph of the hip, but was diagnosed by ultrasound. Both clinical presentations and electrophysiological studies indicated meralgia paraesthetica. The lateral femoral cutaneous nerve of the thigh was probably compressed by an inguinal haematoma resulting from sartorius muscle strain, which was detected on musculoskeletal ultrasound. Computed tomography of the pelvis confirmed anterior superior iliac spine avulsion fracture. Meralgia paraesthetica in adolescents can be due to anterior superior iliac spine avulsion fracture. Sonography is a valuable tool for screening for muscular haematoma and occult fractures, which may allow clinicians to diagnose the nature of the muscle injury, and thus guide the most appropriate therapeutic strategy.

  17. The atmosphere of Mars from Mariner 9 radio occultation measurements.

    NASA Technical Reports Server (NTRS)

    Kliore, A. J.; Cain, D. L.; Fjeldbo, G.; Seidel, B. L.; Sykes, M. J.; Rasool, S. I.

    1972-01-01

    Mariner-9 S-band radio occultation measurements conducted during November and December 1971 are described in terms of new information that was obtained about the shape and atmosphere of Mars. The arrival of the spacecraft coincided with a severely obscuring global dust storm, and the effect of the dust in the atmosphere was reflected in the reduced temperature gradients that were measured in the daytime near-equatorial atmosphere, indicating (1) heating of the atmosphere by solar radiation absorbed by dust and (2) simultaneous cooling of the surface. In general, surface atmospheric pressures measured in the equatorial regions are in very good agreement with previous radio-occultation and earth-based measurements. A global disparity in pressures strongly suggests that the physical shape of Mars is more oblate than the shape of its gravitational equipotential surface.

  18. Advancing Technology for Starlight Suppression via an External Occulter

    NASA Technical Reports Server (NTRS)

    Kasdin, N. J.; Spergel, D. N.; Vanderbei, R. J.; Lisman, D.; Shaklan, S.; Thomson, M.; Walkemeyer, P.; Bach, V.; Oakes, E.; Cady, E.; Martin, S.; Marchen, L.; Macintosh, B.; Rudd, R. E.; Mikula, J.; Lynch, D.

    2011-01-01

    External occulters provide the starlight suppression needed for detecting and characterizing exoplanets with a much simpler telescope and instrument than is required for the equivalent performing coronagraph. In this paper we describe progress on our Technology Development for Exoplanet Missions project to design, manufacture, and measure a prototype occulter petal. We focus on the key requirement of manufacturing a precision petal while controlling its shape within precise tolerances. The required tolerances are established by modeling the effect that various mechanical and thermal errors have on scatter in the telescope image plane and by suballocating the allowable contrast degradation between these error sources. We discuss the deployable starshade design, representative error budget, thermal analysis, and prototype manufacturing. We also present our meteorology system and methodology for verifying that the petal shape meets the contrast requirement. Finally, we summarize the progress to date building the prototype petal.

  19. Advancing Technology for Starlight Suppression via an External Occulter

    NASA Technical Reports Server (NTRS)

    Kasdin, N. J.; Spergel, D. N.; Vanderbei, R. J.; Lisman, D.; Shaklan, S.; Thomson, M.; Walkemeyer, P.; Bach, V.; Oakes, E.; Cady, E.; hide

    2011-01-01

    External occulters provide the starlight suppression needed for detecting and characterizing exoplanets with a much simpler telescope and instrument than is required for the equivalent performing coronagraph. In this paper we describe progress on our Technology Development for Exoplanet Missions project to design, manufacture, and measure a prototype occulter petal. We focus on the key requirement of manufacturing a precision petal while controlling its shape within precise tolerances. The required tolerances are established by modeling the effect that various mechanical and thermal errors have on scatter in the telescope image plane and by suballocating the allowable contrast degradation between these error sources. We discuss the deployable starshade design, representative error budget, thermal analysis, and prototype manufacturing. We also present our meteorology system and methodology for verifying that the petal shape meets the contrast requirement. Finally, we summarize the progress to date building the prototype petal.

  20. Digital solar edge tracker for the Halogen Occultation Experiment

    NASA Technical Reports Server (NTRS)

    Mauldin, L. E., III; Moore, A. S.; Stump, C. W.; Mayo, L. S.

    1987-01-01

    The optical and electronic design of the Halogen Occultation Experiment (Haloe) elevation sun sensor is described. The Haloe instrument is a gas-correlation radiometer now being developed at NASA Langley for the Upper Atmosphere Research Satellite. The system uses a Galilean telescope to form a solar image on a linear silicon photodiode array. The array is a self-scanned monolithic CCD. The addresses of both solar edges imaged on the array are used by the control/pointing system to scan the Haloe science instantaneous field of view (IFOV) across the vertical solar diameter during instrument calibration and then to maintain the science IFOV 4 arcmin below the top edge during the science data occultation event. Vertical resolution of 16 arcsec and a radiometric dynamic range of 100 are achieved at the 700-nm operating wavelength. The design provides for loss of individual photodiode elements without loss of angular tracking capability.

  1. Titan's haze as seen by VIMS during solar occultation observations

    NASA Astrophysics Data System (ADS)

    Sotin, Christophe; Lawrence, Ken; Xu, Fang; West, Robert; Brown, Robert; Baines, Kevin; Buratti, Bonnie; Clark, Roger; Micholson, Phil

    2016-06-01

    This study describe solar occultation observations of Titan's atmosphere by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft. These observations include two recent observations made in the last few months. The solar occultation observations have been made at different latitudes and seasons, which allows us to investigate the variability of the density profile of aerosols. We present the line curves in the different atmospheric windows, and the data processing and the inversion method to retrieve vertical density profile. This unique data set provides information on Titan's opacity in the atmospheric windows, which is important to retrieve the surface properties. It also provides information on the cross-subsection of the aerosols as a function of wavelength in the wavelength range 1 to 5 micron.

  2. Radio Occultation Measurements of the Lower Troposphere: A Simulation Study

    NASA Astrophysics Data System (ADS)

    Hurst, K. J.; Ao, C. O.; Mannucci, A. J.

    2011-12-01

    We use simulations to investigate the ability of the Radio Occultation technique to capture the vertical refractivity structure within the Atmospheric Boundary Layer. We first generate a suite of atmospheric profiles of pressure, temperature, water content, and boundary layer height, calculate a suite of forward models to get phase variations which are then run through standard Abel transform-based inversion methods to retrieve the input parameters. We are interested to see if the structure between the bottom and top of the ABL can be resolved in spite of the well known negative bias caused by the large refractivity gradients at the top of the ABL. This study can be used as a basis for comparison with other experimental radio occultation inversion methods.

  3. Status of the Transneptunian Automated Occultation Survey (TAOS II)

    NASA Astrophysics Data System (ADS)

    Reyes-Ruiz, Mauricio

    2014-11-01

    TAOS II is a next generation occultation survey with the goal of measuring the size distribution of the small objects (diameters between 0.5 and 30 km) in the Kuiper Belt. The project is a collaboration between the Academia Sinica Institute of Astronomy and Astrophysics, the Universidad Nacional Autonoma de Mexico, and the Harvard-Smithsonian Center for Astrophysics, The survey will operate three 1.3 m telescopes at San Pedro Martir Observatory in Baja California, Mexico. Each telescope will be equipped with a custom camera comprising a focal plane array of CMOS imagers. Each camera will be capable of reading out image data from 10,000 stars at a cadence of 20 Hz. All telescopes will monitor the same set of stars simultaneously to search for coincident occultation events while minimizing the false positive rate. This poster describes the project and reports on the progress of the development of the survey infrastructure.

  4. ASPIICS: an externally occulted coronagraph for PROBA-3: Design evolution

    NASA Astrophysics Data System (ADS)

    Renotte, Etienne; Baston, Elena Carmen; Bemporad, Alessandro; Capobianco, Gerardo; Cernica, Ileana; Darakchiev, Radoslav; Denis, François; Desselle, Richard; De Vos, Lieve; Fineschi, Silvano; Focardi, Mauro; Górski, Tomasz; Graczyk, Rafał; Halain, Jean-Philippe; Hermans, Aline; Jackson, Carl; Kintziger, Christian; Kosiec, Jacek; Kranitis, Nektarios; Landini, Federico; Lédl, Vít.; Massone, Giuseppe; Mazzoli, Alexandra; Melich, Radek; Mollet, Dominique; Mosdorf, Michał; Nicolini, Gianalfredo; Nicula, Bogdan; Orleański, Piotr; Palau, Marie-Catherine; Pancrazzi, Maurizio; Paschalis, Antonis; Peresty, Radek; Plesseria, Jean-Yves; Rataj, Miroslaw; Romoli, Marco; Thizy, Cédric; Thomé, Michel; Tsinganos, Kanaris; Wodnicki, Ryszard; Walczak, Tomasz; Zhukov, Andrei

    2014-08-01

    PROBA-3 is a mission devoted to the in-orbit demonstration of precise formation flying techniques and technologies for future ESA missions. PROBA-3 will fly ASPIICS (Association de Satellites pour l'Imagerie et l'Interferométrie de la Couronne Solaire) as primary payload, which makes use of the formation flying technique to form a giant coronagraph capable of producing a nearly perfect eclipse allowing to observe the sun corona closer to the rim than ever before. The coronagraph is distributed over two satellites flying in formation (approx. 150m apart). The so called Coronagraph Satellite carries the camera and the so called Occulter Satellite carries the sun occulter disc. This paper is reviewing the design and evolution of the ASPIICS instrument as at the beginning of Phase C/D.

  5. Antarctic Stratospheric Ozone from the Assimilation of Occultation Data

    NASA Technical Reports Server (NTRS)

    Stajner, Ivanka; Wargan, Krzysztof

    2004-01-01

    Ozone data from the solar occultation Polar Ozone and Aerosol Measurement (POAM) III instrument are included in the ozone assimilation system at NASA's Global Modeling and Assimilation Office, which uses Solar Backscatter UItraViolet/2 (SBUV/2) instrument data. Even though POAM data are available at only one latitude in the southern hemisphere on each day, their assimilation leads to more realistic ozone distribution throughout the Antarctic region, especially inside the polar vortex. Impacts of POAM data were evaluated by comparisons of assimilated ozone profiles with independent ozone sondes. Major improvements in ozone representation are seen in the Antarctic lower stratosphere during austral Winter and spring in 1998. Limitations of assimilation of sparse occultation data are illustrated by an example.

  6. Occult otologic fistulas as a cause of recurrent meningitis.

    PubMed

    Mostafa, B E; El Fiky, L; Khafagy, A

    2005-01-01

    Occult perilymph fistulas may be the cause of unexplained non-epidemic meningitis. To review the case reports of 5 patients (3 females and 2 males aged 4-56) presenting with unexplained meningitis. All had sensorineural hearing loss of variable duration. All patients were submitted to CT, MRI and MRI cisternography. All underwent exploratory tympanotomy to seal the fistula. In all patients the fistula could be located and sealed. All had no further attacks of meningitis and those who had serviceable hearing did not show any further deterioration. In any case of recurrent meningitis an occult perilymph leak should be sought. A high degree of suspicion should exist if there are auditory or vestibular symptoms. Detecting and sealing of the defect will protect the patient against further attacks and deterioration of hearing.

  7. New insights to occult gastrointestinal bleeding: From pathophysiology to therapeutics

    PubMed Central

    Sánchez-Capilla, Antonio Damián; De La Torre-Rubio, Paloma; Redondo-Cerezo, Eduardo

    2014-01-01

    Obscure gastrointestinal bleeding is still a clinical challenge for gastroenterologists. The recent development of novel technologies for the diagnosis and treatment of different bleeding causes has allowed a better management of patients, but it also determines the need of a deeper comprehension of pathophysiology and the analysis of local expertise in order to develop a rational management algorithm. Obscure gastrointestinal bleeding can be divided in occult, when a positive occult blood fecal test is the main manifestation, and overt, when external sings of bleeding are visible. In this paper we are going to focus on overt gastrointestinal bleeding, describing the physiopathology of the most usual causes, analyzing the diagnostic procedures available, from the most classical to the novel ones, and establishing a standard algorithm which can be adapted depending on the local expertise or availability. Finally, we will review the main therapeutic options for this complex and not so uncommon clinical problem. PMID:25133028

  8. Digital solar edge tracker for the Halogen Occultation Experiment

    NASA Technical Reports Server (NTRS)

    Mauldin, L. E., III; Moore, A. S.; Stump, C. W.; Mayo, L. S.

    1987-01-01

    The optical and electronic design of the Halogen Occultation Experiment (Haloe) elevation sun sensor is described. The Haloe instrument is a gas-correlation radiometer now being developed at NASA Langley for the Upper Atmosphere Research Satellite. The system uses a Galilean telescope to form a solar image on a linear silicon photodiode array. The array is a self-scanned monolithic CCD. The addresses of both solar edges imaged on the array are used by the control/pointing system to scan the Haloe science instantaneous field of view (IFOV) across the vertical solar diameter during instrument calibration and then to maintain the science IFOV 4 arcmin below the top edge during the science data occultation event. Vertical resolution of 16 arcsec and a radiometric dynamic range of 100 are achieved at the 700-nm operating wavelength. The design provides for loss of individual photodiode elements without loss of angular tracking capability.

  9. Status of the Transneptunian Automated Occultation Survey (TAOS II)

    NASA Astrophysics Data System (ADS)

    Lehner, Matthew J.; Wang, Shiang-Yu; Reyes-Ruiz, Mauricio; Alcock, Charles; Castro, Joel; Chen, Wen-Ping; Chu, You-Hua; Cook, Kem H.; Figueroa, Liliana; Geary, John C.; Huang, Chung-Kai; Kim, Dae-Won; Norton, Timothy; Szentgyorgyi, Andrew; Yen, Wei-Ling; Zhang, Zhi-Wei

    2016-07-01

    The Transneptunian Automated Occultation Survey (TAOS II) will aim to detect occultations of stars by small ( 1 km diameter) objects in the Kuiper Belt and beyond. Such events are very rare (< 10-3 events per star per year) and short in duration ( 200 ms), so many stars must be monitored at a high readout cadence. TAOS II will operate three 1.3 meter telescopes at the Observatorio Astronómico Nacional at San Pedro Mártir in Baja California, México. With a 2.3 square degree field of view and a high speed camera comprising CMOS imagers, the survey will monitor 10,000 stars simultaneously with all three telescopes at a readout cadence of 20 Hz. Construction of the site began in the fall of 2013, and the survey will begin in the summer of 2017.

  10. Status of the Transneptunian Automated Occultation Survey (TAOS II)

    NASA Astrophysics Data System (ADS)

    Lehner, M.; Wang, S.; Zhang, Z.; Ho, P.; Yen, W.; Reyes-Ruiz, M.; Richer, M.; Cook, K.; Hsu, S.; Chen, H.; Chang, Y.; Hiriart, D.; Ricci, D.; Szentgyorgyi, A.; Norton, T.; Geary, J.; Furesz, G.; Alcock, C.; Byun, Y.

    2014-07-01

    The Transneptunian Automated Occultation Survey (TAOS II) will aim to detect occultations of stars by small (˜1 km diameter) objects in the Transneptunian region and beyond. Such events are very rare (<10^{-3} events per star per year) and short in duration (˜200 ms), so many stars must be monitored at a high readout cadence. TAOS II will operate three 1.3 meter telescopes at the Observatorio Astronómico Nacional at San Pedro Mártir in Baja California, México. With a 2.3 square degree field of view and high-speed cameras comprising arrays of custom CMOS imagers, the survey will monitor 10,000 stars simultaneously with all three telescopes at a readout cadence of 20 Hz. The survey will begin operation in 2016. This poster presents an update on the status of the site preparation and the technical development.

  11. Status of the Transneptunian Automated Occultation Survey (TAOS II)

    NASA Astrophysics Data System (ADS)

    Lehner, Matthew; Wang, Shiang-Yu; Alcock, Charles; Reyes-Ruiz, Mauricio; Castro, Joel; Chen, Wen Ping; Chu, You-Hua; Cook, Kem H.; Geary, John C.; Huang, Chung-Kai; Kim, Dae-Won; Norton, Timothy; Szentgyorgyi, Andrew; Yen, WeiLing; Zhang, Zhi-Wei; Figueroa, Liliana

    2016-10-01

    The Transneptunian Automated Occultation Survey (TAOS II) will aim to detect occultations of stars by small (~1 km diameter) objects in the Kuiper Belt and beyond. Such events are very rare ($<0.001 events per star per year) and short in duration (~200 ms), so many stars must be monitored at a high readout cadence. TAOS II will operate three 1.3 meter telescopes at the Observatorio Astronomico Nacional at San Pedro Martir in Baja California, Mexico. With a 2.3 square degree field of view and a high speed camera comprising CMOS imagers, the survey will monitor 10,000 stars simultaneously with all three telescopes at a readout cadence of 20 Hz. Construction of the site began in the fall of 2013, and the survey will begin in the summer of 2017. This poster will provide an update on the status of the survey development and the schedule leading to the beginning of survey operations.

  12. Status of the Transneptunian Automated Occultation Survey (TAOS II)

    NASA Astrophysics Data System (ADS)

    Lehner, Matthew J.; Wang, Shiang Yu; Reyes-Ruiz, Mauricio; Chu, You Hua; Lee, William; Zhang, Zhi Wei; Cook, Kem H.; Norton, Timothy; Szentgyorgyi, Andrew; Alcock, Charles

    2015-11-01

    The Transneptunian Automated Occultation Survey (TAOS II) will aim to detect occultations of stars by small (~1 km diameter) objects in the Kuiper Belt and beyond. Such events are very rare (<10-3 events per star per year) and short in duration (~200 ms), so many stars must be monitored at a high readout cadence. TAOS II will operate three 1.3 meter telescopes at the Observatorio Astronómico Nacional at San Pedro Mártir in Baja California, México. With a 2.3 square degree field of view and a high speed camera comprising CMOS imagers, the survey will monitor 10,000 stars simultaneously with all three telescopes at a nominal readout cadence of 20 Hz. Construction of the site began in the fall of 2013. We present here an update on the status of the TAOS II survey, including the site development, camera fabrication, and project schedule.

  13. Detection of occult disease in tissue donors by routine autopsy.

    PubMed

    Otero, J; Fresno, M F; Escudero, D; Seco, M; González, M; Peces, R

    1998-01-01

    The transmission of infectious and neoplastic diseases is a potential risk of tissue allografting. In this study, we analyzed the occurrence of occult disease in tissue donors as detected by standard screening and autopsy. Whereas 18% of the potential donors initially evaluated were eliminated on the basis of their medical and social histories, laboratory screening and autopsy revealed that an additional 9% of tissue donors had undetected, transmissible disease that prohibited tissue donation. This report emphasizes once again the risk of occult disease being transplanted with grafts and the need for autopsy to reduce the likelihood of this occurring. If donor selection, appropriate screening tests, and autopsy are carefully carried out, the risk of transmitting diseases from tissue allografts can be kept to a minimum.

  14. Analyses for a Modernized GNSS Radio Occultation Receiver

    NASA Astrophysics Data System (ADS)

    Griggs, Erin R.

    Global Navigation Satellite System (GNSS) radio occultation (RO) is a remote sensing technique that exploits existing navigation signals to make global, real-time observations of the Earth's atmosphere. A specialized RO receiver makes measurements of signals originating from a transmitter onboard a GNSS spacecraft near the Earth's horizon. The radio wave is altered during passage through the Earth's atmosphere. The changes in the received signals are translated to the refractivity characteristics of the intervening medium, which enable the calculation of atmospheric pressure, temperature, and humidity. Current satellite missions employing GNSS RO have provided invaluable and timely information for weather and climate applications. Existing constellations of occultation satellites, however, are aging and producing fewer quality measurements. Replacement fleets of RO satellites are imperative to sustain and improve the global coverage and operational impact achieved by the current generation of RO satellites. This dissertation describes studies that facilitate the development of next generation RO receivers and satellite constellations. Multiple research efforts were conducted that aim to improve the quantity and quality of measurements made by a future satellite-based RO collection system. These studies range in magnitude and impact, and begin with a receiver development study using ground-based occultation data. Future RO constellations and collection opportunities were simulated and autonomous occultation prediction and scheduling capabilities were implemented. Finally, a comprehensive study was conducted to characterize the stability of the GNSS atomic frequency standards. Oscillator stability for a subset of satellites in the GNSS was found to be of insufficient quality at timescales relevant to RO collections and would degrade the atmospheric profiling capabilities of an RO system utilizing these signals. Recommendations for a high-rate clock correction network

  15. Pneumonitis associated with occult heartworm disease in dogs.

    PubMed

    Calvert, C A; Losonsky, J M

    1985-05-15

    Nine of 69 dogs with occult heartworm disease (13%) had allergic pneumonitis characterized by consistent clinical and radiographic signs. Although the clinical signs were severe, the degree of radiographic pulmonary arterial abnormalities was mild. Corticosteroid therapy resulted in rapid resolution of clinical and radiographic signs; thiacetarsamide therapy was then given without complications. This syndrome may not be recognized as heartworm-associated and may be confused with other disorders, some being associated with a poor prognosis and requiring different therapy.

  16. Aerosol effects and corrections in the Halogen Occultation experiment

    SciTech Connect

    Hervig, M.E. |; Russell, J.M. III; Park, J.H.

    1995-01-20

    The authors present corrections developed for use with the Halogen Occultation experiment, a shuttle launched mission to measure NO{sub 2}, H{sub 2}O, O{sub 3}, HF, CH{sub 4}, and NO. The system was put in orbit slightly after the eruption of Mt. Pinatubo. If corrections are not factored into the measurements, the increased absorptivity will bias strongly the inferred densities of these trace gases in the stratosphere.

  17. Occult pneumothoraces in patients with penetrating trauma: Does mechanism matter?

    PubMed Central

    Ball, Chad G.; Dente, Christopher J.; Kirkpatrick, Andrew W.; Shah, Amit D.; Rajani, Ravi R.; Wyrzykowski, Amy D.; Vercruysse, Gary A.; Rozycki, Grace S.; Nicholas, Jeffrey M.; Salomone, Jeffrey P.; Feliciano, David V.

    2010-01-01

    Background Supine anteroposterior (AP) chest radiography is an insensitive test for detecting posttraumatic pneumothoraces (PTXs). Computed tomography (CT) often identifies occult pneumothoraces (OPTXs) not diagnosed by chest radiography. All previous literature describes the epidemiology of OPTX in patients with blunt polytrauma. Our goal was to identify the frequency of OPTXs in patients with penetrating trauma. Methods All patients with penetrating trauma admitted over a 10-year period to Grady Memorial Hospital with a PTX were identified. We reviewed patients’ thoracoabdominal CT scans and corresponding chest radiographs. Results Records for 1121 (20%) patients with a PTX (penetrating mechanism) were audited; CT imaging was available for 146 (13%) patients. Of these, 127 (87%) had undergone upright chest radiography. The remainder (19 patients) had a supine AP chest radiograph. Fifteen (79%) of the PTXs detected on supine AP chest radiographs were occult. Only 10 (8%) were occult when an upright chest radiograph was used (p < 0.001). Posttraumatic PTXs were occult on chest radiographs in 17% (25/146) of patients. Fourteen (56%) patients with OPTXs underwent tube thoracostomy, compared with 95% (115/121) of patients with overt PTXs (p < 0.001). Conclusion Up to 17% of all PTXs in patients injured by penetrating mechanisms will be missed by standard trauma chest radiographs. This increases to nearly 80% with supine AP chest radiographs. Upright chest radiography detects 92% of all PTXs and is available to most patients without spinal trauma. The frequency of tube thoracostomy use in patients with overt PTXs is significantly higher than for OPTXs in blunt and penetrating trauma. PMID:20646399

  18. Comparative Structure of Saturn's Rings from Cassini Radio Occultation Observations

    NASA Astrophysics Data System (ADS)

    Marouf, Essam A.; French, R. G.; Rappaport, N. J.; McGhee, C. A.; Wong, K.; Thomson, F. S.; Anabtawi, A.

    2007-10-01

    Radio occultations of Saturn's rings during the Cassini prime mission fall into three main groups, depending on the rings opening angle B. The first is a set of eight diametric occultations completed early in the mission (March-September/2005) when |B| was relatively large (19.5 to 23.5°). They permitted multiple-longitude profiling of relatively optically thick ring features, revealing detailed structure of enigmatic Ring B. The second is to be completed late in the mission when the rings are relatively closed (|B| < 10°). They will provide enhanced sensitivity to tenuous ring material, hence complementary information about small optical depth structure. Bridging the two groups is a third composed of two specially designed occultations recently completed (May-June/2007). They capture the intermediate range |B| 15°. Because the rings were still reasonably open, much of the structure was profiled. The different occultation geometry from the diametric group provided enhanced sensitivity to bending waves and other inclined features. We comparatively consider variability (or lack of) of observed ring structure with B and longitude. The variability when present can be true (dynamically forced features) or apparent (azimuthal asymmetry due to preferentially aligned gravitational wakes). The multiple-longitude coverage provides rich characterization of the true variability, including remarkable variations in the morphology of gap-embedded ringlets in Ring C, clear variations in the width of gaps in the Cassini Division, wavelike features in Ring C (the "Rosen Waves"), classical satellite wake profiles due to Pan, in addition to many density and few bending waves. For the apparent asymmetry, observed optical depth variations with B, viewing geometry, and wavelength constrain physical properties of the rings microstructure (particle sizes, particle-cluster sizes and orientation, spatial cluster density, vertical ring profile and physical thickness, ...). Complementary

  19. Pinhole Occulter Facility. [for X ray observations of sun

    NASA Technical Reports Server (NTRS)

    Dabbs, J. R.; Tandberg-Hanssen, E. A.; Routh, D. E.

    1984-01-01

    The Pinhole Occulter Facility (POF) is designed for X-ray observations of solar activity, coronal structure and solar wind generation, and coronal transients. The four telescopes or positioning counters, the self-deployable 32-m boom, and the pointing-control actuator of the POF are described. The development of the facility is discussed. The configuration of the POF and means of maintaining its attitude control are examined.

  20. Pinhole Occulter Facility. [for X ray observations of sun

    NASA Technical Reports Server (NTRS)

    Dabbs, J. R.; Tandberg-Hanssen, E. A.; Routh, D. E.

    1984-01-01

    The Pinhole Occulter Facility (POF) is designed for X-ray observations of solar activity, coronal structure and solar wind generation, and coronal transients. The four telescopes or positioning counters, the self-deployable 32-m boom, and the pointing-control actuator of the POF are described. The development of the facility is discussed. The configuration of the POF and means of maintaining its attitude control are examined.

  1. The Structure of Titan's Atmosphere from Cassini Radio Occultations

    NASA Technical Reports Server (NTRS)

    Schinder, Paul J.; Flasar, F. Michael; Marouf, Essam A.; French, Richard G.; McGhee, Colleen A.; Kliore, Arvydas J.; Rappaport, Nicole J.; Barbinis, Elias; Fleischman, Don; Anabtawi, Aseel

    2011-01-01

    We present results from the two radio occultations of the Cassini spacecraft by Titan in 2006, which probed mid-southern latitudes. Three of the ingress and egress soundings occurred within a narrow latitude range, 31.34 deg S near the surface, and the fourth at 52.8 deg S. Temperature - altitude profiles for all four occultation soundings are presented, and compared with the results of the Voyager 1 radio occultation (Lindal et al., 1983), the HASI instrument on the Huygens descent probe (Fulchignoni et al., 2005), and Cassini CIRS results (Flasar et al., 2005; Achterberg et al., 2008b). Sources of error in the retrieved temperature - altitude profiles are also discussed, and a major contribution is from spacecraft velocity errors in the reconstructed ephemeris. These can be reduced by using CIRS data at 300 km to make along-track adjustments of the spacecraft timing. The occultation soundings indicate that the temperatures just above the surface at 31-34 deg S are about 93 K, while that at 53 deg S is about 1 K colder. At the tropopause, the temperatures at the lower latitudes are all about 70 K, while the 53 deg S profile is again 1 K colder. The temperature lapse rate in the lowest 2 km for the two ingress (dawn) profiles at 31 and 33 deg S lie along a dry adiabat except within approximately 200m of the surface, where a small stable inversion occurs. This could be explained by turbulent mixing with low viscosity near the surface. The egress profile near 34 deg S shows a more complex structure in the lowest 2 km, while the egress profile at 53 deg S is more stable.

  2. Occult hepatitis C virus infection in Iranian hemodialysis patients

    PubMed Central

    Eslamifar, Ali; Ramezani, Amitis; Ehteram, Hassan; Razeghi, Effat; Ahmadi, Farrokhlagha; Amini, Manouchehr; Banifazl, Mohammad; Etemadi, Gelavizh; Keyvani, Hossein; Bavand, Anahita; Aghakhani, Arezoo

    2015-01-01

    Background: Occult hepatitis C virus (HCV) infection is defined as the presence of HCV-RNA in liver or peripheral blood mononuclear cells (PBMCs) in the absence of detectable hepatitis C antibody (anti-HCV) or HCV-RNA in the serum. Low concentrations of HCV-RNA may be detected in PBMCs of hemodialysis (HD) patients and this could have a great impact on the management of HD patients. Objectives: The aim of this study was to detect the occult HCV infection in Iranian HD patients. Patients and Methods: A total of 70 anti-HCV negative HD patients from three dialysis units in Tehran, Iran were included in this study. In these cases, presence of HCV-RNA in plasma samples was tested by reverse transcriptase-nested polymerase chain reaction (RT-nested PCR). In cases with negative anti-HCV and plasma HCV-RNA, genomic HCV-RNA was checked in PBMC specimens by RT-nested PCR. Results: Seventy anti-HCV negative HD patients were enrolled in the study. 32.85% and 1.43% of cases had elevated levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) respectively. 7.14% of patients had elevated levels of both ALT and AST. HCV-RNA was negative in plasma samples of all anti-HCV negative HD subjects. The genomic HCV-RNA was not detected in any PBMC samples of HD cases with negative anti-HCV and plasma HCV-RNA. Conclusions: Occult HCV infection was not detected in our HD patients despite of elevated levels of liver enzymes in some participants. Further studies involving larger number of HD patients are required to elucidate the rate of occult HCV infection in HD cases. PMID:26457258

  3. Occult persistence and lymphotropism of hepatitis C virus infection

    PubMed Central

    Pham, Tram NQ; Michalak, Tomasz I

    2008-01-01

    Recent discovery of occult hepatitis C virus (HCV) infection persisting after spontaneous or antiviral therapy-induced resolution of hepatitis C was made possible by the introduction of nucleic acid amplification assays capable of detecting HCV RNA at sensitivities superseding those offered by clinical tests. Although individuals with this seemingly silent HCV infection are usually anti-HCV antibody reactive and have normal liver function tests, occult HCV infection has also been reported in anti-HCV-negative individuals with persistently elevated liver enzymes of unknown etiology. Studies have shown that HCV RNA can persist for years in serum, lymphomononuclear cells and liver in the absence of clinical symptoms, although histological evidence of a mild inflammatory liver injury can be occasionally encountered. Furthermore, while HCV RNA can be detected in circulating lymphoid cells in approximately 30% of cases, a short-term culture under stimulatory conditions augments HCV replication in these cells allowing detection of virus in otherwise HCV-negative cases. HCV infects different immune cell subsets, including CD4+ and CD8+ T lymphocytes, B cells and monocytes. Studies employing clonal sequencing and single-stranded conformational polymorphism analyses have revealed unique HCV variants residing in immune cells, further strengthening the notion of HCV lymphotropism. Overall, the data accumulated suggest that occult HCV infection is a common consequence of resolution of symptomatic hepatitis C and that examination of the cells of the immune system is an effective approach to diagnosis of HCV infection and its long-term persistence. Further work is required to fully realize pathogenic and epidemiological consequences of occult HCV persistence. PMID:18473399

  4. Occult HCV Infection: The Current State of Knowledge

    PubMed Central

    Rezaee-Zavareh, Mohammad Saeid; Hadi, Reza; Karimi-Sari, Hamidreza; Hossein Khosravi, Mohammad; Ajudani, Reza; Dolatimehr, Fardin; Ramezani-Binabaj, Mahdi; Miri, Seyyed Mohammad; Alavian, Seyed Moayed

    2015-01-01

    Context Occult HCV infection (OCI) is defined as the presence of HCV-RNA in hepatocytes and the absence of HCV in the serum according to usual tests. We aimed to define OCI and provide information about the currently available diagnostic methods. Then we focus on specific groups that are at high risk of OCI and finally investigate immune responses to OCI and the available treatment approaches. Evidence Acquisition PubMed, Scopus and Google Scholar were comprehensively searched with combination of following keywords: “occult”, “hepatitis C virus” and “occult HCV infection”. The definition of OCI, diagnostic methods, specific groups that are at high risk and available treatment approaches were extract from literature. An analysis of available articles on OCI also was done based on Scopus search results. Results OCI has been reported in several high-risk groups, especially in hemodialysis patients and subjects with cryptogenic liver disease. Furthermore, some studies have proposed a specific immune response for OCI in comparison with chronic hepatitis C (CHC). Conclusions With a clinical history of approximately 11 years, occult HCV infection can be considered an occult type of CHC. Evidences suggest that considering OCI in these high-risk groups seems to be necessary. We suggest that alternative diagnostic tests should be applied and that there is a need for the participation of all countries to determine the epidemiology of this type of HCV infection. Additionally, evaluating OCI in blood transfusion centers and in patients who receive large amounts of blood and clotting factors, such as patients with hemophilia, should be performed in future projects. PMID:26734487

  5. The upper atmosphere of Neptune - An analysis of occultation observations

    NASA Technical Reports Server (NTRS)

    Rages, K.; Veverka, J.; Wasserman, L.; Freeman, K. C.

    1974-01-01

    An analysis of available observations of the April 7, 1968, occultation of BD-17 deg 4388 by Neptune yields upper atmosphere temperatures of about 140 K near the 5 x 10 to the 14th power per cu cm level. The temperature structure of the atmosphere at these levels is complicated and nonisothermal. Diurnal temperature variations are certainly less than 15 K between 0 and 55 deg latitude.

  6. All-Sky Earth Occultation Observations with the Fermi Gamma-Ray Burst Monitor

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, C. A.; Beklen, E.; Bhat, P. N.; Briggs, M.; Camero-Arranz, A.; Case, G.; Jenke, P.; Chaplin, V.; Cherry, M.; Connaughton, V.; Finger, M.; Haynes, R. H.; Preece, R.; Rodi, J.

    2009-01-01

    Using the Gamma Ray Burst Monitor (GBM) on-board Fermi, we are monitoring the hard X-ray/ soft gamma ray sky using the Earth occultation technique. Each time a source in our catalog is occulted by (or exits occultation by) the Earth, we measure its flux using the change in count rates due to the occultation. Currently we are using CTIME data with 8 energy channels spanning 8 keV to 1 MeV for the GBM NaI detectors and spanning 150 keV to 40 MeV for the GBM BGO detectors. Our preliminary catalog consists of galactic X-ray binaries, the Crab Nebula, and active galactic nuclei. In addition, to Earth occultations, we have observed numerous occultations with Fermi's solar panels.

  7. KUIPER BELT OBJECT OCCULTATIONS: EXPECTED RATES, FALSE POSITIVES, AND SURVEY DESIGN

    SciTech Connect

    Bickerton, S. J.; Welch, D. L.; Kavelaars, J. J. E-mail: welch@physics.mcmaster.ca

    2009-05-15

    A novel method of generating artificial scintillation noise is developed and used to evaluate occultation rates and false positive rates for surveys probing the Kuiper Belt with the method of serendipitous stellar occultations. A thorough examination of survey design shows that (1) diffraction-dominated occultations are critically (Nyquist) sampled at a rate of 2 Fsu{sup -1}, corresponding to 40 s{sup -1} for objects at 40 AU, (2) occultation detection rates are maximized when targets are observed at solar opposition, (3) Main Belt asteroids will produce occultations light curves identical to those of Kuiper Belt Objects (KBOs) if target stars are observed at solar elongations of: 116{sup 0} {approx}< {epsilon} {approx}< 125 deg., or 131 deg. {approx}< {epsilon} {approx}< 141 deg., and (4) genuine KBO occultations are likely to be so rare that a detection threshold of {approx}>7-8{sigma} should be adopted to ensure that viable candidate events can be disentangled from false positives.

  8. Lunar occultation observation of μ Sgr: A progress report

    SciTech Connect

    Jatmiko, A. T. P.; Puannandra, G. P.; Hapsari, R. D.; Putri, R. A.; Arifin, Z. M.; Haans, G. K.; Hadiputrawan, I. P. W.

    2014-03-24

    Lunar Occultation (LO) is an event where limb of the Moon passing over a particular heavenly bodies such as stars, asteroids, or planets. In other words, during the event, stars, asteroids and planets are occulted by the Moon. When occulted objects contact the lunar limb, there will be a diffraction fringe(s) which can be measured photometrically, until the signal vanishes into noise. This event will give us a valuable information about binarities (of stars) and/or angular diameters estimation (of stars, planets, asteroids) in milliarcsecond resolution, by fitting with theoretical LO pattern. CCDs are common for LO observation because of its fast read out, and recently are developed for sub-meter class telescope. In this paper, our LO observation attempt of μ Sgr and its progress report are presented. The observation was conducted on July 30{sup th}, 2012 at Bosscha Observatory, Indonesia, using 45cm f/12 GOTO telescope combined with ST-9 XE CCD camera and Bessel B filter. We used drift-scan method to obtain light curve of the star as it was disappearing behind Moon's dark limb. Our goal is to detect binarity (or multiplicity) of this particular object.

  9. First tsunami gravity wave detection in ionospheric radio occultation data

    DOE PAGES

    Coïsson, Pierdavide; Lognonné, Philippe; Walwer, Damian; ...

    2015-05-09

    After the 11 March 2011 earthquake and tsunami off the coast of Tohoku, the ionospheric signature of the displacements induced in the overlying atmosphere has been observed by ground stations in various regions of the Pacific Ocean. We analyze here the data of radio occultation satellites, detecting the tsunami-driven gravity wave for the first time using a fully space-based ionospheric observation system. One satellite of the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) recorded an occultation in the region above the tsunami 2.5 h after the earthquake. The ionosphere was sounded from top to bottom, thus providing themore » vertical structure of the gravity wave excited by the tsunami propagation, observed as oscillations of the ionospheric Total Electron Content (TEC). The observed vertical wavelength was about 50 km, with maximum amplitude exceeding 1 total electron content unit when the occultation reached 200 km height. We compared the observations with synthetic data obtained by summation of the tsunami-coupled gravity normal modes of the Earth/Ocean/atmosphere system, which models the associated motion of the ionosphere plasma. These results provide experimental constraints on the attenuation of the gravity wave with altitude due to atmosphere viscosity, improving the understanding of the propagation of tsunami-driven gravity waves in the upper atmosphere. They demonstrate that the amplitude of the tsunami can be estimated to within 20% by the recorded ionospheric data.« less

  10. First tsunami gravity wave detection in ionospheric radio occultation data

    SciTech Connect

    Coïsson, Pierdavide; Lognonné, Philippe; Walwer, Damian; Rolland, Lucie M.

    2015-05-09

    After the 11 March 2011 earthquake and tsunami off the coast of Tohoku, the ionospheric signature of the displacements induced in the overlying atmosphere has been observed by ground stations in various regions of the Pacific Ocean. We analyze here the data of radio occultation satellites, detecting the tsunami-driven gravity wave for the first time using a fully space-based ionospheric observation system. One satellite of the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) recorded an occultation in the region above the tsunami 2.5 h after the earthquake. The ionosphere was sounded from top to bottom, thus providing the vertical structure of the gravity wave excited by the tsunami propagation, observed as oscillations of the ionospheric Total Electron Content (TEC). The observed vertical wavelength was about 50 km, with maximum amplitude exceeding 1 total electron content unit when the occultation reached 200 km height. We compared the observations with synthetic data obtained by summation of the tsunami-coupled gravity normal modes of the Earth/Ocean/atmosphere system, which models the associated motion of the ionosphere plasma. These results provide experimental constraints on the attenuation of the gravity wave with altitude due to atmosphere viscosity, improving the understanding of the propagation of tsunami-driven gravity waves in the upper atmosphere. They demonstrate that the amplitude of the tsunami can be estimated to within 20% by the recorded ionospheric data.

  11. [Results of conservative treatment in patients with occult pneumothorax].

    PubMed

    Llaquet Bayo, Heura; Montmany Vioque, Sandra; Rebasa, Pere; Navarro Soto, Salvador

    2016-04-01

    An occult pneumothorax is found in 2-15% trauma patients. Observation (without tube thoracostomy) in these patients presents still some controversies in the clinical practice. The objective of the study is to evaluate the efficacy and the adverse effects when observation is performed. A retrospective observational study was undertaken in our center (university hospital level II). Data was obtained from a database with prospective registration. A total of 1087 trauma patients admitted in the intensive care unit from 2006 to 2013 were included. In this period, 126 patients with occult pneumothorax were identified, 73 patients (58%) underwent immediate tube thoracostomy and 53 patients (42%) were observed. Nine patients (12%) failed observation and required tube thoracostomy for pneumothorax progression or hemothorax. No patient developed a tension pneumothorax or experienced another adverse event related to the absence of tube thoracostomy. Of the observed patients 16 were under positive pressure ventilation, in this group 3 patients (19%) failed observation. There were no differences in mortality, hospital length of stay or intensive care length of stay between the observed and non-observed group. Observation is a safe treatment in occult pneumothorax, even in pressure positive ventilated patients. Copyright © 2014 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

  12. Adverse Host Factors Exacerbate Occult HIV-Associated Nephropathy

    PubMed Central

    Kumar, Dileep; Salhan, Divya; Magoon, Sandeep; Torri, Deepti D.; Sayeneni, Swapna; Sagar, Ankita; Bandhlish, Anshu; Malhotra, Ashwani; Chander, Praveen N.; Singhal, Pravin C.

    2011-01-01

    In the present study, we hypothesized that HIV-1–induced occult HIV-associated nephropathy (HIVAN) would become apparent in the presence of adverse host factors. To test our hypothesis, Vpr mice (which display doxycycline-dependent Vpr expression in podocytes) with two, three, and four copies of the angiotensinogen (Agt) gene (Vpr-Agt-2, Vpr-Agt-3, and Vpr-Agt-4) were administered doxycycline for 3 weeks (to develop clinically occult HIVAN) followed by doxycycline-free water during the next 3 weeks. Subsequently, renal biomarkers were measured, and kidneys were harvested for renal histology. Vpr-Agt-2 developed neither proteinuria nor elevated blood pressure, and displayed minimal glomerular and tubular lesions only, without any microcyst formation. Vpr-Agt-3 showed mild glomerular and tubular lesions and microcyst formation, whereas Vpr-Agt-4 showed moderate proteinuria, hypertension, glomerular sclerosis, tubular dilation, microcysts, and expression of epithelial mesenchymal transition markers. Vpr-Agt-4 not only displayed enhanced renal tissue expression of Agt, renin, and angiotensin-converting enzyme, but also had higher renal tissue concentrations of angiotensin II. Moreover, renal cells in Vpr-Agt-4 showed enhanced expression of transforming growth factor-β, connective tissue growth factor, and vascular endothelial growth factor. These findings indicate that adverse host factors, such as the activation of the renin-angiotensin system, promote the progression of occult HIVAN to apparent HIVAN. PMID:21871425

  13. Ionospheric Occultation Experiment (IOX) Data On-Line

    NASA Astrophysics Data System (ADS)

    Chang, B.; Straus, P. R.

    2005-12-01

    The Ionospheric Occultation Experiment (IOX) is a GPS occultation sensor that was part of the US Air Force's Space Test Program PICOSat mission. Launched at the end of September 2001, IOX collected data between November 2001 and October 2004. As opposed to other GPS occultation sensor missions (e.g., GPS-MET, CHAMP, SAC-C) which have a primary focus on tropospheric/stratospheric observations, the IOX mission focus was ionospheric. The PICOSat 67° inclination, 800 km altitude is excellent for performing ionospheric studies because it enables measurements at all local times from an altitude that is almost always above the F-region peak. IOX data can be used to derive total electron content (TEC), electron density profiles, and amplitude and phase scintillation. The complete 3-year IOX database of measurements and data products has been put on-line for general use by the LWS science community. We describe the IOX data products and procedures for utilizing this new resource.

  14. Predictions of Stellar Occultations by Irregular Satellites up to 2020

    NASA Astrophysics Data System (ADS)

    Ramos Gomes, Altair; Assafin, Marcelo; Beauvalet, Laurene; Desmars, Josselin; Vieira-Martins, Roberto; Camargo, Julio I.; Morgado, Bruno Eduardo; Braga Ribas, Felipe

    2017-06-01

    Due to their orbital configurations, it is believed the irregular satellites of the Giant Planets were captured by their host planets during the Solar System evolution. It is important to know their physical parameters such as size, shape, albedo and composition in an attempt to access their origin. The best ground-based technique to do so is by stellar occultations.With the release of the GAIA catalog and the publication of a large database of positions of irregular satellites (Gomes-Júnior et al., 2015), the position of the stars and the ephemeris of the satellites are improved to better predict stellar occultation.The present work predicts such events for the 8 largest irregular satellites of Jupiter and the largest irregular satellite of Saturn, Phoebe, up to 2020. Another motivation is the passage of Jupiter in front of the Galatic Plane in 2019-2020 increasing a lot the number of stars to be occulted. The same happens with Saturn in 2018.

  15. Occult hepatitis B in HIV-HCV coinfected patients.

    PubMed

    Piroth, Lionel; Lafon, Marie-Edith; Binquet, Christine; Bertillon, Pascale; Gervais, Anne; Lootvoet, Enguerrand; Lang, Jean-Marie; De Jaureguiberry, Jean Pierre; Chene, Geneviève; Leport, Catherine

    2008-01-01

    The prevalence of occult hepatitis B infection in HIV infected patients is controversial, varying from less than 1% to 62% in different studies. Blood samples of 111 HIV-infected patients, HCV-positive, HBs antigen negative, followed in the APROCO-ANRS EP11 cohort, were used to detect HBV DNA by using 2 different validated assays (Cobas Amplicor HBV Monitor Test and INSERM U271 qualitative ultra-sensitive PCR), completed when positive by HBV real-time PCR. HBV DNA was found in 6 (5.4%, 95% CI 1.2%-9.6%) patients by at least 1 of these assays, but none tested positive in all 3 assays. All 6 patients had anti-HBc without anti-HBs antibodies; 5 were not on lamivudine. Their median CD4 and CD8 counts were significantly lower and their HIV viral load higher than in the other 105 patients. In conclusion, the prevalence of occult hepatitis B may vary significantly according to the molecular assay used, even though these assays are validated with high specificity and quite high sensitivity. Occult hepatitis B may be encountered in HIV-HCV coinfected patients without anti-HBV treatment, with anti-HBc but without anti-HBs antibodies, and relatively low immunity, suggesting a potential risk of further reactivation, as already sporadically reported.

  16. The 20 March 1980 occultation by the Uranian rings

    NASA Technical Reports Server (NTRS)

    Elliot, J. L.; Frogel, J. A.; Elias, J. H.; Glass, I. S.; French, R. G.; Mink, D. J.; Liller, W.

    1981-01-01

    On March 20, 1980, observations of occultations by rings alpha, beta, gamma, delta, and epsilon were observed from Cerro Tololo and Sutherland. A model ring profile was fit to the data to obtain the midtimes of the occultations and the widths of the profiles. A 14-parameter kinematic model, including J sub 2, J sub 4, and some of the orbital elements for rings 4, alpha, beta, and epsilon as free parameters, was fit to these data and previous ring occultation timings. The results yield J sub 2 = (3.396 + or - 0.020) x 10 to the -3 and a 2 sigma upper limit, absolute value of J sub 4 less than 7 x 10 to the -5th. Uniform precession models for rings alpha, beta are established and the dispersion in the values of semimajor axes and eccentricities for rings alpha, beta, and epsilon have been obtained. If self-gravity is the cause of the uniform precession, the mass of the beta ring is estimated at approximately 4 x 10 to the 16th g; the mass of the alpha ring probably is also near this value.

  17. Facial Fractures

    PubMed Central

    White, Lawrence M.; Marotta, Thomas R.; McLennan, Michael K.; Kassel, Edward E.

    1992-01-01

    Appropriate clinical radiographic investigation, together with an understanding of the normal radiographic anatomy of the facial skeleton, allows for precise delineation of facial fracutres and associated soft tissue injuries encountered in clinical practice. A combination of multiple plain radiographic views and coronal and axial computed tomographic images allow for optimal delineation of fracture patterns. This information is beneficial in the clinical and surgical management patients with facial injuries

  18. Occult hepatitis C virus infection: A new form of hepatitis C

    PubMed Central

    Carreño, Vicente

    2006-01-01

    Occult hepatitis C virus (HCV) infection is a new recently characterized entity. This occult infection can be present in two different clinical situations: in anti-HCV negative, serum HCV-RNA negative patients with abnormal liver function tests and in anti-HCV positive subjects with normal values of liver enzymes and without serum HCV-RNA. This review describes recent studies of occult HCV infection in both kinds of patients. PMID:17109511

  19. Occult hepatitis C virus infection: a new form of hepatitis C.

    PubMed

    Carreño, Vicente

    2006-11-21

    Occult hepatitis C virus (HCV) infection is a new recently characterized entity. This occult infection can be present in two different clinical situations: in anti-HCV negative, serum HCV-RNA negative patients with abnormal liver function tests and in anti-HCV positive subjects with normal values of liver enzymes and without serum HCV-RNA. This review describes recent studies of occult HCV infection in both kinds of patients.

  20. Design of a mirror pointing and occulting mechanism for the Ultraviolet Coronagraph Spectrometer (UVCS)

    NASA Technical Reports Server (NTRS)

    Highman, Clifton O.; Woolaway, Scott M.; Belmont, Kenneth L.

    1992-01-01

    The Mirror and Occulter Mechanism (MOM), a lightweight stable optical assembly which is a critical component to the Ultraviolet Coronagraph Spectrometer to be flown on the European SOHO spacecraft, is discussed. The MOM combines the functions of precision mirror pointing and occultation of stray light into a single package. The mirror mechanism and occulter mechanism designs are described and development testing and life testing activities are discussed.