bluuebunny/crossref_metadata_2025 huggingface dataset:
On some nonlinear inverse problems in elasticity
Authors: Andrieux S. , Bui H.D.
Published: July 2011

In this paper, we make a review of some inverse problems in elasticity, in
statics and dynamics, in acoustics, thermoelasticity and viscoelasticity.
Crack inverse problems have been solved in closed form, by considering a
nonlinear variational equation provided by the reciprocity gap functional.
This equation involves the unknown geometry of the crack and the boundary
data. It results from the symmetry lost between current fields and adjoint
fields which is related to their support. The nonlinear equation is solved
step by step by considering linear inverse problems. The normal to the crack
plane, then the crack plane and finally the geometry of the crack, defined by
the support of the crack displacement discontinuity, are determined
explicitly. We also consider the problem of a volumetric defect viewed as the
perturbation of a material constant in elastic solids which satisfies the
nonlinear Calderon?s equation. The nonlinear problem reduces to two
successive ones: a source inverse problem and a Volterra integral equation of
the first kind. The first problem provides information on the inclusion
geometry. The second one provides the magnitude of the perturbation. The
geometry of the defect in the nonlinear case is obtained in closed form and
compared to the linearized Calderon?s solution. Both geometries, in
linearized and nonlinear cases, are found to be the same.
Thermoinduced plastic flow and shape memory effects
Authors: Xiao Heng , Bruhns Otto , Meyers Albert
Published: July 2011

We propose an enhanced form of thermocoupled J2-flow models of finite
deformation elastoplasticity with temperature-dependent yielding and
hardening behaviour. The thermomechanical constitutive structure of these
models is rendered free and explicit in the rigorous sense of thermodynamic
consistency. Namely, with a free energy function explicitly introduced in
terms of almost any given form of the thermomechanical constitutive
functions, the requirements from the second law are identically fulfilled
with positive internal dissipation. We study the case when a dependence of
yielding and hardening on temperature is given and demonstrate that
thermosensitive yielding with anisotropic hardening may give rise to
appreciable plastic flow either in a process of heating or in a cyclic
process of heating/cooling, thus leading to the findings of one- and two-way
thermoinduced plastic flow. We then show that such theoretical findings turn
out to be the effects found in shape memory materials, such as one- and
two-way memory effects. Thus, shape memory effects may be explained to be
thermoinduced plastic flow resulting from thermosensitive yielding and
hardening behaviour. These and other relevant facts may suggest that, from a
phenomenological standpoint, thermocoupled elastoplastic J2-flow models with
thermosensitive yielding and hardening may furnish natural, straightforward
descriptions of thermomechanical behaviour of shape memory materials.
Role of Intraoperative Varus Stress Test for Lateral Soft Tissue Release during Chevron Bunion Procedure
Authors: Kim Hyong-Nyun , Suh Dong-Hyun , Hwang Pil-Sung , Yu Sun-O , Park Yong-Wook
Published: July 2011

Background:

The purpose of this study was to evaluate the clinical results of distal chevron osteotomy performed in conjunction with selective lateral soft tissue release. The criterion for doing a lateral soft tissue release was assessed by determining the ease and completeness of passive hallux valgus correction at the time of surgery.

Materials and Methods:

Between August 2005 and November 2007, 48 feet in 43 patients classified as having mild to moderate hallux valgus were retrospectively studied. Distal chevron osteotomy without lateral soft tissue release was performed in 26 cases (Group 1) when passive correction of the hallux valgus deformity was possible. Distal chevron osteotomy with lateral soft tissue release was performed in 22 cases (Group 2) when passive correction was not possible. Average followup was 23 (range, 12 to 28) months. Clinical results were assessed using radiographic parameters [hallux valgus angle (HVA), first and second intermetatarsal angle (1,2 IMA)], AOFAS scale and patient's subjective satisfaction.

Results:

For Group 1: the average correction of HVA was 12.8 degrees, the average correction of IMA was 4.7 degrees, and the AOFAS score improved an average of 29.2 points at the last followup. Thirteen patients were very satisfied and ten patients were satisfied with the results. No patient was dissatisfied. For Group 2: the average correction of HVA was 19.1 degrees, the average correction of IMA was 7 degrees and AOFAS score improved at an average of 31.8 points at the last followup. Twelve patients were very satisfied, seven patients were satisfied and one patient, who had stiffness of the first metatarsophalangeal joint, was dissatisfied with the result.

Conclusion:

Distal chevron osteotomy with selective lateral soft tissue release based on the ability to passively correct the hallux valgus deformity lead to safe and stable correction.
Influence of Stretching and Warm-Up on Achilles Tendon Material Properties
Authors: Park Don Young , Rubenson Jonas , Carr Amelia , Mattson James , Besier Thor , Chou Loretta B.
Published: July 2011

Background:

Controversy exists on stretching and warm-up in injury prevention. We hypothesized that warm up has a greater effect on Achilles tendon biomechanics than static stretching. This study investigated static stretching and warm-up on Achilles tendon biomechanics in recreational athletes, in vivo.

Materials and Methods:

Ten active, healthy subjects, 5 males, 5 females, With a mean age of 22.9 years with no previous Achilles tendon injuries were recruited. Typical stretching and warm-up routines were created. Testing was performed in a randomized cross-over design. A custom-built dynamometer was utilized to perform controlled isometric plantarflexion. A low profile ultrasound probe was utilized to visualize the musculotendinous junction of the medial gastrocnemius. An eight-camera motion capture system was used to capture ankle motion. Custom software calculated Achilles tendon biomechanics.

Results:

Achilles tendon force production was consistent. No statistically significant differences were detected in stretch, stiffness, and strain between pre-, post-stretching, and post-warm-up interventions.

Conclusion:

Stretching or warm-up alone, and combined did not demonstrate statistically significant differences. Stretching and warm-up may have an equivalent effect on Achilles tendon biomechanics. Prolonged and more intense protocols may be required for changes to occur.

Clinical Relevance:

Stretching and warm-up of the Achilles before exercise are commonly practiced. Investigating the effect of stretching and warm-up may shed light on potential injury prevention.
Minifragment Plate Fixation of High-Energy Navicular Body Fractures
Authors: Evans Jason , Beingessner Daphne , Agel Julie , Benirschke Stephen K.
Published: July 2011

Background:

The purpose of this study was to assess the ability of miniplate fixation in navicular fractures to restore medial column stability, maintain reduction, and determine the impact this approach may have on the development of avascular collapse of the navicular. We hypothesized that comminuted fractures of the navicular can be safely reduced and maintained to union with minifragment plate fixation with a low incidence of avascular collapse.

Materials and Methods:

A retrospective chart review was performed on 24 patients with navicular fractures treated with open reduction and internal fixation with minifragment plate fixation at a level one trauma center over a period of 6 years.

Results:

All fractures united. No patient developed a deep infection. There was no loss of reduction. Isolated broken screws were evident in three patients (12.5%), with no plate breakage, and no implant failure by pullout. Four patients (17%) underwent plate removal for painful prominent hardware following fracture healing. Four patients (17%) developed radiographic arthrosis of the talonavicular joint. One patient (4%) had radiographic avascular collapse evident at 6 months and was treated with plate removal and an orthotic device.

Conclusion:

Minifragment fixation was a good alternative to independent lag screws for rigid stabilization of navicular body fractures Level of Evidence: IV, Retrospective Case Series
Salvage of Failed Total Ankle Arthroplasty with Fusion Using Structural Allograft and Internal Fixation
Authors: Berkowitz Mark J. , Clare Michael P. , Walling Arthur K. , Sanders Roy
Published: July 2011

Background:

The current study presents our experience with conversion of failed TAA to fusion.

Materials and Methods:

A retrospective review of all failed total ankles converted to fusion from 1999 to 2009 was performed at our institution.

Results:

Twelve total ankles were converted to isolated ankle fusions (Group I) and 12 converted to ankle-hindfoot fusions (Group II). All isolated ankle fusions were stabilized with anterior plate and screws with one nonunion. Structural bone graft was used in ten of 12. Mean outcome scores using the AOFAS-Ankle/Hindfoot score and Maryland Foot Score improved from preoperative values of 43 ± 13 and 56.7 ± 14 to 67 ± 12 and 71.2 ± 16 postoperatively, respectively ( p < 005). All Group II ankle-hindfoot fusion patients were fixed using either anterior plate and screws, intramedullary nail, or a combination nail:plate construct. All received structural allografts. Five patients developed nonunion including four subtalar nonunions Preoperative scores on the AOFAS-AHS and MFS were 48.8 ± 14 and 58.3 ± 14. Postoperative scores were 51.2 ± 17 for the AOFAS and 64.5 ± 14 for the MFS. These changes were not statistically significant. However, the difference in nonunions was significant, p 0.05.

Conclusion:

Failed total ankles can be successfully converted to fusion using structural bone graft and internal fixation. The primary risk appears to be nonunion of the subtalar joint when ankle-hindfoot fusion is required. We believe this risk can be decreased by using a separate approach for preparation of the subtalar joint. Level of Evidence: IV, Retrospective Case Series
Radiographic Evaluation of Minimally Invasive Distal Metatarsal Osteotomy for Hallux Valgus
Authors: Huang Peng-Ju , Lin Yuh-Chuan , Fu Yin-Chih , Yang Yi-Hsin , Cheng Yuh-Min , Cheng Yuh-Min
Published: July 2011

Background:

The use of minimally invasive surgical technique for hallux valgus is controversial. The purpose of this study was to retrospectively evaluate the radiographic results of a minimally invasive distal metatarsal osteotomy for correction of hallux valgus.

Materials and Methods:

From September 2005 to March 2008, a minimally invasive distal metatarsal osteotomy was performed in 82 patients (125 feet) for hallux valgus. The average age was 40.8 (range, 13 to 71) years. The mean followup period was 18.3 (range, 9 to 38) months. These patients were categorized into groups based on their gender, age, preoperative hallux valgus angle, and preoperative 1–2 intermetatarsal angle. The radiographs were reviewed for preoperative and final followup hallux valgus angle, 1–2 intermetatarsal angle, and malunion or nonunion. A final followup hallux valgus angle greater than 20 degrees was defined as “recurrence of deformity” and represented a poor radiographic result.

Results:

There were no nonunions but one case of plantarflexion malunion. One case had skin irritation due to prominent bone. A poor radiographic result occurred in 29 feet (23.2%). Of those 36 feet whose preoperative hallux valgus angle was equal or greater than 30 degrees, 23 feet had a poor radiographic result (63.9%). Of those 89 feet whose preoperative hallux valgus angle was less than 30 degrees, only six feet had a poor radiographic result (6.7%) ( p= 0.0001). The preoperative 1–2 intermetatarsal angle was found to have no statistically significant influence on poor radiographic results ( p = 0.0539). Both the age and sex of the patients had no statistically significant influence ( p = 0.8048 and 0.8604, respectively).

Conclusion:

Based on our results, we do not recommend use of this technique to treat moderate to severe hallux valgus (hallux valgus angle, 30) degrees. We believe a traditional open osteotomy with formal capsulorrhaphy would be a better choice of treatment. Level of Evidence: IV, Retrospective Case Series
Correction of Rigid Equinovarus Deformity Using a Multiplanar External Fixator
Authors: Cuttica Daniel J. , DeCarbo William T. , Philbin Terrence M.
Published: July 2011

Background:

The rigid equinovarus foot deformity is a challenging condition treated by the orthopaedic foot and ankle surgeon. Rapid surgical correction of the deformity may lead to skin and neurologic complications. Gradual correction of the deformity with a multiplanar external fixator may decrease these complications. The purpose of this study was to present the results of a group of patients with rigid equinovarus deformities corrected using a multiplanar external fixator.

Materials and Methods:

We retrospectively reviewed the results of correction of a rigid equinovarus deformity using multiplanar external fixation in a small group of patients. All patients underwent open Achilles lengthening, posterior capsule release, tibialis posterior tendon lengthening, flexor digitorum longus and flexor hallux longus lengthening, followed by application of a multi-planar external fixator with gradual correction of the deformity over a period of several weeks. Preoperative and postoperative deformity and AOFAS ankle-hindfoot scores were assessed.

Results:

A total of eight rigid equinovarus deformities in six patients were treated with a multiplanar external fixator. The average patient age at the time of surgery was 37.2 (range, 17 to 59 ± 15.0) years. Causes of the deformity included trauma in three patients, traumatic brain injury in two patients, and long-standing rheumatoid arthritis in one patient. The average preoperative AOFAS ankle-hindfoot score was 28.3 (range, 12 to 38 ± 7.7). The average postoperative AOFAS ankle-hindfoot score was 68.1 (range 38 to 86 ± 15.5) at an average followup of 71.9 (30 to 120 ± 36.2) weeks. All deformities were gradually corrected to a plantigrade foot using a multiplanar external fixator over an average time of 5 (range, 4 to 6 ± 0.8) weeks. After correction of the deformity, the external fixator was left in place for a time period equal to or twice the length of time it took to achieve correction. The average duration of external fixation was 10.8 (range, 8 to 16 ± 2.8) weeks. Seven of eight deformities maintained correction at final followup. There was one case of recurrence.

Conclusion:

Correction of a rigid equinovarus deformity using a multiplanar external fixator was a viable treatment option. It allowed for correction of the deformity in a controlled manner, helping to reduce the risk of neurovascular complications that may result from single stage surgical correction. The risk of wound complications still exists with the correction of such a complex deformity. Level of Evidence: IV, Retrospective Case Series
Alcohol Sclerosing Therapy is Not an Effective Treatment for Interdigital Neuroma
Authors: Espinosa Norman , Seybold Jeffrey D. , Jankauskas Linas , Erschbamer Matthias
Published: July 2011

Background:

Alcohol sclerosing therapy has been reported as a safe and effective means of treating interdigital neuromas, both with or without ultrasound. The use of ultrasound introduces beside the ultrasound device, increased cost, and the need for skilled technicians and may reduce usability, especially in the outpatient clinic. We report a series of patients with interdigital neuroma treated using ethanol sclerosing therapy in a clinic setting without the use of ultrasound.

Materials and Methods:

We retrospectively reviewed charts of 32 consecutive patients who were enrolled to receive a series of sclerosing ethanol injections from June 2009 to April 2010 for the treatment of a painful interdigital neuroma. Plain radiographs and MRI scans were obtained if clinically indicated to assistance with the diagnosis. Duration and quality of symptoms were recorded and current pain levels were evaluated on a visual analog pain scale. Previous treatments, including orthotic use, corticosteroid injection, or prior neuroma resection were reported. A solution of 1 ml consisting of 20% ethanol and 0.25% bupivacain solution was injected without the use of ultrasound into the affected webspace. The mixture was provided by the local pharmacy. Technical success was confirmed by the temporary resolution of pain following local anesthetic infiltration. If still symptomatic, an injection was repeated every 2 weeks, with most patients receiving a series of four injections. Pain was evaluated on a visual analog pain scale at each visit. Treatment success was defined as resolution of pain as expressed by the patient.

Results:

Of the 32 patients successful relief of symptoms was only achieved in seven patients, while 25 showed no significant reduction of symptoms and considered or underwent a surgical excision.

Conclusion:

Alcohol sclerosing therapy administered in the clinic setting without alcohol is not an effective treatment in the nonoperative management of painful interdigital neuromas and has been abandoned in our clinic. Level of Evidence: IV, Retrospective Case Series
Pantalar Arthrodesis for Post-Traumatic Arthritis and Diabetic Neuroarthropathy of the Ankle and Hindfoot
Authors: Herscovici Dolfi , Sammarco G. James , Sammarco V. James , Scaduto Julia M. , Scaduto Julia M.
Published: July 2011

Background:

Pantalar arthrodesis is an important salvage option for stabilizing the hindfoot and salvaging the limb following trauma or collapse. This report evaluates the healing rates and complications which occur in diabetics and posttraumatic patients.

Materials and Methods:

Twenty patients presenting with post-traumatic arthritis of the ankle-hindfoot (twelve) or with Type II or Type IIIA Charcot arthropathy (eight) were managed with a pantalar fusion. Followup averaged 46 months. Patients were evaluated using the Short Form-36 (SF-36), the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot score, the Short Musculoskeletal Function Assessment (SMFA) and the Visual Analog Pain Scale (VAS).

Results:

There were no amputations in either group. Casting averaged 14.9 weeks, full weightbearing was achieved at 25.1 weeks and time to union averaged 44.1 weeks. Average age was 56.3 yrs. and BMI averaged 34.2. Fourteen patients (70%) had their surgery performed in multiple stages. Acceptable outcomes were noted for all patients for the SF-36, AOFAS and SMFA scores. VAS scores averaged 2.2. There were ten complications (50%); four patients (two in each group) required additional surgery.

Conclusions:

Pantalar arthrodesis is a reasonable salvage option for patients with severe post traumatic arthropathy and neuropathic arthropathy. Patients should be informed of the increased risks as well as the long periods of postoperative immobilization and nonweightbearing. We believe a pantalar arthrodesis can produce acceptable outcomes regardless of the cause of disability, with a staged or single approach, and whether the surgery is performed with plates and screws or an intramedullary device. Level of Evidence: IV, Retrospective Case Series
First Ray Resection Arthroplasty versus Arthrodesis in the Treatment of the Rheumatoid Foot
Authors: Rosenbaum Dieter , Timte Britta , Schmiegel Andreas , Miehlke Rolf K. , Hilker Arvid
Published: July 2011

Background:

Different options exist for the operative treatment of forefoot problems and deformities in rheumatoid arthritis (RA). The current study compared first ray and resection arthroplasty with respect to patient satisfaction, clinical and functional outcome.

Materials and Methods:

In a retrospective study 53 RA patients were investigated with a minimum followup of 2 years after corrective forefoot surgery. Two patient groups were distinguished: One group had been treated with arthrodesis of the first metatarsophalangeal (MTP) joint whereas the other group had been treated with a first ray resection arthroplasty. Both groups underwent resection arthroplasty at the lesser metatarsal heads. Our arthrodesis patients were significantly younger than patients with resection arthroplasty. Five patients had been treated bilaterally so that the results of 58 feet were analyzed.

Results:

Patient satisfaction was lower in the arthrodesis group as compared to the resection arthroplasty patients. However, the arthrodesis patients revealed better functional results and showed a push-off from the hallux. No significant radiographic difference was seen in the mean hallux valgus angles. Younger patients revealed a higher disease activity and a worse general health status than older patients. Pedobaro-graphic results demonstrated significant differences in selected foot regions, predominantly in the hallux. Peak pressures were significantly higher in the lateral midfoot and the hallux after arthrodesis as compared to the resection arthroplasty group.

Conclusion:

Patients with arthrodesis revealed better foot function during the dynamic roll-over process even though the resection arthroplasty patients were subjectively more satisfied. Level of Evidence: Level III, Retrospective Comparative Study
Operative Fixation of Unstable Ankle Fractures in Patients Aged over 80 Years
Authors: Shivarathre Deepak G. , Chandran Prakash , Platt Simon R.
Published: July 2011

Introduction:

Controversy exists regarding the surgical treatment of unstable ankle fractures in the very elderly age group of over 80 years. However, the literature regarding the prognosis of surgery in this elderly group is limited. The purpose of our study was to evaluate the results of patients above 80 years old who underwent operative fixation for unstable ankle fractures.

Materials and Methods:

Ninety-two consecutive patients, 80 females and 12 males, above 80 years of age had open reduction and internal fixation for unstable ankle fractures during the period of January 1998 to August 2007. The data was collected retrospectively from the case records and radiographs. The complications were noted and the risk factors for poor outcome were analyzed. The average age was 85.2 (range, 80.1 to 95.1) years. The minimum duration of followup was 9 months, with an average of 15 (range, 9 to 28) months.

Results:

The most common fracture pattern was Danis-Weber B type. The superficial wound infection rate was 7% (6 cases) and the deep infection rate was 4.6% (4 cases). The 30 day postoperative mortality was 5.4% (five cases). Eighty-six percent (75 out of 87 cases) were able to return back to their pre injury mobility at the last followup. Diabetes, dementia, peripheral vascular disease and smoking were found to be statistically significant risk factors associated with wound complications.

Conclusion:

The results of operative fixation of unstable ankle fractures were encouraging with good functional recovery and return to pre injury mobility status in most cases. Level of Evidence: IV, Retrospective Study
Medial Longitudinal Arch Deformation during Walking and Stair Navigation While Carrying Loads
Authors: Hageman Elizabeth R. , Hall Michelle , Sterner Eric G. , Mirka Gary A.
Published: July 2011

Background:

Understanding the biomechanics of the medial longitudinal arch (MLA) may provide insights into injury risk and prevention, as well as function of the arch-supporting structures. Our understanding of MLA deformation is currently limited to sit-to-stand, walking, and running.

Material and Methods:

Three-dimensional deformation of the MLA of the right foot was characterized in 17 healthy participants during several simulated activities of daily living. MLA deformation was quantified by both changes in arch length and navicular displacement during the stance phase of three motions: walking, stair ascent, and stair descent. Three levels of load were also evaluated: no load, a front load (13.6 kg), and a backpack load (13.6 kg). Force platforms and an eight-camera motion capture system were used to collect relevant lower extremity kinetic and kinematic data.

Results:

Motion type had a significant ( p < 0.05) effect on navicular displacement and arch length elongation with navicular displacement being greatest during stair descent, while the walking and stair descent conditions showed the greatest increase in arch length. External load did not significantly affect either of these two measures ( p > 0.05).

Conclusion:

Differences in the MLA deformation variables resulting from varied dynamic activities of daily living can be greater than those during walking and should be considered.

Clinical Relevance:

Detailing the mechanics of the MLA may aid in further understanding injuries associated with the MLA, and the results of the current study indicate that these mechanics change based on activity.
Freezing Avian Semen
Authors: Blesbois Elisabeth
Published: July 2011

Semen cryopreservation is an important tool for the storage of reproductive cells used for the ex situ management of genetic diversity in birds. Recent advances in poultry semen cryopreservation technology have resulted in the emergence of cryobanking, which is now being developed in an increasing number of countries. In addition, semen freezing methods are now effective for various domestic and wild bird species, although species such as guinea fowls are still highly affected by the process. The methods of freezing avian semen now use a small number of cryoprotectants, (mainly glycerol, dimethyl or N-methylacetamide) and cell packaging (such as straws or pellets). Temperature curves of freezing and thawing remain the most variable points as very slow or very rapid curves are sometimes used in the same species. Specific features of bird reproductive physiology are very important for sperm cryopreservation and application. The characteristics of initial semen quality, including cell membrane properties, mobility capacity and ability to undergo the acrosome reaction are critical points. The specific features of the oviparity system of reproduction and the internal fertilization process affect the conditions of semen use. The in vivo storage of spermatozoa in the sperm storage tubules of the female genital tract, and the conditions of the drastic selection of sperm in the highly specialized female oviduct constitute major factors that are highly species-specific. These constraints involve adaptations of the semen media used for freezing and of the zootechnical parameters of semen use. This review highlights the main factors that are critical for the success of semen cryopreservation in bird species.
An improved transient-type ice-penetrating radar
Authors: Ye Shengbo , Zhou Bin , Wu Bingheng , Zhao Bo , Fang Guangyou
Published: July 2011

A low-cost, compact, short-pulse ice-penetrating radar (IPR) system with a center frequency of 50 MHz for sounding glacier topography is presented. The radar was developed to measure ice thickness and to image internal structures and basal conditions of glaciers and ice sheets with a maximum range of ∼16000 ns and a depth resolution better than 2.5 m. The receiver of the IPR system employs asynchronous operation mode, avoiding the need for a cable between the transmitter and receiver. A new sampling technology using a high-speed field programmable gate array, which implements a 256-trace stacking algorithm to realize the analog-to-digital conversion, both simplifies the structure of the receiver and increases the sampling efficiency. The power consumption of the whole receiver is <1.5 W, which can be supplied by a laptop computer. Test measurements were made during the 5th China Expedition to the Grove Mountains in East Antarctica. Field tests show the capability of this system to measure ice thickness up to 650 m and to define internal layers within the ice body.
In situ measurements of firn compaction profiles using borehole optical stratigraphy
Authors: Hawley Robert L. , Waddington Edwin D.
Published: July 2011

We have developed a technique in which we use a borehole video camera and post-processing software to make a record of the optical brightness as a function of depth in polar firn. We call this method borehole optical stratigraphy. To measure firn compaction, we note the positions of optical features on the borehole wall detected by an initial ‘baseline’ log. We track the displacements of these features in subsequent logs. The result provides a measurement of the relative vertical motion and thus compaction of the firn over the survey period. We have successfully used this system at Summit, Greenland, to measure the depth distribution of firn column shortening experienced in a borehole over three 1 year periods. The uppermost 30 m of the firn at Summit is compacting as predicted by a simple steady-state model, implying that the firn density profile at Summit is at or close to steady state over the past ∼70 years.
Glacier hydromechanics: early insights and the lasting legacy of three works by Iken and colleagues
Authors: Flowers Gwenn E.
Published: July 2011

The association between basal hydrology and glacier sliding has become nearly synonymous with the early work of Almut Iken and colleagues. Their research published in theJournal of Glaciologyfrom 1981 to 1986 made an indelible impact on the study of glacier hydromechanics by documenting strong correlations between basal water pressure and short-term ice-flow variations. With a passion for elucidating the physics of glacier-bed processes, Iken herself made fundamental contributions to our theoretical and empirical understanding of the sliding process. From the theoretical bound on basal shear stress, to the inferences drawn from detailed horizontal and vertical velocity measurements, the work of Iken and colleagues continues to inform the interpretation of data from alpine glaciers and has found increasing relevance to observations from the ice sheets.
Weertman, Lliboutry and the development of sliding theory
Authors: Fowler A.C.
Published: July 2011

This paper reviews the seminal contributions (and tussles) of Weertman and Lliboutry to the theory of glacier sliding in the 1950s and 1960s, and summarizes later developments up to the present day.
Understanding ice-sheet mass balance: progress in satellite altimetry and gravimetry
Authors: Pritchard H.D. , Luthcke S.B. , Fleming A.H.
Published: July 2011

Satellite remote sensing has come to dominate the measurement of glacier and ice-sheet change. Three independent methods now exist for assessing ice-sheet mass balance and we focus on progress in two: satellite altimetry (ICESat) and gravimetry (GRACE). With improved spatial and temporal sampling, and synergy with ice flow measurements, both the mechanisms and causes changing mass balance can be investigated. We present examples of mass losses due to widespread, intensifying glacier dynamic thinning in northwest Greenland, but local ablation rates in the northeast that are unchanged for decades. Advances in GRACE processing reveal Greenland net ice-sheet mass loss continuing into 2010, at 195 ± 30 Gta-1. A similarly negative trend in the Gulf of Alaska has significant spatial and temporal variation, that highlights the importance of intense summer melting here. Strong summer melt on the Antarctic Peninsula also precipitated recent ice-shelf collapse and prompted rapid dynamic thinning of tributary glaciers at up to 70 m a-1. Thinning continued for years to decades after collapse and propagated far inland. While understanding of the physical mechanisms of change continues to improve, estimates of future behaviour, and in particular the near-future glacial sea-level contribution, still rely on projections from such observations. We introduce the suite of new sensors that will monitor the ice sheets into the future.
Women in glaciology, a historical perspective
Authors: Hulbe Christina L. , Wang Weili , Ommanney Simon
Published: July 2011

Women’s history in glaciology extends as far back in time as the discipline itself, although their contributions to the scientific discourse have for all of that history been constrained by the sociopolitical contexts of the times. The firstJournal of Glaciologypaper authored by a woman appeared in 1948, within a year of the founding of theJournal, but it was not until the 1980s that women produced more than a few percent ofJournalandAnnals of Glaciologypapers. Here international perspectives on women’s participation in the sciences are presented in order to establish an economic and sociopolitical context for stories of women ‘pioneers’ in glaciology and a frame in which to discuss women’s persistent under-representation relative to men. We find that the experiences of individual glaciologists mirror women’s experiences in higher education and the sciences as a whole. The existence of both positive and negative trends in women’s participation in the sciences suggests caution in the interpretation of recent positive trends for women’s participation in glaciology.
The Journal of Glaciology: its origin and early history
Authors: Glen John W.
Published: July 2011

This paper records the history of how and why the Journal of Glaciology was started and how it has grown into the Journal we know today.
Influence of Climatic Changes on Pollution Levels in Hungary and Surrounding Countries
Authors: Zlatev Zahari , Havasi Ágnes , Faragó István
Published: July 2011

The influence of future climatic changes on some high pollution levels that can cause damage to plants and human beings is studied in this paper. The particular area of interest is Hungary and its surrounding countries. Three important quantities, which are closely related to ozone concentrations, have been investigated. We shall mainly focus on cases where the critical values, prescribed in the directives, are exceeded. Six scenarios, which allow us to compare directly the future and the present levels, have been run over a period of sixteen years. Some of the results obtained in the selected domain by using these scenarios have been carefully studied. The major conclusion is that an increase in temperature in combination with some other factors might lead to rather considerable increases of the damaging effects of ozone on plants and humans.
Enhanced Chiral Recognition by Cyclodextrin Dimers
Authors: Voskuhl Jens , Schaepe Kira , Ravoo Bart Jan
Published: July 2011

In this article we investigate the effect of multivalency in chiral recognition. To this end, we measured the host-guest interaction of a β-cyclodextrin dimer with divalent chiral guests. We report the synthesis of carbohydrate-based water soluble chiral guests functionalized with two borneol, menthol, or isopinocampheol units in either (+) or (–) configuration. We determined the interaction of these divalent guests with a β-cyclodextrin dimer using isothermal titration calorimetry. It was found that—in spite of a highly unfavorable conformation—the cyclodextrin dimer binds to guest dimers with an increased enantioselectivity, which clearly reflects the effect of multivalency.
Boronization and Carburization of Superplastic Stainless Steel and Titanium-Based Alloys
Authors: Matsushita Masafumi
Published: July 2011

Bronization and carburization of fine-grain superplastic stainless steel is reviewed, and new experimental results for fine grain Ti88.5Al4.5V3Fe2Mo2 are reported. In superplastic duplex stainless steel, the diffusion of carbon and boron is faster than in non-superplastic duplex stainless steel. Further, diffusion is activated by uniaxial compressive stress. Moreover, non-superplastic duplex stainless steel shows typical grain boundary diffusion; however, inner grain diffusion is confirmed in superplastic stainless steel. The presence of Fe and Cr carbides or borides is confirmed by X-ray diffraction, which indicates that the diffused carbon and boron react with the Fe and Cr in superplastic stainless steel. The Vickers hardness of the carburized and boronized layers is similar to that achieved with other surface treatments such as electro-deposition. Diffusion of boron into the superplastic Ti88.5Al4.5V3Fe2Mo2 alloy was investigated. The hardness of the surface exposed to boron powder can be increased by annealing above the superplastic temperature. However, the Vickers hardness is lower than that of Ti boride.
Three New Phytoecdysteroids Containing a Furan Ring from the Roots of Achyranthes bidentata Bl.
Authors: Wang Qiu-Hong , Yang Liu , Jiang Hai , Wang Zhi-Bin , Yang Bing-You , Kuang Hai-Xue
Published: July 2011

Three new phytoecdysteroid compounds, named niuxixinsterone A (1), B (2) and C (3) with acetal functions in the side-chain were isolated from Achyranthes bidentata Bl. The structures were established as (20R,22R,24S)-20-O,22-O-(5′-hydroxymethyl)-furfurylidene-2β,3β,14α,25-tetrahydroxy-5β-ergost-7-en-6-one (1), (20R,22R)-20-O,22-O-(5′-hydroxymethyl)-furfurylidene-2β,3β,25-trihydroxy-14β-methyl-18-nor-5β-cholesta-7,12-dien-6-one (2) and (20R,22R,25R)-20-O,22-O-(5′-hydroxymethyl)-furfurylidene-2β, 3β,5β,14α,26-pentahydroxycholest-7-en-6-one (3) by means of spectroscopic evidence.
Transmission des connaissances dans les relations de coopération inter-entreprises : TIC versus face à face
Authors: Aguilera Anne , Lethiais Virginie
Published: July 2011

L’usage des TIC est régulièrement envisagé comme pouvant favoriser une réduction des besoins de mobilité physique. Cette recherche vise à identifier et hiérarchiser les facteurs qui influencent la fréquence relative des rencontres face à face dans les relations de coopération inter-entreprises. Une analyse économétrique, basée sur une enquête auprès de 348 entreprises bretonnes, nous permet de confirmer l’existence d’une relation positive entre le besoin de partager des informations tacites et les rencontres face à face. Nous montrons aussi que la capacité à codifier les échanges, la distance géographique entre les partenaires, le nombre des relations de coopération et l’appropriation d’Internet dans l’entreprise contribuent à réduire le recours à la mobilité.
Diffusion et production des connaissances : les deux faces d'une action territoriale réussie
Authors: Forest Joëlle , Serrate Bénédicte
Published: July 2011

Si la spatialisation des dynamiques d’innovation est étudiée depuis longtemps par l’économie régionale, l’axe central de ces recherches concerne la diffusion des connaissances, i.e. les conditions d’accessibilité et d’appropriation aux connaissances. L’idée principale présentée dans cet article est qu’il est cependant nécessaire que les clusters d’innovation, en tant qu’instrument de la politique d’innovation, ne se focalisent pas de manière exclusive sur la diffusion des connaissances nécessaire à l’innovation, mais aussi sur leur production. La production de connaissances ayant été vérifiée empiriquement à partir de deux études de cas exploratoires et d’une étude quantitative auprès de firmes innovantes de la région Rhône-Alpes, l’article suggère que la question de la production doit être prise à bras le corps pour garantir le développement, à l’échelle d’un territoire donné, d’une capacité effective à innover.
Childhood Orbitotemporal Neurofibromatosis Masked by Congenital Glaucoma and Buphthalmos
Authors: Ziakas Nikolas G. , Kanonidou Evgenia D. , Boboridis Kostas G.
Published: July 2011

In newborns with unilateral buphthalmos and presumed congenital glaucoma, the differential diagnosis should include the rare condition of orbitotemporal neurofibromatosis. The authors present the diagnostic challenge of an unusual case of neurofibromatosis type 1 with unilateral congenital glaucoma, buphthalmos, and sphenoid-orbital dysplasia. The accompanying type of osseous orbital dysplasia has rarely been described in the literature, complicating the diagnostic and management process.
Relational Agents as an Adjunct in Schizophrenia Treatment
Authors: Puskar Kathryn , Schlenk Elizabeth A. , Callan Judith , Bickmore Timothy , Sereika Susan
Published: July 2011

The purpose of this article is to discuss medication nonadherence and the use of relational agent technology as an aid in treating patients with schizophrenia. A team of mental health faculty—specialists in adherence, computer science, and statistics—collaborated to design the agent technology. This computerized virtual health counselor named “Laura” provides seven education modules about schizophrenia. Using preliminary data, two individual examples demonstrate the use of this technology. Implications for behavioral health nurses using this relational agent technology as an adjunct in improving mental health care are discussed.
Psychoactive Herb Use and Youth: A Closer Look at Salvia Divinorum
Authors: Ahern Nancy R. , Greenberg Cindy S.
Published: July 2011

Salvia divinorum
is a psychoactive herb and an increasingly popular recreational drug used by young people in our country and abroad. Much of its increased popularity stems from its easy accessibility and affordability; its effects produce an intense and potent “high” and concomitant disorientation and hallucinations. The risks associated with Salvia are poorly defined due to a lack of scientific evidence, leaving Salvia users with false assurances about its safety. Although its safety profile is ill defined, its intense effects are well known and can put young people at risk for injuries and serious errors in judgment. Psychiatric nurses and health care practitioners are in key positions to influence practice, education, and policy regarding the use and abuse of this drug by youth.
Risk factors for third- and fourth-degree perineal tears during vaginal delivery
Authors: Juul Leonard , Theron Gerhard B.
Published: July 2011

Objective. To identify risk factors for thirdand fourth-degree perineal tears, so as to anticipate and intervene in order to prevent this complication that can severely affect a woman’s quality of life. The study design was a retrospective case control study. Method. Ninety-three cases of third- and fourth-degree perineal tears were identified from the birth register of a tertiary referral hospital (Tygerberg Hospital). One hundred and nine patients with normal vaginal deliveries in the same time period were used as control group. Results. An analysis of the results revealed that there were no significant differences between cases and controls with regards to age, body mass index (BMI), gestation at delivery, duration of second stage, episiotomy and birth weight. However, there were significantly more primigravidas, assisted deliveries (forceps and vacuum), occipitoposterior positions, HIV negative patients and shoulder dystocia in the study group. Conclusions. Antenatal risk factors for thirdand fourth-degree tears are difficult to identify. However, intrapartum occipitoposterior and assisted deliveries, especially in the primigravid patient, should warn the obstetrician/ midwife about the risk of a severe tear. A restrictive episiotomy policy should be practiced. Shoulder dystocia was invariably associated with third- and fourth-degree tears in this study. The higher incidence of HIV negative patients in the study group requires further research.
Low-count bacteriuria in refractory idiopathic detrusor overactivity versus controls
Authors: Walsh Colin , Allen Wendy , Parkin Katrina , Mukerjee Chinmoy , Moore Kate
Published: July 2011

Background. Previous studies suggest an association between idiopathic detrusor overactivity (IDO) and high-count bacteriuria (>105 CFU/mL). Recently, the importance of low-count bacteriuria (103–105 CFU/mL) in dysuric women with has been recognised. However, the optimal microbiological threshold for women with overactive bladder (OAB) symptoms remains unclear. Design and Methods A 2-year prospective cohort study, to examine the incidence of low-count and high-count bacteriuria in women with refractory IDO (RIDO) versus a control group without OAB symptoms. Women with dysuria, voiding dysfunction or recent urethral instrumentation were excluded. Mid-stream urine (MSU) specimens were collected during acute symptomatic exacerbation in the IDO group and cultured at the 103 CFU/mL threshold. Statistical analysis was performed using Statsdirect statistical package 2.7.2. Results. Between November 2007 and November 2009, 218 study MSU specimens were collected. Both the overall incidence of any significant bacteriuria ≥103 CFU/mL (P<0.0001) and the incidence of low-count bacteriuria (P=0.0091) were significantly higher in the RIDO women than the controls. There were no baseline differences in age, menopausal status or prior continence surgery between the groups. In the RIDO group, specimens positive for low-count bacteriuria only were less likely to be associated with significant pyuria P<0.0001) and were cultured from younger women (P=0.0009), than specimens positive for high-count bacteriuria. Conclusions The prevalence of bacteriuria in women with RIDO during symptomatic exacerbation is 40%, which is significantly higher than the incidence in similarly-aged women without OAB. One-third of positive cultures show low-count bacteriuria only. The management of women with RIDO should include a search for bacteriuria, including low-count bacteriuria.
O colecionismo bibliográfico: uma abordagem do livro para além da informação
Authors: Murguia Eduardo Ismael
Published: July 2011

O presente artigo pretende refletir sobre um tema esquecido pela Biblioteconomia: a formação de coleções bibliográficas. Desde o inicio da Ciência da Informação, a ênfase foi colocada na informação, passando o suporte e a materialidade do livro a um segundo plano. Com a finalidade de iniciar uma discussão que resgate o suporte da informação, foi proposto o conceito de semióforo como meio de salvar a divisão material/imaterial. Assim, num primeiro momento apresenta-se uma discussão bibliográfica que introduz os conceitos de Cultura material e de Colecionismo em diferentes áreas. Em seguida, centraliza-se a argumentação no campo da Biblioteconomia, na sua relação com o colecionismo bibliográfico, destacando-se a Bibliofilia. Por último, na justificativa, resgata-se o título do trabalho para apontar a necessidade dos estudos de colecionismo na área, propondo-se a utilização do conceito de semióforo, não unicamente como ferramenta que supere a divisão suporte/texto, mas como um conceito que oferece subsídios teóricos para o entendimento do problema; para assim chegar ao objetivo específico da pesquisa: discutir que, na sua condição de semióforo, o objeto livro possui características específicas (subjetivas e materiais) que fazem com que o sujeito estabeleça relações outras do que a simples busca de informação e criação de conhecimento.
Collateral Tissue Damage by Several Types of Coagulation (Monopolar, Bipolar, Cold Plasma and Ultrasonic) in a Minimally Invasive, Perfused Liver Model
Authors: Carus Thomas , Rackebrandt Klaas
Published: July 2011

Hemostasis in minimally invasive surgery causes tissue damage. Regardless of the method of production of thermal energy, a quick and safe coagulation is essential for its clinical use. In this study we examined the tissue damage in the isolated perfused pig liver using monopolar, bipolar, cold plasma, and ultrasonic coagulation. In a minimally invasive in vitro setup, a 2-3 cm slice of the edge of the perfused pig liver was resected. After hemostasis was achieved, liver tissue of the coagulated area was given to histopathological examination. The depth of tissue necrosis, the height of tissue loss, and the time until sufficient hemostasis was reached were analyzed. The lowest risk for extensive tissue damage could be shown for the bipolar technique, combined with the highest efficiency in hemostasis. Using cold plasma, coagulation time was longer with a deeper tissue damage. Monopolar technique showed the worst results with the highest tissue damage and a long coagulation time. Ultrasonic coagulation was not useful for coagulation of large bleeding areas. In summary, bipolar technique led to less tissue damage and best coagulation results in our minimally invasive model. These results could be important to recommend bipolar coagulation for clinical use in minimally invasive surgery.