bluuebunny/crossref_metadata_2025 huggingface dataset:
Accuracy of Robotic Guidances in Transpedicular Spinal Screw Placement: A Series of 93 Patients for the First Time in Vietnam
Authors: Le Bao Tien Nguyen , Van Thach Nguyen , Dinh Hoa Nguyen
Published: April 2016

Introduction

The Renaissance Robotic System is a technology used to guide screw placement through thoracic and lumbar spinal pedicle with high accuracy. This research introduces evaluation of the first series of 93 patients used this system in Vietnam for further evaluating the accuracy of the robotic guidance system for spinal surgery.

Material and Methods

Patients underwent spinal surgery using pedicle screws placement are main subjects of this research. Total 93 patients were divided into 2 groups (MIS group and classic procedure group). Among each group, the first 10 cases were studied and compared with the remaining cases. The accuracy of 1003 pedicle screws inserted in 93 patients was measured via postoperative CT scans system. The result based on the position of screw was evaluated in 3 aspects: axial, lateral and A-P.

Results

93 patients under this research include 6 patients of trauma case, 29 patients of scoliosis case, 58 patients of spondylolisthesis case. Measurements derived from postoperative CT scans demonstrated the fact that 98.3% of the screws fell within the safe zone (Group A and B), where 90.3% were completely within the pedicle (Gertbein and Robbins classification). The MIS procedure was performed on 33 patients. Among these 33 patients, there appeared a significantly different accuracy between the first ten patients to the remaining of each group (accuracy change from 80% of Group A to 95.7% of Group B, p = 0.05). Among patients group underwent the classic procedure, the accuracy between the first ten patients to the remaining of the group also showed significant difference (accuracy changed from 96.5% of Group A to 99.3% of Group B, p = 0.05). 7/1003 pedicle screws were reinserted by free hand technique. On axial aspect, 915 (91.2%) screws were totally inserted inside one half of vertebrae and did not pass the middle line. On lateral view, 883 pedicle screws (88%) were inserted at medial position of vertebrae. No neurological deficit was recorded. Average time spent for each screw is 4 minutes.

Conclusion

The Robotic Guidance enhances performance in spinal surgery by increasing the accuracy for pedicle screws placement and reducing neurologic risks. In addition, 33 cases used a percutaneous approach reported herein remark great contributions of Robotic Guidance in procedures without anatomic landmarks.
The Apifix Automatic Self-Correction Technique for Adolescent Idiopathic Scoliosis at 1 ½ Years Follow-Up: A Preliminary Report
Authors: Sekouris Nick , Pilihou Anastasia , Sovatzoglou Apostolos , Soultanis Konstantinos , Karavidas Nick , Flouda Lito , Vlahos Eugenios
Published: April 2016

Introduction

To present a new system for the treatment of adolescent idiopathic scoliosis and the first outcomes. Material-Methods: The new system (Apifix) is an automatic self-correction system, which is fixed by two transpendicular screws on the convex side of the apex of the curve. This system has been used in 4 adolescents with progressive scoliosis of 32°-42°. No blood transfusion was needed. The surgical time was ~1 hour, and the hospital stay was one day. After three weeks, a special program of physiotherapy was started to expand further the system. The Cobb angle, the parameters of sagittal balance and the vertebra rotation (using Nash-Moe technique), has been evaluated during a follow-up of 1 ½ years.

Results

The Cobb angle average improved from 37° to 18,2°. Immediately postoperatively a scoliosis improvement of 13,7° (range: 17°-12°) was noted, and after the physiotherapy other 5° (range: 1°-8°) of improvement was achieved. The sagittal balance parameters remained unchanged. A spontaneous vertebra derotation average from 39,1% to 28,6% was noted using Nash-Moe evaluation.

Conclusions

The first outcomes of the use of this system are encouraging but further research in more patients, and in longer follow-up is needed. This system offers an option between conservative treatment and spinal posterior fusion to be used as an internal brace.
The Impact of Obesity on the Orthopedic Spinal Surgical Operative Time and Hospital Stay at King Khalid University Hospital
Authors: Awwad Waleed , Binown Khalid , Alkadhaib Abdulrahman , Modahi Nawaf
Published: April 2016

Introduction

There is a conflict in the literature regarding the impact of obesity on the duration of surgical operation and the length of hospital stay. Some studies revealed that obesity has no impact on the duration of surgical operation and the length of hospital stay1 and other studies showed the opposite.2 Due to this conflict, we conducted this study to determine whether the obesity has a major role on operation time and hospital stay. Material and Method: The study design is quantitative, observational, and retrospective cohort study on 129 patients who underwent orthopedic spinal surgical operations in King Khalid University Hospital during the years 2013 to 2015. After the exclusion, we reviewed the charts of 106 patients to obtain the duration of the surgical operation, length of hospital stay, the amount of blood loss and the development of postoperative complications. Also, we reviewed the patients’ X-ray and MRI images to measure the space from lamina to skin silhouette and the space from spinous process to skin silhouette.

Results

52.4% of the patients who were included in our study were obese. The results revealed that obese patients had a larger space from the lamina to skin silhouette and a larger space from spinous process to skin silhouette on both X-ray and MRI images. There was no statistically significant difference between obese and non-obese patients regarding time of surgery, blood loss and length of hospital stay. There is no statistically significant difference between obese and non-obese patients regarding the development of postoperative complications, in particular DVT, surgical site infection, surgical revision.

Conclusion

The BMI of the patients who underwent spinal orthopedic surgical operations in King Khalid University Hospital from 2013 to 2015 did not impact the time of surgery, blood loss and length of hospital stay. References Turki AS, Dakhil YA, Turki AA, Ferwana MS. Total knee arthroplasty: effect of obesity and other patients' characteristics on operative duration and outcome. Available at: http://www.wjgnet.com/2218-5836/full/v6/i2/284.htm . Accessed June 6, 2015 McClendon J Jr, Smith TR, Thompson SE, et al. The impact of body mass index on hospital stay and complications after spinal fusion. Neurosurgery 2014;74(1):42–50
Iliac-Cava Complication after L4–L5 Discectomy
Authors: la Villa Juan Fernández , Fernández David Fernández , Asensio Marco Antonio Nogales , Curiel Angel Vega , Pineda Jesús María Herrero
Published: April 2016

Introduction

Lumbar discectomy is one of the most often performed surgical technique at spinal level. The appearance of post discectomy complications is uncommon, being even rarer the vascular ones.

Materials and Methods

In this paper we present the case of a woman who underwent L4-L5 discectomy, left L5 foraminotomy and interspinous UniWallis implant at this level through posterior longitudinal approach. Four weeks after surgery, the patient presented symptoms of right heart failure and systolic-diastolic murmur on aortic area with abdominal and lumbar clear dominance. The CT scan revealed the presence of a right iliac-cava fistula that was treated by endovascular surgery with success.

Results

Postdiscectomy vascular complications are very uncommon (from 0.04 to 0.14%). However, they are potentially fatal for patients. For this reason they should be suspected, identified and treated as soon as possible. In this case, the potential cause could had been a damage at baseline wall of the right iliac artery. This could produce a pseudoaneurysm that progressed overtime and eroded the wall of the vein cava adjacent leading to a right iliac-cava fistula formation due to the blood flow pressure. This justifies the start of the characteristic symptoms. However, one of the peculiarities and particularities of this case is that the clinic started 4 weeks after surgery, not having found in the literature publications with these characteristics until this moment. Even though, it has been described the formation of an aneurysm at 5 -6 weeks after trauma in Vascular Surgery. Moreover, postdiscectomy vascular complications have been reported more frequently in the L4-L5 space, being more frequent lesion in the right iliac artery. In this case, the disc level and laterality agree with the most frequent complication, although approaching has been done by left side. On the other hand, the anterior approaching has the highest rates of vascular complication in spine surgery, but in our case the approaching has been done by left posterior incision.

Conclusions

Postdiscectomy lumbar vascular complications represent a vital risk to the patient. For this reason they must be taken into account for prompt diagnosis and treatment. These complications can be asymptomatic during hospitalization and postoperative and be revealed several weeks later. Posterior approaches in lumbar spine surgery are not exempt from vascular complications, since they frequently occur by anterior approach. This case highlights the importance of taking into account these vascular complications despite the posterior approach as well as after initial satisfactory postoperative course.
The Value of CT and MRI in the Evaluation and Management of Patients with Thoracolumbar Spinal Injuries
Authors: Rajasekaran S. , Vaccaro Alexander R. , Mugesh Rishi , Schroeder Gregory D. , Oner F. C. , Vialle Luiz R. , Chapman Jens R. , Dvorak Marcel F. , Fehlings Michael , Shetty Ajoy Prasad , Schnake Klaus J. , Maheswaran Anupama , Kandziora Frank
Published: April 2016

Introduction

Although imaging has a major role in evaluation and management of thoracolumbar spinal trauma, the exact role of CT and MRI in addition to radiographs for fracture classification and management is unclear. We conducted an online survey base study to evaluate the added value of computed tomography (CT) and magnetic resonance imaging (MRI) in classification, evaluation of stability and management of thoracolumbar injuries.

Methods

Spine surgeons ( n = 41) from around the world classified 30 thoracolumbar fractures. The cases were presented in a three step approach: first plain radiographs, followed by CT and MRI images. Surgeons were asked to classify according to the AO Spine Classification System, evaluate fracture stability and choose management.

Results

Surgeons correctly classified 43.4% of fractures with plain radiographs alone; after additionally evaluating CT and MRI images, this percentage increased by further 18.2% and 2.2% respectively. Instability was diagnosed in 68.5% cases with plain radiographs and this percentage increased to 79.3% after CT ( p < .0001) but did not increase significantly after MRI. AO Type A fractures were identified in 51.7% of fractures with radiographs while the number of type B fractures increased after CT and MRI. The number of type C fractures diagnosed was constant across the three steps. Agreement between radiographs and CT was fair for A-type (k=0.31), poor for B-type (k=0.19), but it was excellent between CT and MRI (k > 0.87). CT and MRI had similar sensitivity in identifying fracture sub types except that MRI had a higher sensitivity (56.5%) for B2 fractures ( p < 0.001).

Conclusion

For accurate classification, radiographs alone were insufficient except for C type injuries. CT is mandatory for accurately classifying thoracolumbar fractures. Though MRI did confer a modest gain in sensitivity in B2 injuries, the study does not support the need for routine MRI in patients without spinal cord injury for classification, assessing instability or need for surgery.
Craniovertebral Junction Meningiomas: Analysis of Clinical and Radiological Results
Authors: Raco Antonino , Pesce Alessandro , Toccaceli Giada , Frati Alessandro , Dugoni Demo Eugenio , Delfini Roberto
Published: April 2016

Introduction

Craniovertebral junction (CVJ) meningiomas are lesions of complex surgical management for the delicate anatomical structures involved and for their tendency to encase/dislocate vital structures such as the vertebrobasilar system and the lower cranial nerves. Matherials and Methods: We analized sex, age, clinical presentation, topography, surgical approach, Simpson Grade Resection, Lower Cranial Nerves postoperative deficit and radiological, histology and clinical follow up at 1, 12 and 24 months of 61 patients affected by CVJ meningiomas, operated on in the Neurosurgical Divisions of the University of Rome “Sapienza” from 1997 to 2013.

Results

78.7% of patients were women (mean age 52.85 years); the onset symptom was pain in 65.5% of cases. The mean preoperative Nurick grade of the sample was 3,78; The most frequent histological type was endotheliomatous (42.8%). Twenty-two patients (5 with lateral and 17 posterolateral axial topography) were treated with posterior median approach; in 39 cases (30 anterolateral and 9 anterior) we performed a posterolateral approach. A Gross Total Removal was achieved in 85.2% of cases. We reported an average neurological improvement in this series (average preoperative Nurick 3.81 and at 12 months 2.13). In 29 patients there was a transient deficit of IX, X and XI cranial nerves. No statistically significant association between surgical approach and temporary or permanent postoperative complications has been found.

Conclusions

In conclusion posterior and posterolateral with/without condilectomy and transposition of VA approaches represents the gold standard for the surgical removal of these tumors and are safe and effective in terms of postoperative morbidity.
Outcome of Kyphoplasty in Vertebral Compression Fractures for Multiple Myeloma
Authors: Debnath Ujjwal K. , Goel Vivek
Published: April 2016

Introduction

The principle symptoms in multiple myeloma result from bone destruction, especially the spine. Kyphoplasty is a new technique that involves the introduction of inflatable bone tamps (IBT) into the vertebral body. The purpose of the IBT is to restore the vertebral body back toward its original height, while creating a cavity that can be filled with highly viscous bone cement. The aim was to evaluate clinical and radiological outcome of kyphoplasty in the treatment of osteolytic vertebral compression fractures resulting from multiple myeloma.

Material and Methods

10 (Ten) patients underwent consecutive kyphoplasty procedures in 13 vertebrae for osteolytic vertebral compression fractures resulting from multiple myeloma. Cement leakage and any complications were recorded. Early objective analysis was made by comparing preoperative and latest VAS and ODI scores. Height restoration was estimated by measuring vertebral height on lateral radiographs.

Results

The mean age of patients was 62years, mean duration of symptoms was 8 months, and mean follow-up was 7.4 (range 6–12) months. There were no major complications related directly to use of this technique. On average, 40% of height lost at the time of fracture was restored. Asymptomatic cement leakage occurred at one level in one patient. Significant improvement in VAS and ODI scores were observed.

Conclusion

Kyphoplasty was efficacious in the treatment of osteolytic vertebral compression fractures resulting from multiple myeloma. Kyphoplasty is associated with early clinical improvement of pain and function as well as some restoration of vertebral body height.
Drops with non-circular footprints
Authors: Ravazzoli Pablo D. , González Alejandro G. , Diez Javier A.
Published: April 2016

In this paper we study the morphology of drops formed on partially wetting substrates, whose footprint is not circular. These drops are consequence of the breakup processes occurring in thin films when anisotropic contact line motions take place. The anisotropy is basically due to the hysteresis of the contact angle since there is a wetting process in some parts of the contact line, while a dewetting occurs in other parts. Here, we obtain a characteristic drop shape from the rupture of a long liquid filament sitting on a solid substrate. We analyze its shape and contact angles by means of goniometric and refractive techniques. We also find a non-trivial steady state solution for the drop shape within the long wave approximation (lubrication theory), and we compare most of its features with experimental data. This solution is presented both in Cartesian and polar coordinates, whose constants must be determined by a certain group of measured parameters. Besides, we obtain the dynamics of the drop generation from numerical simulations of the full Navier–Stokes equation, where we emulate the hysteretic effects with an appropriate spatial distribution of the static contact angle over the substrate.
On the well-posedness of relativistic viscous fluids with non-zero vorticity
Authors: Czubak Magdalena , Disconzi Marcelo M.
Published: April 2016

We study the problem of coupling Einstein’s equations to a physically well-motivated relativistic modification of the Navier-Stokes equations. Under a technical condition for the vorticity, we prove existence and uniqueness in a suitable Gevrey class if the fluid’s dynamic velocity has vanishing divergence, and show that the solutions enjoy the finite propagation speed property.
Banded structures in electron pitch angle diffusion coefficients from resonant wave-particle interactions
Authors: Tripathi A. K. , Singhal R. P. , Khazanov G. V. , Avanov L. A.
Published: April 2016

Electron pitch angle (Dαα) and momentum (Dpp) diffusion coefficients have been calculated due to resonant interactions with electrostatic electron cyclotron harmonic (ECH) and whistler mode chorus waves. Calculations have been performed at two spatial locations L = 4.6 and 6.8 for electron energies ≤10 keV. Landau (n = 0) resonance and cyclotron harmonic resonances n = ±1, ±2, … ±5 have been included in the calculations. It is found that diffusion coefficient versus pitch angle (α) profiles show large dips and oscillations or banded structures. The structures are more pronounced for ECH and lower band chorus (LBC) and particularly at location 4.6. Calculations of diffusion coefficients have also been performed for individual resonances. It is noticed that the main contribution of ECH waves in pitch angle diffusion coefficient is due to resonances n = +1 and n = +2. A major contribution to momentum diffusion coefficients appears from n = +2. However, the banded structures in Dαα and Dpp coefficients appear only in the profile of diffusion coefficients for n = +2. The contribution of other resonances to diffusion coefficients is found to be, in general, quite small or even negligible. For LBC and upper band chorus waves, the banded structures appear only in Landau resonance. The Dpp diffusion coefficient for ECH waves is one to two orders smaller than Dαα coefficients. For chorus waves, Dpp coefficients are about an order of magnitude smaller than Dαα coefficients for the case n ≠ 0. In case of Landau resonance, the values of Dpp coefficient are generally larger than the values of Dαα coefficients particularly at lower energies. As an aid to the interpretation of results, we have also determined the resonant frequencies. For ECH waves, resonant frequencies have been estimated for wave normal angle 89° and harmonic resonances n = +1, +2, and +3, whereas for whistler mode waves, the frequencies have been calculated for angle 10° and Landau resonance. Further, in ECH waves, the banded structures appear for electron energies ≥1 keV, and for whistler mode chorus waves, structures appear for energies >2 keV at L = 4.6 and above 200 eV for L = 6.8. The results obtained in the present work will be helpful in the study of diffusion curves and will have important consequences for diffuse aurora and pancake distributions.
Concentration dependent refractive index of CO2/CH4 mixture in gaseous and supercritical phase
Authors: Giraudet C. , Marlin L. , Bégué D. , Croccolo F. , Bataller H.
Published: April 2016

Carbon dioxide (CO2)/methane (CH4) binary mixtures are investigated at pressure values up to 20 MPa at 303 K in order to investigate the pressure dependence of the optical concentration contrast factor, ∂n/∂cP,T, through gaseous and supercritical phase. Refractive index is measured by means of a Michelson interferometer. Refractivities of the mixtures are found in good agreement with Lorentz-Lorenz predictions after density calculations by means of the AGA8-DC92 equation of state. Experimental polarizabilities of pure fluids are compared to quantum calculations of monomers and dimers for each pressure; it results that the quantity of dimers is small in the investigated thermodynamic conditions. Finally, by extending our experimental database with numerical simulations, we evidence that ∂n/∂cP,T presents a critical enhancement similar to heat capacity.
A computational model for doctoring fluid films in gravure printing
Authors: Hariprasad Daniel S. , Grau Gerd , Schunk P. Randall , Tjiptowidjojo Kristianto
Published: April 2016

The wiping, or doctoring, process in gravure printing presents a fundamental barrier to resolving the micron-sized features desired in printed electronics applications. This barrier starts with the residual fluid film left behind after wiping, and its importance grows as feature sizes are reduced, especially as the feature size approaches the thickness of the residual fluid film. In this work, various mechanical complexities are considered in a computational model developed to predict the residual fluid film thickness. Lubrication models alone are inadequate, and deformation of the doctor blade body together with elastohydrodynamic lubrication must be considered to make the model predictive of experimental trends. Moreover, model results demonstrate that the particular form of the wetted region of the blade has a significant impact on the model's ability to reproduce experimental measurements.
Extended x-ray absorption fine structure spectroscopy and x-ray absorption near edge spectroscopy study of aliovalent doped ceria to correlate local structural changes with oxygen vacancies clustering
Authors: Shirbhate S. C. , Yadav A. K. , Acharya S. A.
Published: April 2016

This study provides atomic scale insight to understand the role of aliovalent dopants on oxygen vacancies clustering and dissociation mechanism in ceria system in order to enhance the performance of oxy-ion conductor. Dopants induced microscale changes in ceria are probed by extended X-ray absorption fine structure spectroscopy, X-ray absorption near edge spectra, and Raman spectroscopy. The results are explored to establish a correlation between atomic level structural changes (coordination number, interatomic spacing) → formation of dimer and trimer type cation-oxygen vacancies defect complex (intrinsic and extrinsic) → dissociation of oxygen vacancies from defect cluster → ionic conductivity temperature. It is a strategic approach to understand key physics of ionic conductivity mechanism in order to reduce operating temperature of electrolytes for intermediate temperature (300–450 °C) electrochemical devices for the first time.
Phase formation and texture of thin nickel germanides on Ge(001) and Ge(111)
Authors: De Schutter B. , Van Stiphout K. , Santos N. M. , Bladt E. , Jordan-Sweet J. , Bals S. , Lavoie C. , Comrie C. M. , Vantomme A. , Detavernier C.
Published: April 2016

We studied the solid-phase reaction between a thin Ni film and a single crystal Ge(001) or Ge(111) substrate during a ramp anneal. The phase formation sequence was determined using in situ X-ray diffraction and in situ Rutherford backscattering spectrometry (RBS), while the nature and the texture of the phases were studied using X-ray pole figures and transmission electron microscopy. The phase sequence is characterized by the formation of a single transient phase before NiGe forms as the final and stable phase. X-ray pole figures were used to unambiguously identify the transient phase as the ϵ-phase, a non-stoichiometric Ni-rich germanide with a hexagonal crystal structure that can exist for Ge concentrations between 34% and 48% and which forms with a different epitaxial texture on both substrate orientations. The complementary information gained from both RBS and X-ray pole figure measurements revealed a simultaneous growth of both the ϵ-phase and NiGe over a small temperature window on both substrate orientations.
Self-decorated Au nanoparticles on antireflective Si pyramids with improved hydrophobicity
Authors: Saini C. P. , Barman A. , Kumar M. , Satpati B. , Som T. , Kanjilal A.
Published: April 2016

Post-deposition annealing mediated evolution of self-decorated Au nanoparticles (NPs) on chemically etched Si pyramids is presented. A distinct transformation of Si surfaces from hydrophilic to hydrophobic is initially found after chemical texturing, showing an increase in contact angle (CA) from 58° to 98° (±1°). Further improvement of hydrophobicity with CA up to ∼118° has been established after annealing a 10 nm thick Au-coated Si pyramids at 400 °C that led to the formation of Au NPs on Si facets along with self-ordering at the pyramid edges. Detailed x-ray diffraction studies suggest the evolution of crystalline Au NPs on strained Si facets. Microstructural studies, however, indicate no mixing of Au and Si atoms at the Au/Si interfaces, instead of forming Au nanocrystals at 400 °C. The improved hydrophobicity of Si pyramids, even with Au NPs can be explained in the light of a decrease in solid fractional surface area according to Wenzel's model. Moreover, a sharp drop in specular reflectance from Si pyramids in the range of 300–800 nm, especially in the ultraviolet region up to ∼0.4% is recorded in the presence of Au NPs by ultraviolet-visible spectroscopy, reflecting the possible use in photovoltaic devices with improved antireflection property.
Nanowire LEDs grown directly on flexible metal foil
Authors: May Brelon J. , Sarwar A. T. M. Golam , Myers Roberto C.
Published: April 2016

Using molecular beam epitaxy, self-assembled AlGaN nanowires are grown directly on Ta and Ti foils. Scanning electron microscopy shows that the nanowires are locally textured with the underlying metallic grains. Photoluminescence spectra of GaN nanowires grown on metal foils are comparable to GaN nanowires grown on single crystal Si wafers. Similarly, photoluminescence lifetimes do not vary significantly between these samples. Operational AlGaN light emitting diodes are grown directly on flexible Ta foil with an electroluminescence peak emission of ∼350 nm and a turn-on voltage of ∼5 V. These results pave the way for roll-to-roll manufacturing of solid state optoelectronics.
Extrinsic response enhancement at the polymorphic phase boundary in piezoelectric materials
Authors: Ochoa Diego A. , Esteves Giovanni , Jones Jacob L. , Rubio-Marcos Fernando , Fernández José F. , García José E.
Published: April 2016

Polymorphic phase boundaries (PPBs) in piezoelectric materials have attracted significant interest in recent years, in particular, because of the unique properties that can be found in their vicinity. However, to fully harness their potential as micro-nanoscale functional entities, it is essential to achieve reliable and precise control of their piezoelectric response, which is due to two contributions known as intrinsic and extrinsic. In this work, we have used a (K,Na)NbO3-based lead-free piezoceramic as a model system to investigate the evolution of the extrinsic contribution around a PPB. X-ray diffraction measurements are performed over a wide range of temperatures in order to determine the structures and transitions. The relevance of the extrinsic contribution at the PPB region is evaluated by means of nonlinear dielectric response measurements. Though it is widely appreciated that certain intrinsic properties of ferroelectric materials increase as PPBs are approached, our results demonstrate that the extrinsic contribution also maximizes. An enhancement of the extrinsic contribution is therefore also responsible for improving the functional properties at the PPB region. Rayleigh's law is used to quantitatively analyze the nonlinear response. As a result, an evolution of the domain wall motion dynamics through the PPB region is detected. This work demonstrates that the extrinsic contribution at a PPB may have a dynamic role in lead-free piezoelectric materials, thereby exerting a far greater influence on their functional properties than that considered to date.
A method to measure the thermovoltage with a high spatial resolution
Authors: Sotthewes K. , Siekman M. H. , Zandvliet H. J. W.
Published: April 2016

We have recorded spatial maps of the thermovoltage of a Au(111) surface with a scanning tunneling microscope. The method relies on an approach where we record quasi-simultaneously the normal topography as well as the thermovoltage by switching the feedback and sample bias on and off. This setup can be combined with standard scanning tunneling microscopy and scanning tunneling spectroscopy techniques. The thermovoltage, which arises from a temperature difference between scanning tunneling microscope tip and sample, is very sensitive to small variations of the local electronic density of states in vicinity of the Fermi level. Near step edges we have observed well-defined Friedel oscillations, while for the herringbone reconstruction, small variations of the local work-function are measured. By altering the tip-sample distance, the thermovoltage contrast can be adjusted.
In-situ SiNx/InN structures for InN field-effect transistors
Authors: Zervos Ch. , Adikimenakis A. , Beleniotis P. , Kostopoulos A. , Kayambaki M. , Tsagaraki K. , Konstantinidis G. , Georgakilas A.
Published: April 2016

Critical aspects of InN channel field-effect transistors (FETs) have been investigated. SiNx dielectric layers were deposited in-situ, in the molecular beam epitaxy system, on the surface of 2 nm InN layers grown on GaN (0001) buffer layers. Metal-insulator-semiconductor Ni/SiNx/InN capacitors were analyzed by capacitance-voltage (C-V) and current-voltage measurements and were used as gates in InN FET transistors (MISFETs). Comparison of the experimental C-V results with self-consistent Schrödinger-Poisson calculations indicates the presence of a positive charge at the SiNx/InN interface of Qif ≈ 4.4 – 4.8 × 1013 cm−2, assuming complete InN strain relaxation. Operation of InN MISFETs was demonstrated, but their performance was limited by a catastrophic breakdown at drain-source voltages above 2.5–3.0 V, the low electron mobility, and high series resistances of the structures.
Origin of the plasma scalds in dielectric coatings induced by 1ω laser
Authors: Wang Hu , Qi Hongji , Zhao Jiaoling , Wang Bin , Chai Yingjie , Yu Zhen , Shao Jianda
Published: April 2016

The plasma scalds initiated by a 1053 nm (1ω) nanosecond laser are separated from the defect-induced damage pits, which is verified as a result of the ionization wavefront with the subnanosecond laser. Considering the beam reflection from solid-state absorption fronts during the damage process, a theoretical scalding threshold about 6.84 J/cm2 (12 ns) based on the energy required to start an air avalanche is evaluated and agrees well with the experimental scalding threshold. The occurrence order of the initial explosion and subsequent ionization wavefront is verified to explain most of the damage morphologies caused by the 1ω laser. In addition to the significance in laser conditioning or cleaning for a high-power laser system, the results also indicate that through the occurrence of plasma scalds it is possible to mark the onset time of air plasma during laser-coating interaction.
Origin and enhancement of spin polarized current in diluted magnetic oxides by oxygen vacancies
Authors: Chou Hsiung , Yang Kung-Shang , Tsao Yao-Chung , Dwivedi G. D. , Lin Cheng-Pang , Sun Shih-Jye , Lin L. K. , Lee S. F.
Published: April 2016

Spin polarized current (SPC) is a crucial characteristic of diluted magnetic oxides due to the potential application of oxides in spintronic devices. However, most research has been focused on ferromagnetic properties rather than polarization of electric current, because direct measurements are difficult and the origin of SPC has yet to be fully understood. The method to increase the SPC percentage is beyond practical consideration at present. To address this problem, we focus on the role of oxygen vacancies (VO) on SPC, which are controlled by growing the Co-doped ZnO thin-films at room temperature in a reducing atmosphere [Ar + (1%–30%)H2]. We found that the conductivity increases with an increase of VO via two independent channels: the variable range hopping (VRH) within localized states and the itinerant transport in the conduction band. The point contact Andreev reflection measurements at 4.2 K, where the electric conduction is governed only by the VRH mechanism, prove that the current flowing in the VRH hopping channel is SPC. The percentage of SPC increases with the introduction of VO and increase in its concentration. The transport measurement shows that by manipulating VO, one can control the percentage of VRH hopping conduction such that it can even dominate room temperature conduction. The highest achieved SPC ratio at room temperature was 80%.
A method for age estimation in the swamp wallaby (Wallabia bicolor)
Authors: Death Clare , Coulson Graeme
Published: April 2016

We investigated molar progression as an index of age in the swamp wallaby (Wallabia bicolor) by examining a small sample of known-age specimens. We demonstrate a strong relationship between age and molar index in W. bicolor [log10(age, in days) = (MI + 4.6864)/2.2179, R2 = 0.93], which will facilitate more detailed investigation of this species.
A Fortuitous, Mild Catalytic Carbon–Carbon Bond Hydrogenolysis by a Phosphine-Free Catalyst
Authors: Rasu Loorthuraja , Rennie Ben , Miskolzie Mark , Bergens Steven H.
Published: April 2016

The putative catalyst trans-[Ru((S,S)-skewphos)(H)2((R,R)-dpen)] (skewphos = 2,4-bis(diphenylphosphino)pentane; dpen = 1,2-diphenylethylenediamine) transforms the trifluoroacetyl amide 2,2,2-trifluoro-1-(piperidin-1-yl)ethanone under mild conditions (4 atm H2, room temperature, 4–24 h, 1 mol-% Ru, 15 mol-% KOtBu in tetrahydrofuran) to generate the formylated amine 1-formylpiperidine and fluoroform via C–C bond hydrogenolysis. Catalysts are also prepared by reacting cis-[Ru(η3-C3H5)(MeCN)2(COD)]BF4 (COD = 1,5-cyclooctadiene) with diamine ligands in situ. Low-temperature NMR studies provided insight into this reaction.
The influence of population mobility on changing patterns of HIV acquisition: lessons for and from Australia
Authors: Crawford G. , Lobo R. , Brown G. , Maycock B.
Published: April 2016

Investment, bipartisan support and involvement from affected communities have characterised Australia's HIV response, and helped maintain a low prevalence epidemic. Patterns of HIV acquisition are changing, with an increasing number of infections acquired overseas by migrant and mobile populations. A coordinated national response is required to address HIV acquisition in the context of population mobility.
Extended synaptotagmins are Ca
2+
-dependent lipid transfer proteins at membrane contact sites
Authors: Yu Haijia , Liu Yinghui , Gulbranson Daniel R. , Paine Alex , Rathore Shailendra S. , Shen Jingshi
Published: April 2016

Significance

Lipid transfer proteins (LTPs) operating at membrane contact sites play fundamental roles in lipid homeostasis, organelle dynamics, and cell–environment interactions. Imbalances in LTPs are associated with a range of human diseases. For example, aberrant extended synaptotagmin (E-Syt) activities are implicated in neurological disorders. Our findings establish E-Syts as a novel class of LTPs with activities that are controlled by Ca
2+
. We also show that lipid transport, like vesicle trafficking, can be subject to tight Ca
2+
regulation, thus expanding the role of Ca
2+
in intracellular membrane transport. These findings broaden our knowledge of lipid transport in the cell and set the stage for understanding the pathogenesis of LTP-associated diseases.
Cellular uptake and anticancer activity of carboxylated gallium corroles
Authors: Pribisko Melanie , Palmer Joshua , Grubbs Robert H. , Gray Harry B. , Termini John , Lim Punnajit
Published: April 2016

Significance

Corroles are macrocyclic molecules related to porphyrins that exhibit intense light absorptions in the visible region. They also are very bright emitters, with luminescence quantum yields over 50% in some cases. Importantly, we have discovered that two corroles functionalized with carboxylate groups at different ring locations exhibit anticancer activity superior to cisplatin. Although the synthetic route to direct carboxylation of the tetrapyrrolic framework requires the use of phosgene, installing aminocaproate on the fluorophenyl ring by nucleophilic aromatic substitution uses mild conditions with biocompatible reagents, requiring only simple purification and providing ready access to structurally complex corroles. Carboxylated corroles are very rapidly taken up by cells, with an order of magnitude gain in dark cytotoxicity likely owing to greater cell permeability.
Dual inhibition of Ang-2 and VEGF receptors normalizes tumor vasculature and prolongs survival in glioblastoma by altering macrophages
Authors: Peterson Teresa E. , Kirkpatrick Nathaniel D. , Huang Yuhui , Farrar Christian T. , Marijt Koen A. , Kloepper Jonas , Datta Meenal , Amoozgar Zohreh , Seano Giorgio , Jung Keehoon , Kamoun Walid S. , Vardam Trupti , Snuderl Matija , Goveia Jermaine , Chatterjee Sampurna , Batista Ana , Muzikansky Alona , Leow Ching Ching , Xu Lei , Batchelor Tracy T. , Duda Dan G. , Fukumura Dai , Jain Rakesh K.
Published: April 2016

Significance

Inhibition of the VEGF/VEGF receptor (VEGFR) pathway has failed to increase overall survival in phase III trials in patients with glioblastoma (GBM). Previously we identified the angiopoietin-2 (Ang-2)/TEK receptor tyrosine kinase (Tie-2) pathway as a potential driver of resistance to VEGF inhibition in GBM. Here we show that dual inhibition of VEGFRs and Ang-2 inhibits tumor growth and prolongs vessel normalization compared with VEGFR inhibition alone, resulting in improved survival in murine GBM models. Furthermore, by blocking macrophage recruitment, we demonstrate that macrophages contribute to the beneficial effects of dual therapy.
The quantum needle of the avian magnetic compass
Authors: Hiscock Hamish G. , Worster Susannah , Kattnig Daniel R. , Steers Charlotte , Jin Ye , Manolopoulos David E. , Mouritsen Henrik , Hore P. J.
Published: April 2016

Significance

Billions of birds fly thousands of kilometers every year between their breeding and wintering grounds, helped by an extraordinary ability to detect the direction of the Earth’s magnetic field. The biophysical sensory mechanism at the heart of this compass is thought to rely on magnetically sensitive, light-dependent chemical reactions in cryptochrome proteins in the eye. Thus far, no theoretical model has been able to account for the <5° precision with which migratory birds are able to detect the geomagnetic field vector. Here, using computer simulations, we show that genuinely quantum mechanical, long-lived spin coherences in realistic models of cryptochrome can provide the necessary precision. The crucial structural and dynamical molecular properties are identified.
Monoclonal antibody therapy for Junin virus infection
Authors: Zeitlin Larry , Geisbert Joan B. , Deer Daniel J. , Fenton Karla A. , Bohorov Ognian , Bohorova Natasha , Goodman Charles , Kim Do , Hiatt Andrew , Pauly Michael H. , Velasco Jesus , Whaley Kevin J. , Altmann Friedrich , Gruber Clemens , Steinkellner Herta , Honko Anna N. , Kuehne Ana I. , Aman M. Javad , Sahandi Sara , Enterlein Sven , Zhan Xiaoguo , Enria Delia , Geisbert Thomas W.
Published: April 2016

Significance

There are no Food and Drug Administration approved drugs available for preventing or treating Argentine hemorrhagic fever (AHF), and the current treatment option is limited to administration of immune plasma. With the expanding clinical use of monoclonal antibodies (mAbs) for acute and chronic conditions, it has become clear that mAbs offer a highly specific, potent, and generally safe drug platform for antivirals, and may be a useful alternative to immune plasma. Here, we show that mAbs are effective in the Junin virus guinea pig model and likely to be an economical therapy for AHF.
Processing text and pictures in procedural instructions
Authors: Ganier Franck
Published: April 2016

Background. Following procedural instructions normally requires the learner to interpret written information before carrying out any action.This interpretation entails transforming pictorial and/or linguistic information into a series of actions. Current psychological models propose that these two kinds of information are not processed in the same way,and that pictures lead more directly to the construction of a mental representation than does text. If this is so, then giving pictorial instructions to carry out an action seems more appropriate than giving text.However, processing instructions sometimes fails, even with picture formats. One approach to studying why this kind of communication fails is to investigate how textual and pictorial information is processed.
Approaches and developments in studying the human microbiome network
Authors: Nitzan Mor , Mintzer Sefi , Margalit Hanah
Published: April 2016

The human microbiome is dynamic and unique to each individual, and its role is being increasingly recognized in healthy physiology and in disease, including gastrointestinal and neuropsychiatric disorders. Therefore, characterizing the human microbiome and the factors that shape its bacterial population, how they are related to host-specific attributes, and understanding the ways in which it can be manipulated and the phenotypic consequences of such manipulations are of great importance. Characterization of the microbiome so far has been mostly based on compositional studies alone, where relative abundances of different species are compared in different conditions, such as health and disease. However, inter-relationships among the bacterial species, such as competition and cooperation over metabolic resources, may be an important factor that affects the structure and function of the microbiome. Here we review the network-based approaches in answering such questions and explore the first attempts that focus on the interactions facet, complementing compositional studies, towards understanding the microbiome structure and its complex relationship with the human host.
Prohibition rules for three-node substructures in ordered food webs with cannibalistic species
Authors: Guill Christian , Paulau Pavel
Published: April 2016

We evaluate the spectrum of ordered three-node substructures in food webs taking self-links (cannibalism) into account. If the order of nodes in the network cannot be neglected, 512 substructures can be distinguished. Simple statistical models of networks impose constraints on the structure that prohibit a large number of substructures completely. We analyse two variants of the widely used niche model, the original niche model and the generalised niche model, and show analytically and numerically that they exclude 344 and 320 substructures, respectively. The prohibition rules for three-node substructures in the two niche-model variants are further contrasted with a large set of empirical food webs, which reveals that up to about 30% of the three-node substructures that occur in empirical food webs are prohibited by the model algorithms.
Attention and attribute overlap in preferential choice
Authors: Bhatia Sudeep
Published: April 2016

Attributes that are common, or overlapping, across alternatives in two-alternative forced preferential choice tasks are often non-diagnostic. In many settings, attending to and evaluating these attributes does not help the decision maker determine which of the available alternatives is the most desirable. For this reason, many existing behavioural theories propose that decision makers ignore common attributes while deliberating. Across six experiments, we find that decision makers do direct their attention selectively and ignore attributes that are not present in or associated with either of the available alternatives. However, they are as likely to attend to common attributes as they are to attend to attributes that are unique to a single alternative. These results suggest the need for novel theories of attention in preferential choice.
Kindlin-2 directly binds actin and regulates integrin outside-in signaling
Authors: Bledzka Kamila , Bialkowska Katarzyna , Sossey-Alaoui Khalid , Vaynberg Julia , Pluskota Elzbieta , Qin Jun , Plow Edward F.
Published: April 2016

Reduced levels of kindlin-2 (K2) in endothelial cells derived from K2+/− mice or C2C12 myoblastoid cells treated with K2 siRNA showed disorganization of their actin cytoskeleton and decreased spreading. These marked changes led us to examine direct binding between K2 and actin. Purified K2 interacts with F-actin in cosedimentation and surface plasmon resonance analyses and induces actin aggregation. We further find that the F0 domain of K2 binds actin. A mutation, LK47/AA, within a predicted actin binding site (ABS) of F0 diminishes its interaction with actin by approximately fivefold. Wild-type K2 and K2 bearing the LK47/AA mutation were equivalent in their ability to coactivate integrin αIIbβ3 in a CHO cell system when coexpressed with talin. However, K2-LK47/AA exhibited a diminished ability to support cell spreading and actin organization compared with wild-type K2. The presence of an ABS in F0 of K2 that influences outside-in signaling across integrins establishes a new foundation for considering how kindlins might regulate cellular responses.
Doa1 targets ubiquitinated substrates for mitochondria-associated degradation
Authors: Wu Xi , Li Lanlan , Jiang Hui
Published: April 2016

Mitochondria-associated degradation (MAD) mediated by the Cdc48 complex and proteasome degrades ubiquitinated mitochondrial outer-membrane proteins. MAD is critical for mitochondrial proteostasis, but it remains poorly characterized. We identified several mitochondrial Cdc48 substrates and developed a genetic screen assay to uncover regulators of the Cdc48-dependent MAD pathway. Surprisingly, we identified Doa1, a substrate-processing factor of Cdc48 that inhibits the degradation of some Cdc48 substrates, as a critical mediator of the turnover of mitochondrial Cdc48 substrates. Deletion of DOA1 causes the accumulation and mislocalization of substrates on mitochondria. Profiling of Cdc48 cofactors shows that Doa1 and Cdc48-Ufd1-Npl4 form a functional complex mediating MAD. Biochemically, Doa1 interacts with ubiquitinated substrates and facilitates substrate recruitment to the Cdc48-Ufd1-Npl4 complex. Functionally, Doa1 is critical for cell survival under mitochondrial oxidative stress, but not ER stress, conditions. Collectively, our results demonstrate the essential role of the Doa1–Cdc48-Ufd1-Npl4 complex in mitochondrial proteostasis and suggest that Doa1 plays dual roles on the Cdc48 complex.