bluuebunny/crossref_metadata_2025 huggingface dataset:
New Classification of Polydactyly of the Foot on the Basis of Syndactylism, Axis Deviation, and Metatarsal Extent of Extra Digit
Authors: Seok Hyo Hyun , Park Ji Ung , Kwon Sung Tack
Published: May 2013

Background Polydactyly of the foot is one of the most frequent anomalies of the limbs. However, most classification systems are based solely on morphology and tend to be inaccurate and less relevant to surgical methods and results. The purpose of this study is to present our new classification of polydactyly of the foot, which can serve as a predictor of treatment and prognosis.

Methods To find a correlation between the various morphologic traits of polydactyly of the foot and the treatment plan and outcomes, we reviewed 532 cases of polydactyly of the foot in 431 patients treated in our hospital, expanding on our previous study that described polydactyly based on the importance of metatarsal bone status and varus deformity. The records of patients were evaluated and compared with previous studies at other centers.

Results Unsatisfactory results were seen in 36 cases, which included 5 cases of incomplete separation due to syndactylism, 23 cases of axis deviation, and 8 cases of remnants of extra-digit metatarsal bones. The locus of the polydactyly, or the digit which was involved, did not seem to affect the final postoperative outcomes in our study. Three factors-syndactylism, axis deviation, and metatarsal extension-are the major factors related to treatment strategy and prognosis. Therefore, we developed a new classification system using three characters (S, A, M) followed by three groups (0, 1, 2), to describe the complexity of polydactyly of the foot, such as S1A2M2.

Conclusions Our new classification could provide a communicable description to help determine the surgical plan and predict outcomes.
Surgical Options for Malignant Skin Tumors of the Hand
Authors: Yun Min Ji , Park Ji Ung , Kwon Sung Tack
Published: May 2013

Background Primary malignant tumors of the hand, although unusual, may present varied and often complex clinical problems. The main treatment modality of skin cancer of the hand has changed.

Methods We retrospectively reviewed the medical records of 43 patients who underwent surgery for malignant skin tumors of the hand during an 18-year period, from September 1994 to February 2012. The characteristics of the tumor, methods of reconstruction, and long-term results were reviewed.

Results We had 43 patients with 27 melanomas, 14 squamous cell carcinomas, and 2 sarcomas. Their ages ranged from 19 to 74 years (mean, 53.4±14.5 years), from 46 to 79 years (mean, 59.7±9.6 years), and from 15 to 43 years (mean, 29±19.8 years), respectively. Thirty-four cases occurred on the fingertip (16 of those cases on the thumb), 5 cases occurred on the palm, and 4 cases on the dorsum of the hand. Amputation was most frequently used in early cases, but recently, tissue-sparing excision has been performed frequently. The incidence of local recurrence was 3 cases and distant metastasis was 1 case, and the 5-year survival rate was 100%, except in 4 cases due to follow-up loss.

Conclusions The principles of treatment-to be curative and to preserve function and appearance-are important points. "Preservative surgery" preserves function and cosmesis of the involved finger or hand dorsum or palm. Preservative surgery not only emphasizes less resection and surgery of a smaller scale, but also optimal reconstruction of the soft tissue defect of the digit.
A Salvage Operation for Total Penis Amputation Due to Circumcision
Authors: Ince Bilsev , Gundeslioglu Ayse Ozlem
Published: May 2013

Circumcision is one of the most common rituals in Jewish and Islamic cultures. It may also be performed for phimosis correction or the treatment of recurrent balanitis. Although circumcision is considered to be a technically easy and safe surgical procedure with no significant risk, it may lead to severe complications such as necrotizing fasciitis or total penis amputation. In this report, we present a case of penis amputation at two levels occurring with third-degree burns due to electrocautery during circumcision. Although penile replantation was attempted, it was unsuccessful due to burn damage to the veins. After restoration of the functional structures, the penis was buried in the inguinal area by reepithelization to maintain blood circulation. The recovery of the penis was successful. This case is presented as a novel example of groin flap surgery to achieve a functionally and aesthetically acceptable outcome in a salvage operation for a penis with significant traumatic injury, which has not been previously reported in the literature.
Subcision Using a Spinal Needle Cannula and a Thread for Prominent Nasolabial Fold Correction
Authors: Lee Sang-Yeul , Sung Kun-Yong
Published: May 2013

Deepening of the nasolabial crease is an esthetically unpleasing aging phenomenon occurring in the midface. Various treatment modalities have been introduced to improve the appearance of prominent nasolabial folds, all of which have pros and cons. Currently, a minimally invasive technique using synthetic dermal fillers is most commonly used. A simple and easy subcision procedure using a wire scalpel has also been used and reported to be effective for prominent nasolabial fold correction, with minimal complications. As an alternative to the wire scalpel, we used a 20-gauge metal type spinal needle cannula (Hakko Co.) and 4-0 Vicryl suture (Ethicon Inc.) for subcision of nasolabial folds. This technique is less expensive than the use of a wire scalpel and easily available when needed. Therefore, on the basis of favorable results, our modified subcision technique may be considered effective for prominent nasolabial fold correction.
Redoable Tie-Over Dressing Using Multiple Loop Silk Threads
Authors: Jo Hyeon Jong , Kim Jun Sik , Kim Nam Gyun , Lee Kyung Suk , Choi Jae Hoon
Published: May 2013

After skin grafting, to prevent hematoma or seroma collection at the graft site, a tie-over dressing has been commonly used. However, although the conventional tie-over dressing by suture is a useful method for securing a graft site, refixation is difficult when repeated tie-over dressing is needed. Therefore, we recommend a redoable tie-over dressing technique with multiple loops threads and connecting silk threads. After the raw surface of each of our cases was covered with a skin graft, multiple loop silk thread attached with nylon at the skin graft margin. We applied the ointment gauze and wet cotton/fluffy gauze over the skin graft, then fixed the dressing by connecting cross-counter multiple loop thread with connecting silk threads. When we opened the tie-over dressing by cutting the connecting silk threads, we repeated the tie-over dressing with the same method. The skin graft was taken successfully without hematoma or seroma collection or any other complications. In conclusion, we report a novel tie-over dressing enabling simple fixation of the dressing to maintain proper tension for wounds that require repetitive fixation. Further, with this reliable method, the skin grafts were well taken.
A Comparative Study to Evaluate a Simple Method for the Management of Postoperative Bleeding Following Palatoplasty
Authors: Rossell-Perry Percy , Schneider William J , Gavino-Gutierrez Arquímedes M.
Published: May 2013

Bleeding, is one of the most common postoperative complications after palatoplasty in patients with cleft palate. The purpose of this article is to present our experience using a Foley catheter balloon for perioperative palatoplasty bleeding management. A retrospective data analysis was performed for all cases of palatoplasty performed by the author from 1999 to 2012 that experienced postoperative hemorrhage. These patients were managed by utilizing posterior nasal compression with a Foley catheter balloon for the period 2006 to 2012. We have compared two methods (we use before 2006 the reoperative method) with regards to the later development of palatal fistulae and cases with reoperative hemostasis. The study found no statistically significant differences between the conventional and proposed method in relation to the development of palatal fistulae (P=0.7). These findings suggest that nasal packing using a Foley balloon is a safe and effective method for postoperative bleeding control after palatoplasty in patients with cleft palate.
Critique de la réflexivité (mais est-ce donc possible ?)
Authors: Couturier Yves
Published: May 2013

La réflexivité constitue une thématique à la mode, qui traduit à sa façon une évolution importante dans la façon de penser les pratiques sociales. Mais pour cette même raison, sa conception est encore instable, et les sens et usages dont elle est l’objet sont pour le moins multiples. Pour effectuer un travail de conception sur la notion de réflexivité, il faut d’abord montrer en quoi elle est objet d’une inflation normative la posant comme catégorie logique si attendue qu’une critique n’en est presque pas pensable. Or, cette aura très (trop) positive doit être dispersée pour qu’un travail théorique rigoureux puisse émerger. Le présent article propose de contribuer à une théorie de la réflexivité en décrivant l’aire de dispersion des usages de cette notion, distribués sur cinq plans logiques.
La pratique réflexive en enseignement supérieur : d’une approche théorique à une perspective de développement professionnel
Authors: Lison Christelle
Published: May 2013

La formation des enseignants du supérieur est de plus en plus valorisée dans les institutions du monde entier. Les modèles de formation et de valorisation semblent par ailleurs multiples. Considérant que le développement professionnel initial ou continu des enseignants passe, du moins en partie, par le développement d’une pratique réflexive appuyée sur la base d’écrits scientifiques, nous proposons d’une part de réfléchir à un modèle de pratique réflexive, celui de Kelchtermans, à travers quatre dimensions (instrumentale, morale, politique et affective), et d’autre part à la formation des enseignants du supérieur dans une perspective de Scholarship of Teaching and Learning1. Ce texte, qui se veut avant tout une réflexion ouverte sur le développement de la pratique réflexive en formation à l’enseignement supérieur, se base sur des écrits scientifiques, mais également, en bonne partie, sur notre pratique d’enseignante.
Considérations méthodologiques pour aborder la compétence à « réfléchir » ou à « faire réfléchir » sur sa pratique en enseignement
Authors: Chaubet Philippe , Correa Molina Enrique , Gervais Colette
Published: May 2013

L’article propose une démarche méthodologique permettant d’identifier la réflexion professionnelle chez des stagiaires en formation à l’enseignement. En effet, la capacité d’analyser sa pratique de façon réflexive est une composante d’une compétence professionnelle à développer selon le ministère de l’Éducation du Québec. Une certaine forme de réflexion chez les étudiants est donc à acquérir et, du point de vue des tuteurs de stage, à faire acquérir. Quels sont les critères implicites que les enseignants associés des écoles ou les superviseurs universitaires identifient afin d’évaluer la présence ainsi que la qualité de la compétence réflexive chez le stagiaire ? L’étude identifie une dizaine de points de repère afin de favoriser chez les tuteurs de stage l’évaluation de la compétence réflexive de leurs stagiaires. L’article valide ces critères à partir d’un extrait de discours de stagiaire, puis confronte cet extrait à une autre approche, consistant à détecter des reconceptualisations chez les stagiaires pour dépister de la réflexion. Une certaine cohérence s’établit avec les critères empiriques d’identification de la réflexion identifiés par induction chez les tuteurs de stage. S’ensuit une discussion sur ces critères en lien avec les approches méthodologiques adoptées. La recherche utilise un devis qualitatif et s’appuie sur des entretiens semi-structurés.
Self-Assessment of Professional Growth Through Reflective Portfolios
Authors: Nickel Jodi
Published: May 2013

This study aims to discern how teacher candidates develop reflective capacity by self-assessing their portfolios. While the goal was to help first-year teacher candidates assess their progress toward achieving provincial teaching competencies, many called attention to the interconnections between their academic artifacts and their personal profiles. This led the researcher to refine the focus of the portfolio to the emergence of professional identity and developing structures to support this type of self-awareness.
Has Reflective Practice Done More Harm than Good in Teacher Education?
Authors: Russell Tom
Published: May 2013

Why do we emphasize reflective practice so extensively in pre-service teacher education? What evidence do we have that frequent references to reflection are improving the quality of the teachers we prepare for certification and careers in teaching? Whatever reflection and reflective practice are, they are not ends in themselves; hopefully, they are means to the end of better teaching practices and better learning by students in schools. In this article I explore reflection and reflective practice from several perspectives, including my personal experiences as a teacher educator working with individuals preparing to become teachers of physics. The question asked in the title captures my fear that the ways teacher educators have responded to and made use of the concepts of reflection and reflective practice may be doing more harm than good in pre-service teacher education. To begin, I consider teacher education practices before and after the arrival of the term reflective practice. I then consider elements of Schön’s (1983) work and review five articles about reflective practice in teacher education; this is not a formal literature review, but rather an effort to show how virtually every article about reflective practice seems to be driven by its author’s personal perspective. The article continues with personal interpretations and illustrations and concludes with five generalizations about teacher education practices that indicate that much more work needs to be done if references to reflection are to do more good than harm in preservice teacher education programs.
What We Owe to Donald Schön: Three Educators in Conversation
Authors: MacKinnon Allan , Clarke Anthony , Erickson Gaalen
Published: May 2013

Readers with even a casual acquaintance with the research literature in the field of teacher education over the past 25 years will be aware of the dramatic increase in the use of the term ‘reflection’ to describe desired attributes [outcomes/behaviours] of participants in professional development programs for both novice and experienced teachers. Our intent is to draw upon our own collective experiences in our research and teaching practices to map out how and why we initially became intrigued with the many meanings associated with the term and how our understandings have changed over the past 25 or so years. We think that this type of ‘reflection-upon-experience’ is best revealed through the use of a narrative style and therefore we deliberately use a conversational format to convey our story.
Changing the Paradigm of Response to Coastal Storms
Authors: Hapke Cheryl J. , Stockdon Hilary F. , Schwab William C. , Foley Mary K.
Published: May 2013

Federal, state, and local agencies mounted a massive preparation and response to post–tropical storm Sandy, which made landfall along the northern New Jersey coast on 29 October 2012. The data collected and knowledge gained in response to Sandy are unprecedented and provide critical information to agencies, local emergency responders, and coastal managers and planners.
Another “Great Tolbachik” Eruption?
Authors: Edwards Ben , Belousov Alexander , Belousova Marina , Volynets Anna , Melnikov Dmitry , Chirkov Sergey , Senyukov Sergey , Gordeev Evgenii , Muraviev Yaroslav , Izbekov Pavel , Demianchuk Yury
Published: May 2013

On 27 November 2012 at 1715 local time, a focused swarm of earthquakes was interpreted as the start of a new ongoing eruption on the south flank (Tolbachinsky Dol) of Plosky Tolbachik volcano in east central Kamchatka, Russia (Figure 1a) [Samoylenko et al., 2012]. Visual observations on 29 November showed ash shooting from two fractures as well as long, rapidly moving lava flows. Although the initial ash clouds reached 6 kilometers in height, subsequent ashfall has been limited to the area around the main vents, and no permanent settlements are in danger from advancing lava flows (the closest settlements are about 40 kilometers from the volcano). Including this eruption, six different volcanoes are presently active in Kamchatka.
Mars Summit Explores Options for Human Missions to the Red Planet
Authors: Showstack Randy
Published: May 2013

The United States “needs to begin the homesteading and settlement of Mars,” Edwin “Buzz” Aldrin told participants at the Humans to Mars Summit on 8 May in Washington, D. C. “It is within reach technically and budgetarily. Even in a period of fiscal challenges, the United States needs to consider this program with long‐term planning.”
Carbon dioxide tops 400 ppm at Mauna Loa, Hawaii
Authors: Showstack Randy
Published: May 2013

The daily mean concentration of carbon dioxide (CO2) in the atmosphere at Mauna Loa, Hawaii, hit 400.03 parts per million (ppm) on 9 May, marking the first time the concentration there has topped 400 ppm since measurements began at Mauna Loa in 1958, the U.S. National Oceanic and Atmospheric Administration (NOAA) announced on 10 May. NOAA scientists with the agency's Global Monitoring Division have made measurements of CO2 at the NOAA Mauna Loa Observatory since 1974.
White House issues Arctic strategy
Authors: Showstack Randy
Published: May 2013

The White House released its first‐ever National Strategy for the Arctic Region on 10 May. The strategy “is intended to position the United States to respond effectively to challenges and emerging opportunities arising from significant increases in Arctic activity due to the diminishment of sea ice and the emergence of a new Arctic environment,” the executive summary states.
NOAA draft research and development plan released
Authors: Showstack Randy
Published: May 2013

The U.S. National Oceanic and Atmospheric Administration (NOAA) has released a new draft version of its 5‐year research and development (R&D) plan for 2013–2017, Research and Development at NOAA: Environmental Understanding to Ensure America's Vital and Sustainable Future. The plan, which was announced in the Federal Register on 7 May, will chart a course for R&D in support of the agency's four long‐term goals of climate, weather, oceans, and coasts, and it will guide the agency's R&D activities over the next 5 years.
RADARSAT‐1 no longer operational
Authors: Showstack Randy
Published: May 2013

The Canadian Space Agency's workhorse RADARSAT‐1, the nation's first Earth observation satellite, is no longer operational, the agency announced on 9 May. The satellite, which launched in 1995, had experienced a technical anomaly in March that could not be resolved. RADARSAT‐2, launched in 2007, continues to provide users with data, and the agency is planning for the launch of the RADARSAT Constellation Mission of three satellites in 2018.
Urban Waters partnership expands
Authors: Showstack Randy
Published: May 2013

The Urban Waters Federal Partnership has expanded to include 11 new additions throughout the United States, bringing the number of sites in the program to 18, the White House Council on Environmental Quality (CEQ) announced on 10 May at a briefing in Grand Rapids, Mich.
Klaus Wyrtki (1925–2013)
Authors: Patzert William C. , Emery William J. , Meyers Gary A. , Lukas Roger
Published: May 2013

We bid a fond aloha to Klaus Wyrtki, a great scientist and a true friend and mentor to his many students and colleagues throughout the world. Wyrtki passed away peacefully on 5 February 2013, 2 days before his 88th birthday. Klaus, as he was known to most, was a longtime member of AGU and was elected a Fellow in 1982. In 1989, he received AGU's Maurice Ewing Medal.
Advancing Reflectometry
Authors: Garrison James L. , Larson Kristine M. , Burrage Derek
Published: May 2013

Reflectometry, a microwave remote‐sensing technique to extract geophysical data from scattered satellite transmissions, was first demonstrated using Global Navigation Satellite System (GNSS) reflections. Recently, reflectometry has been extended to the reutilization of digital communication satellite signals for Earth remote sensing, now referred to as “signals of opportunity.” This expands the application of reflectometry to most microwave bands that penetrate the Earth's atmosphere. GNSS+R 2012 provided an opportunity for engineers and Earth scientists to assess the state of the art, demonstrate new applications, and discuss potential missions.
Highlights From the 2012 Member Survey
Authors: Treby Jill
Published: May 2013

AGU conducted a member survey in November 2012 to collect data for comparison to the 2010 member survey and gather information regarding member opinions about AGU governance and changes in the AGU governance structure. Of the nearly 8000 members contacted, 1407 completed the survey, a total response rate of 17.7%.
Third Annual AGU Take Your Child to Work Day: Explorations in Earth and Space Science
Authors: Debeuneure Jalin , Adamec Bethany Holm
Published: May 2013

The third annual Take Your Child to Work Day was held 25 April 2013 at AGU headquarters. Nearly 25 children, grandchildren, and nieces and nephews of AGU staff members participated in the daylong activities.
High rates of nitrogen fixation in equatorial upwelling region
Authors: Balcerak Ernie
Published: May 2013

Surface waters in upwelling regions of the ocean are generally rich in nutrients. Scientists had thought that these areas would have low rates of nitrogen fixation because diazotrophs—microbes that convert nitrogen gas from the atmosphere into usable forms, such as ammonia—could use the nutrients in the water directly instead of having to fix nitrogen gas. However, researchers recently recorded high rates of nitrogen fixation in an upwelling region in the equatorial Atlantic.
Guiding future research on the Madden‐Julian Oscillation
Authors: Schultz Colin
Published: May 2013

Much as the recurrent variations of the El Niño–Southern Oscillation (ENSO) affect climate and drive strong interannual variability across the planet, the Madden‐Julian Oscillation (MJO)—a months‐long, semireliable cycle—affects everything from the Indian monsoon to Pacific hurricanes to North American snowfall. Unlike the better known ENSO, which is seen primarily as an interannual oscillation in equatorial Pacific Ocean surface ocean temperatures, MJO is characterized by a transient cycle in Indian Ocean and western Pacific atmospheric behavior—a semiregular shift in tropical convection and large‐scale atmospheric circulation patterns.
Predicting fire activity using terrestrial water storage data
Authors: Balcerak Ernie
Published: May 2013

High fire activity periods in the Amazon region can be predicted months in advance on the basis of water storage data, a new study shows. Chen et al. analyzed satellite observations of terrestrial water storage from the Gravity Recovery and Climate Experiment (GRACE) mission, along with satellite observations of fire activity from the Moderate Resolution Imaging Spectroradiometer (MODIS) mission. GRACE measures the Earth's gravity field by calculating the changes in the distance between two satellites as slight variations in density pull on one satellite more than the other. The gravity measurements provide information about the amount of groundwater or surface water in a given region.
A global map of the ocean's climate
Authors: Schultz Colin
Published: May 2013

Drawing on a massive set of ocean observations, Schmidtko et al. designed and built a map of the climate of the upper ocean, charting the regional properties in temperature and salinity for the global ocean. The authors’ map takes aspects of ocean physics into account to better detail the ocean's properties from the surface down to where the pressure hits around 1950 decibars. The authors’ map has a horizontal grid resolution of 0.5 degree and covers all the Earth's oceans, from the Southern Ocean to the Arctic Ocean.
Characterizing the Moon's radiation environment
Authors: Balcerak Ernie
Published: May 2013

The radiation environment near the Moon could be damaging to humans and electronics on future missions. To characterize this potentially hazardous environment, the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) on board the Lunar Reconnaissance Orbiter mission, which orbits at 50 kilometers above the Moon's surface, measures the radiation that would be absorbed by either electronic parts or human tissue behind the shielding of a spacecraft.
Extensive Antarctic campaign finds cold bias in satellite records
Authors: Schultz Colin
Published: May 2013

Advances in satellite sensing have now made it possible to track changes in the world's most remote locations. Over the Antarctic continental interior, the vast majority of profiles of atmospheric temperature are provided by satellite remote sensing, making proper calibration of the satellite observational equipment and analysis algorithms particularly important. However, the hostile environmental conditions in regions such as the Antarctic make it difficult or even dangerous to conduct the in‐the‐field observations needed to calibrate and validate the satellite observations.
Three‐dimensional mapping of airflow over dunes
Authors: Balcerak Ernie
Published: May 2013

Similar to the way a river, flowing across Earth's surface, influences sediment transport and shaping of the landscape, coastal winds, which flow over dunes, affect how the dune shapes evolve and how sand is transported along the coast. Wind flow over dunes has been extensively studied, but in most cases, that research has been two‐dimensional and focused on straight dunes with smooth slopes and no vegetation or other features that might affect how airflow separates at the crest of the dune.
First global analysis of the hum produced by body waves
Authors: Schultz Colin
Published: May 2013

Driven by oceanic and atmospheric waves and turbulence and their interactions with the surface and the sea floor, the Earth produces a low‐frequency song known as “seismic hum,” a regular background hiss of seismic waves. By applying a mathematical technique known as cross‐correlation interferometry to the observations of seismic hum produced by surface seismic waves, researchers have been able to better understand the structure and composition of the surface layers of the Earth's crust. Recently, researchers have started applying cross‐correlation interferometry to seismic body waves, waves that travel through the Earth rather than along the surface to study the properties of Earth's mantle and core.
Multiple Structural Coloring of Silk‐Fibroin Photonic Crystals and Humidity‐Responsive Color Sensing
Authors: Diao Ying Ying , Liu Xiang Yang , Toh Guoyang William , Shi Lei , Zi Jian
Published: May 2013

In the biological world, numerous creatures such as butterflies, insects, and birds have exploited photonic structures to produce bicolor reflections with important biofunctions in addition to unique brilliant structural coloration. Although the mimicking of bistructural color reflection is possible, the fabrication involves a process of combined layer deposition techniques, which is complicated and less flexible. Here, a bistructural color mimicking, based on silk fibroin, is reported using a simple and inexpensive self‐assembly method. Silk‐fibroin inverse opals with different spectral positions of bistructural color reflection (i.e., ultraviolet and visible peaks, ultraviolet and near infrared peaks, and visible and near infrared peaks) are obtained by simply controlling their lattice constants. Furthermore, the inline and continuous tuning of the peak positions of bistructural color reflection can be achieved by the humidity‐induced cyclic contraction of silk fibroin. The potential applications of silk‐fibroin photonic structures in eco‐dying and multifunctional silk fabrics are also demonstrated.
Inwards Interweaving of Polymeric Layers within Hydrogels: Assembly of Spherical Multi‐Shells with Discrete Porosity Differences
Authors: Pan Houwen Matthew , Beyer Sebastian , Zhu Qingdi , Trau Dieter
Published: May 2013

The unique inwards interweaving morphology of polyamines and polyacids within agarose hydrogels that leads to the formation of striated shells with different porosities within the spherical scaffold is reported. Microcompartments with sophisticated structures are commonly used in drug delivery, tissue engineering, and other biomedical applications. However, a method capable of producing well‐defined, multiporous shells within a single compartment is still lacking. By the alternating deposition of polyallylamine (PA) and polystyrenesulfonic acid (PSS) in 1‐butanol, at equal mass ratios, multiple levels of porosity are generated within an agarose microsphere. Each level of porosity is represented by a well‐defined, concentric shell of interweaving PA and PSS layers. The number, thickness, and porosity of the striated shells can be easily controlled by varying the number of PA/PSS bilayers and the polymer concentration, respectively. The feasibility of utilizing this morphology for the assembly of a multi‐shell porous spherical scaffold is validated by trapping different molecular weight dextrans within different regions of porosity. The unique interaction of polyacids and polyamines in hydrogels represents a facile and inexpensive approach to the development of intricate scaffold architectures.
Scalable One‐Step Wet‐Spinning of Graphene Fibers and Yarns from Liquid Crystalline Dispersions of Graphene Oxide: Towards Multifunctional Textiles
Authors: Jalili Rouhollah , Aboutalebi Seyed Hamed , Esrafilzadeh Dorna , Shepherd Roderick L. , Chen Jun , Aminorroaya‐Yamini Sima , Konstantinov Konstantin , Minett Andrew I. , Razal Joselito M. , Wallace Gordon G.
Published: May 2013

Key points in the formation of liquid crystalline (LC) dispersions of graphene oxide (GO) and their processability via wet‐spinning to produce long lengths of micrometer‐dimensional fibers and yarns are addressed. Based on rheological and polarized optical microscopy investigations, a rational relation between GO sheet size and polydispersity, concentration, liquid crystallinity, and spinnability is proposed, leading to an understanding of lyotropic LC behavior and fiber spinnability. The knowledge gained from the straightforward formulation of LC GO “inks” in a range of processable concentrations enables the spinning of continuous conducting, strong, and robust fibers at concentrations as low as 0.075 wt%, eliminating the need for relatively concentrated spinning dope dispersions. The dilute LC GO dispersion is proven to be suitable for fiber spinning using a number of coagulation strategies, including non‐solvent precipitation, dispersion destabilization, ionic cross‐linking, and polyelectrolyte complexation. One‐step continuous spinning of graphene fibers and yarns is introduced for the first time by in situ spinning of LC GO in basic coagulation baths (i.e., NaOH or KOH), eliminating the need for post‐treatment processes. The thermal conductivity of these graphene fibers is found to be much higher than polycrystalline graphite and other types of 3D carbon based materials.
Topological Control of Porous Silicon Photonic Crystals by Microcontact Printing
Authors: Ruminski Anne M. , Barillaro Giuseppe , Secret Emilie , Huang Winnie D. , Potocny Andrea , Carion Ulysse , Wertans Charles , Sailor Michael J.
Published: May 2013

Free‐standing, uniformly wrinkled multilayered photonic crystals are prepared in porous Si by conformal electrochemical etch of a highly doped p++ type Si wafer that is pre‐shaped with periodic grooves. The grooves are prepared by first microcontact printing a parallel line of oligomeric polydimethylsiloxane and then electrochemically etching the patterned wafer. The etch proceeds anisotropically, with the resist‐covered regions etching more slowly than the resist‐free regions. The grooved substrate is then etched using a sinusoidal current density waveform, generating a porosity‐modulated photonic crystal (rugate filter) that is conformal with the grooves. This porous multilayer is then removed, resulting in a freestanding nanostructure with a corrugated topological modulation in the x–y plane and a rugated porosity modulation in the z‐direction. In addition to the resonant photonic reflectance signature from the porosity‐modulated rugate filter (along the z direction), the structures display optical diffraction in transmission from the x–y plane due to the spatially modulated grooves. The silicon wafer that remains after removal of the porous multilayer still contains a rippled surface, allowing the process to be repeated without additional microcontact printing. Six generations of freestanding, three‐dimensional diffraction gratings are produced from a single wafer and only one initial patterning step.
Reversible Three‐Dimensional Focusing of Visible Light with Ultrathin Plasmonic Flat Lens
Authors: Chen Xianzhong , Huang Lingling , Mühlenbernd Holger , Li Guixin , Bai Benfeng , Tan Qiaofeng , Jin Guofan , Qiu Cheng‐Wei , Zentgraf Thomas , Zhang Shuang
Published: May 2013

Metasurfaces with interfacial phase discontinuities provide a unique platform for manipulating light propagation both in free space and along a surface. Three‐dimensional focusing of visible light is experimentally exhibited as a bi‐functional phenomenon by controlling the radial orientation of identical plasmonic dipoles, generating a desired phase profile along the interface. With this technique, the in‐plane and out‐of‐plane refractions are manipulated by an ultrathin flat lens such that a beam can be focused into a 3D spot either in a real or virtual focal plane, which can be reversed via manipulation of the circularly polarized status of the incident light. Both the inverted real image and the upright virtual image of an arbitrary object are experimentally demonstrated using the same flat lens in the visible range, which paves the way towards robust application of phase discontinuity devices.
A Nonlinear Switching Mechanism in Quantum Dot and Metallic Nanoparticle Hybrid Systems
Authors: Cox Joel D. , Singh Mahi R. , von Bilderling Catalina , Bragas Andrea V.
Published: May 2013

Second harmonic generation and two‐photon photoluminescence in CdS quantum dots near metallic nanoparticles are theoretically and experimentally investigated. A control laser field is applied to the hybrid system, which couples with the surface plasmons of the metal nanoparticles. The polarized metal nanoparticles then interact with the quantum dots through dipole–dipole interactions, which enhances the intensity of the second harmonic signal from the quantum dots. The density matrix method is used to numerically simulate the second harmonic signal emitted by the quantum dots. It is found that the enhancement of the second harmonic signal can be switched on and off by changing the control field intensity. Alternatively, the second harmonic signal enhancement can be turned on or off by changing the frequency of the control field. This is an interesting finding which can be used to fabricate nonlinear all optical nanoswitching devices from hybrid systems.
Surface Plasmon‐Enhanced Third Harmonic Generation from Gold–Polymer Hybrid Plasmonic Crystal
Authors: Chen Shumei , Wong Winghan , Pun Yuebun , Cheah Kokwai , Li Guixin
Published: May 2013

Surface plasmon resonance generates strong light localization in plasmonic nanostructures, which has been used to enhance various nonlinear optical processes. However, the nonlinear optical efficiency of metal itself is usually not high enough and this limits the potential application. Hence, if a material with a large nonlinear optical response can be embedded within the plasmonic nanostructure, it would be possible to generate larger nonlinear optical response. In this work, an organic conjugated polymer with large third harmonic generation efficiency is integrated into a gold/ITO‐based plasmonic crystal. Large surface plasmon‐enhanced third harmonic generation in the metal–polymer hybrid plasmonic crystal is experimentally observed. The integration of organic polymer into plasmonic crystal opens a new avenue to develop novel nonlinear optical plasmonic devices.
State of the art in the determination of the fine structure constant: test of Quantum Electrodynamics and determination of
Authors: Bouchendira Rym , Cladé Pierre , Guellati‐Khélifa Saida , Nez Francois , Biraben Francois
Published: May 2013

The fine structure constant α has a particular status in physics. Its precise determination is required to test the quantum electrodynamics (QED) theory. The constant α is also a keystone for the determination of other fundamental physical constants, especially the ones involved in the framework of the future International System of units. This paper presents Paris experiment, where the fine structure constant is determined by measuring the recoil velocity of a rubidium atom when it absorbs a photon. The impact of the recent improvement of QED calculations of the electron moment anomaly and the recent measurement of the cesium atom recoil at Berkeley will be discussed. The opportunity to provide a precise value of the ratio between the Planck constant and the atomic mass constant will be investigated.
Effects of different ionic liquids on the electrospinning of a polyacrylonitrile polymer solution
Authors: Cheng Wei , Yu Qi , Qiu Zhiming , Yan Yurong
Published: May 2013

Additives have been proven to be useful in improving electrospinnability and controlling fiber morphology through the modification of solution properties, including the conductivity, viscosity, and surface tension. In this study, the effects of adding small amounts of four different types of ionic liquids [i.e., 1‐butyl‐3‐methylimidazolium chloride (C4MIMCl), 1‐dodecyl‐3‐methylimidazolium chloride (C12MIMCl), 1‐ethyl‐3‐methylimidazolium bromide (C2MIMBr), and 1‐ethyl‐3‐methylimidazolium phosphate (C2MIM)3PO4] on the solution properties, electrospinning process, and characteristics of polyacrylonitrile (PAN) were investigated. The results show that the solution conductivities significantly increased with the addition of different ionic liquids with concentrations varying from 0.1 to 1.0 wt %, and the tendency depended on the structures of the ionic liquids. (C2MIM)3PO4 showed the highest conductivity value; this was followed by C2MIMBr, C4MIMCl, and C12MIMCl. The ionic liquids formed visible crystals; this made the fiber surfaces rough, and some fiber segments underwent partial aggregation. A regular varying tendency between the minimum mean diameter of the PAN/ionic liquid fibers and the structure of the ionic liquid was found. The PAN/N,N‐dimethylformamide (DMF)/(C2MIM)3PO4 solution showed the highest conductivity among the four systems with different ionic liquids added, and the thinnest minimum diameter of the PAN/(C2MIM)3PO4 fibers appeared with a relatively low ionic liquid concentration of 0.25 wt %, whereas the PAN/DMF/C12MIMCl solution had the lowest conductivity, and the minimum mean diameter of PAN/C12MIMCl fibers appeared at a relatively high ionic liquid concentration of 0.8 wt %. Although the conductivity of the PAN/DMF/C2MIMBr solution was higher than that of the PAN/DMF/C4MIMCl solution, the minimum mean diameters of the PAN/C2MIMBr and PAN/C4MIMCl fibers appeared at the same ionic liquid concentration of 0.5 wt % because of the similar ionic activities of C2MIMBr and C4MIMCl. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2359–2368, 2013
Preparation, characterization, and release behavior of ceftiofur‐loaded gelatin‐based microspheres
Authors: Hao Zhihui , Wu Haoting , Hao Lihua , Zhao Yongda , Ding Zhaopeng , Yang Fenfang , Qu Baohan
Published: May 2013

Drug‐loaded microspheres prepared from biomacromolecules have received considerable interest. In this article, we report a facile method for preparing ceftiofur‐loaded gelatin‐based microspheres for controlled release. We investigated the effects of factors, including the rotational speed, concentration of surfactant, concentration of gelatin, and ratio of water to oil (W/O), on the morphologies of gelatin microspheres and obtained the optimized conditions; for a typical average diameter of about 15 μm, these were 1000 rpm, a concentration of span 80 of 2.0%, a gelatin concentration of 20%, and a W/O of 1:20. Gelatin microspheres loaded with ceftiofur, ceftiofur‐Na, and ceftiofur‐HCl were prepared and characterized by scanning electron microscopy and laser light scattering. In vitro release studies were carefully performed for microspheres prepared with different crosslinker contents, loaded with different drugs, and blended with chitosan. The loaded ceftiofur showed an obviously longer release time compared with pure ceftiofur powder. A higher content of crosslinker led to a longer release time, but when the content reached 5%, the microspheres had a significantly cracked surface. The results also indicate that the blending of a small amount of chitosan could greatly prolong the release time. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2369–2376, 2013
Stability of a chitosan layer deposited onto a polyethylene surface
Authors: Pâslaru Elena , Fras Zemljic Lidija , Bračič Matej , Vesel Alenka , Petrinić Irena , Vasile Cornelia
Published: May 2013

A two‐step procedure was applied to obtain antimicrobial films; this procedure involved a corona treatment of the polyethylene (PE) surface and its chemical activation with 1‐ethyl‐3‐[3‐dimethylaminopropyl] carbodiimide hydrochloride and N‐hydroxysuccinimide, and this led to the covalent bonding of chitosan on the PE surface. Electrochemical methods were used to investigate the stability of the deposited chitosan layer. The potentiometric and polyelectrolyte titrations showed that some amount of chitosan desorbed faster from the surface until equilibrium was reached and also that the grafted chitosan layer was more stable than the physically adsorbed one. The chitosan immobilized on the PE surface exhibited the expected antibacterial activity when tested against three bacteria, which included two Gram‐negative bacteria, Salmonella enteritidis and Escherichia coli, and one Gram‐positive bacterium, Listeria monocytogenes. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2444–2457, 2013
Development of magnetic fabrics with tunable hydrophobicity
Authors: Ho Thu , Ghochaghi Negar , Tepper Gary
Published: May 2013

Polystyrene (PS) fiber mats incorporating iron (Fe) particles were fabricated by electrospinning and the hydrophobicity of the resulting magnetic fabrics was investigated with and without an applied magnetic field. The results show that the hydrophobicity increases in the presence of a magnetic field and the hysteresis in the advancing/receding contact angle decreases in the presence of a magnetic field. It is also shown that the contact angle and hysteresis increase with decreasing fiber diameter. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2352–2358, 2013
Preparation and characterization of bamboo fiber‐graft‐lauryl methacrylate and its composites with polypropylene
Authors: Chen Qinhui , Mao Xinggong , Xue Hanyu , Deng Yi , Lin Jinhuo
Published: May 2013

In this study, lauryl methacrylate grafted onto bamboo fibers (BF‐g‐LM) was prepared to improve the interfacial compatibility between hydrophilic bamboo fibers (BFs) and hydrophobic plastic. The lauryl methacrylate (LM) was initiated by benzoxyl peroxide (BPO) and grafted onto BFs via a free‐radical chain‐transfer reaction. LM was grafted onto BFs with ether bonds, and differential scanning calorimetry indicated that the ether pyrolysis of BF‐g‐LM occurred at 280°C. The optimum preparation conditions were obtained as follows: 0.30 g of pretreated bamboo flour was immersed in 0.225 mol/L LM. The reaction was then initiated by 0.025 mol/L BPO, and this reaction was sustained for 4 h at 80°C. BF‐g‐LM served as coupling agent between the BFs and the polypropylene (PP) matrix, as shown by scanning electron microscopy analysis. The elongation at break of the BF/PP composites with BF‐g‐LM increased to two times compared to that of the BF/PP composites without BF‐g‐LM. The impact strength and maximum deflection also increased to 75 and 580%, respectively. In conclusion, BF‐g‐LM is a promising coupling agent that can be used in BF‐reinforced thermoplastic composites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2377–2382, 2013
Gas permeability of thin dense films from polymer blend of thermoplastic elastomer and polyolefin
Authors: Uenishi Masamoto , Fukushima Noriaki , Teramachi Masashi , Mizuta Masahiko , Kamo Jun , Tsuru Toshinori
Published: May 2013

Stretched thin films composed of a thermoplastic elastomer, a polystyrene‐block‐poly(ethylene butylene)‐block‐polystyrene triblock copolymer (SEBS), and polyolefins, poly(ethylene‐co‐ethylacrylate) and poly(ethylene‐co‐propylene), were obtained by blow‐molding, uniaxial stretching, and cooling to room temperature and the gas permeability of the stretched films was investigated. When the as‐blown annealed film was subjected to uniaxial stretching in the machine direction, PO2 and PN2 increased with an increase in the stretching ratio K and approached a constant value at high stretching ratios. In addition, PO2/PN2 decreased gradually with K and approached a value of 2.95–3.0. The reason for this unique gas permeation behavior is that the molecular mobility of poly(ethylene butylene) chains in a direction normal to the film increases and reaches an equilibrium state at around K = 4.5. The change in gas permeability of the stretched films can be explained using a deformation model for the SEBS matrix. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39386.
Large‐scale equal‐proportional amplification bio‐replication of shark skin Based on solvent‐swelling PDMS
Authors: Chen Huawei , Zhang Xin , Zhang Deyuan , Pan Junfeng , Hagiwara Ichiro
Published: May 2013

Shark skin has attracted worldwide attention on its superior drag reduction, so‐called shark skin effect. Such marvelous function of shark skin, in particular, is in part related to complicated micro‐riblets. As the creation of natural evolution, micro‐riblets of shark skin act out desirable drag reduction only within range of swimming speed. Over past few years, bio‐replication approach which takes the shark skin as replica template to 1 : 1 transfer surface morphology has been widely applied for drag reduction. However, if application environment remarkably differs from living environment, the drag reduction function is attenuated or even becomes adverse, i.e., the surface structure nonadjustable to ambient environment is obstacle to widespread application of bio‐replication. In this paper, large‐scale equal‐proportional amplification bio‐replication approach is presented to adjust the micro‐riblets of shark skin by taking solvent‐swelling polymer as replica mould. Solvent‐swelling property of polymer is investigated by controlling its swelling ratio to make natural surface function adapting to various application environment. Apart from higher replication accuracy about 95%, experiments show that about 140% solvent‐swelling ratio is achieved at one‐time amplification, and translation of drag reduction peak of natural surface function form living environment to various application environments is ensured by successive large‐scale equal‐proportional bio‐replications. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2383–2389, 2013