bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of minimally invasive parathyroidectomy techniques in sporadic primary hyperparathyroidism: systematic review
Authors: Gracie D , Hussain S S M
Published: October 2011

The past two decades have seen rapidly changing attitudes towards the surgical management of primary hyperparathyroidism. Advances in localisation techniques and confidence with endoscopy have led to the development of numerous minimally invasive parathyroidectomy approaches, including open minimal incision and endoscopic and video-assisted parathyroidectomy.

This paper systematically reviews the evidence for these methods to determine: (1) whether these new, minimally invasive techniques are comparable to conventional bilateral neck exploration methods in terms of success and complication rate; and (2) if they are comparable, which technique is likely to be best for cosmesis, patient safety and patient satisfaction.

A search of the Medline, Cochrane Reviews and Scopus databases was conducted, using a defined list of search parameters. Abstracts were compared against inclusion and exclusion criteria, before the full text was sought and analysed for data. The evidence from each study was then assessed, based on study quality, and a recommendation made based on the level of evidence available.

There is level 1b evidence that minimally invasive surgery is comparable to bilateral neck exploration in terms of efficacy and complication rates. This paper recommends that the treatment of choice for solitary adenoma (in most healthcare centres) should be open minimal incision parathyroidectomy, due to advantages in operative duration, learning curve and cost-effectiveness.
Incidence of non-infectious ‘acute mastoiditis’ in children
Authors: Kontorinis G , Psarommatis I , Karabinos C , Iliodromiti Z , Tsakanikos M
Published: October 2011

Objective:

The temporal bone may be the first involved site in cases of systemic disease, and may even present with acute, mastoiditis-like symptomatology. This study aimed to evaluate the incidence of such non-infectious ‘acute mastoiditis’ in children.

Materials and methods:

Retrospective chart review of 73 children admitted to a tertiary referral centre for acute mastoiditis.

Results:

In 71 cases (97.3 per cent), an infectious basis was identified. In the majority of cases (33 of 73; 45 per cent), the responsible bacteria was Streptococcus pneumoniae. However, histopathological studies revealed a non-infectious underlying disease (myelocytic leukaemia or Langerhans' cell histiocytosis) in two atypical cases (2.7 per cent).

Conclusion:

‘Acute mastoiditis’ of non-infectious aetiology is a rare but real threat for children, and a challenging diagnosis for otologists. A non-infectious basis should be suspected in every atypical, persistent or recurrent case of acute mastoiditis.
The same as it never was? Uncertainty and the changing contours of international law
Authors: KESSLER OLIVER
Published: October 2011

International law has changed significantly since the end of the Cold War. As long as the international was thought to be populated by sovereign states predominantly, international law was conceived of as a means for peaceful dispute settlement. That is: the reference to state sovereignty not only divided public from private international law, but structured most of public international law itself; from the very definition of and associated rights and duties to the attribution of responsibility. With the emergence of the post-national constellation, a reduction of law to questions of states' practices is increasingly problematic. At the same time, the post-national constellation denotes more than just a structural shift in the world polity. It challenges established dogmas rooted in an individualistic philosophy of science and thereby calls for a different understanding of how the world is (made) known. What uncertainty has to offer is the provision of a different vocabulary detached from the state through which we can reconsider some changes in international law.
Developing contour surfaces of manipulators with specified dexterities
Authors: Tsai K. Y. , Lin P. J. , Yu H. Y.
Published: October 2011

Dexterity and workspace are two of the most important design criteria in developing manipulators. This paper presents algorithms for developing contour surfaces with specified dexterities and evaluating the area of the surfaces or the volume of the enclosed regions. The obtained results can be utilized to evaluate the dexterity and the rate of change of dexterity. Any closed curve or surface can be used to determine the singularity-free workspace of a manipulator with better dexterity. The proposed algorithms can be employed to study the dexterity and singularity-free workspace of 3-DOF manipulators and 4-DOF redundant serial manipulators. The contour surfaces in some subspaces of 6-DOF manipulators can also be investigated.
High-Speed Atomic Force Microscopy Enables New Applications
Authors: Mininni Lars , Slade Andrea , Kindt Johannes , Hu Shuiqing
Published: October 2011

Atomic force microscopy (AFM) is one of the most powerful and dynamic methods for performing nanoscale imaging and materials characterization, enabling scientists and researchers to attain atomic resolution and measure nano-mechanical material properties in-situ, all while requiring minimal sample preparation. In spite of these clear advantages, user adoption of AFM has been limited by the technique's slow imaging speed as compared to light microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). However, recent advances in AFM technology have increased AFM imaging speeds by over an order of magnitude, opening up a wide range of new applications while greatly improving the user experience.
Elaborate Helmets are Actually Appendages!
Authors: Carmichael Stephen W.
Published: October 2011

Of the winged insects, adults have one or two pairs of wings. During the past 250 million years of insect evolution, there have been no exceptions to this. In a fascinating study, Benjamin Prud'homme, Caroline Minervino, Mélanie Hocine, Jessica Cande, Aïcha Aouane, Héloïse Dufour, Victoria Kassner, and Nicolas Gompel may have found something resembling an exception.
Advantages of Simultaneous Imaging Using an Atomic Force Microscope Integrated with an Inverted Light Microscope
Authors: Johnson W. Travis
Published: October 2011

Atomic Force Microscopy (AFM) permits measurements on biological samples below the limits of light microscopy resolution under physiological environments and other controlled conditions. Consequently, AFM has become an increasingly valuable technique in cell biology. One of the most exciting advances in AFM instrumentation has been its integration with the light microscope. This permits investigators to take advantage of the power and utility of light microscopy and scanning probe microscopy simultaneously. In combining a light microscope with an AFM, scanner components must be specifically designed so that they do not adversely impact the light microscope's optical imaging capabilities. For example, an AFM-ILM (inverted light microscope) hybrid system should be fully compatible with the highest quality, off-the-shelf 0.50–0.55 NA numerical aperture (NA) OEM objectives and condensers.
Calendar
Authors: Webster Paul
Published: October 2011

Following is a list of microscopy related meetings and courses. The editors would greatly appreciate input to this list via the electronic submission form under “events/other microscopy events” at the MSA webpage: www.microscopy.org. We will gladly add hypertext links to the notice on the web and insert a listing of the meeting in the next issue.
Keeping It Clean!
Authors: Levesque Tom
Published: October 2011

Microscopists are looking at smaller features every day, and the potential to see artifacts that degrade or obscure these small features has never been greater. Because many current microscopy techniques are conducted in vacuum environments, residual gaseous components in the vacuum chamber may have substantial effects on the data collected. This brief review will describe some approaches to keep the quality of data collected in electron and ion-beam microscopes at the highest possible levels. In short, we will attempt to “keep it clean.”
Kinder- und Jugendpsychiatrie in Europa
Authors: Herpertz-Dahlmann Beate
Published: October 2011

Child and Adolescent Psychiatry in Europe – Quo vadis? Activities of the European Society for Child and Adolescent Psychiatry (ESCAP)
Relative importance of impervious area, drainage density, width function, and subsurface storm drainage on flood runoff from an urbanized catchment
Authors: Ogden Fred L. , Raj Pradhan Nawa , Downer Charles W. , Zahner Jon A.
Published: October 2011

The literature contains contradictory conclusions regarding the relative effects of urbanization on peak flood flows due to increases in impervious area, drainage density and width function, and the addition of subsurface storm drains. We used data from an urbanized catchment, the 14.3 km2 Dead Run watershed near Baltimore, Maryland, USA, and the physics‐based gridded surface/subsurface hydrologic analysis (GSSHA) model to examine the relative effect of each of these factors on flood peaks, runoff volumes, and runoff production efficiencies. GSSHA was used because the model explicitly includes the spatial variability of land‐surface and hydrodynamic parameters, including subsurface storm drains. Results indicate that increases in drainage density, particularly increases in density from low values, produce significant increases in the flood peaks. For a fixed land‐use and rainfall input, the flood magnitude approaches an upper limit regardless of the increase in the channel drainage density. Changes in imperviousness can have a significant effect on flood peaks for both moderately extreme and extreme storms. For an extreme rainfall event with a recurrence interval in excess of 100 years, imperviousness is relatively unimportant in terms of runoff efficiency and volume, but can affect the peak flow depending on rainfall rate. Changes to the width function affect flood peaks much more than runoff efficiency, primarily in the case of lower density drainage networks with less impermeable area. Storm drains increase flood peaks, but are overwhelmed during extreme rainfall events when they have a negligible effect. Runoff in urbanized watersheds with considerable impervious area shows a marked sensitivity to rainfall rate. This sensitivity explains some of the contradictory findings in the literature.
Malaria: New Medicines for its Control and Eradication
Authors: Wells Timothy N. C. , Gutteridge Winston E.
Published: October 2011

Malaria is one of the most widespread infectious diseases of our time. About 40% of the world's population live in countries where the disease is endemic and around 243 million people suffer from the disease every year. The vast majority of the cases are in children under five, and often amongst the poorest populations. New generations of medicines will always be needed, since there is always the threat of resistance emerging. Recent years have seen a renaissance in the search for new antimalarials. Advances in genome-based target identification, and also in whole parasite screening technologies means that more tools are now available for drug discovery. Increased understanding of the importance of emerging markets and of corporate social responsibility means that the pharmaceutical industry is now heavily supporting malaria drug discovery projects. Financial support from governments and from private foundations is a key element here though: malaria drug discovery will never be self-sustaining. Recent years have seen a call for a new strategy to help drive the eradication of malaria. This will need new types of medicines, moving beyond simple control of the disease, to prevention of transmission and elimination of host reservoirs. Since these medicines will take over a decade to discover and develop, it is important to have a clear view on the ultimate target product profiles that we are searching to address. Success could see the relegation of malaria to text books of tropical medicine and parasitology.
Semisynthetic Artemisinin and Synthetic Peroxide Antimalarials
Authors: Tilley Leann , Charman Susan A. , Vennerstrom Jonathan L.
Published: October 2011

Since the discovery of the endoperoxide sesquiterpene lactone artemisinin, numerous second-generation semisynthetic artemisinins and synthetic peroxides have been prepared and tested for their antimalarial properties. Using a case-study approach, we describe the discovery of the investigational semisynthetic artemisinins artelinic acid (8) and artemisone (9), and the structurally diverse synthetic peroxides arteflene (10), fenozan B07 (11), arterolane (12), PA1103/SAR116242 (13), and RKA182 (14).
The Medicinal Chemistry of Eradication: Hitting the Lifecycle where it Hurts.
Authors: Jeremy Nicholas Burrows  , Robert Edward Sinden
Published: October 2011

Historically, antimalarial drug discovery efforts have predominantly focused on curing patients by delivering new medicines that kill the asexual blood stages of the infection. Within an eradication agenda curing patients is only the start, however. Blocking transmission of the parasite from infected humans to the mosquito and vice versa, and thus disrupting the parasite lifecycle, will become a critical need. Whilst insecticides, bed nets and vaccines can all play a part in the prevention of disease and blocking of transmission, new medicines are urgently required that act beyond the blood stages. Prosecuting drug discovery projects in this arena is a developing paradigm made feasible only due to the ongoing advances in technology and understanding. Interestingly, the parasite numbers outside the asexual blood stages are significantly lower and offer compelling targets for intervention. This chapter addresses the medicinal chemistry of eradication: hitting the lifecycle where it hurts.
Drug Discovery for Kinetoplastid Diseases
Authors: Jacobs Robert T.
Published: October 2011

The past decade has seen a renewed commitment to the discovery of new agents for diseases caused by the kinetoplastid parasites Trypanosoma brucei (human African trypanosomiasis), Leishmania spp. (visceral and cutaneous leishmaniasis) and Trypanosoma cruzi (Chagas disease). The renaissance of research has been driven by the completion of sequencing of the genome of these organisms, the emergence of philanthropic organizations and increased collaboration between academic, industrial and government scientists through public-private partnerships, thus enabling and promoting integrated drug discovery and development programs. This chapter describes a breadth of approaches being taken, which range from discovery of new compound classes such as benzoxaboroles, nitroheterocycles and metal-based antiparasitics from whole-cell screening assays to exploration of drug candidates such as diamidines, protease inhibitors and inhibitors of polyamine metabolism which act on individual biochemical targets essential to parasite survival. Key to many of these efforts, regardless of approach or pathway, has been to find compounds which exhibit selectivity for cidal effects on the parasite(s) relative to the mammalian host. Future development of these new molecules toward clinically useful drug candidates is dependent upon further integration of medicinal chemistry, parasitology, pharmacokinetics and toxicology to meet the stringent regulatory requirements for registration of new treatments of these neglected diseases.
Current Approaches to Tuberculosis Drug Discovery and Development
Authors: Mitton-Fry Mark J. , Hanna Debra
Published: October 2011

Since the first streptomycin trials for TB in 1944, anti-TB drug discovery research has been inspired by the hope of developing a cure for this dread disease. Pre-clinical TB research efforts are complex given the varied metabolic states of the bacteria (coinciding with active versus persistent infection), long doubling time of the MTB pathogen, the requirement for BSL-3 facilities, and labor/time-intensive methodologies for evaluating compound efficacy. Anti-TB drug development paradigms are also challenging, given the duration of clinical trials and the complexity of combination regimen evaluation. For these reasons, it is important to use the most current pre-clinical and clinical tools for the efficient selection and advancement of NMEs. This chapter reviews the current discovery and development paradigms of 5 novel anti-TB agents, relating those efforts to current tools and methodologies to enable effective decision making. These agents include the nitroimidazo derivatives (PA-824 and OPC-67683), the diarylquinoline TMC207 (R207910), the diamine SQ109, and a novel oxazolidinone, PNU-100480. These agents highlight the exciting opportunities in the coming decade to positively impact the global TB health problem. New agents can be discovered and developed through efficient and coordinated discovery and development approaches alongside effective partnerships with governments in the developed and developing world.
Diarrhoeal Diseases
Authors: Brown, David
Published: October 2011

Diarrhoea is the second leading cause of death in children globally. Just under 9 million children aged under 5 years died in 2008 and 1.5 million of these deaths were due to diarrhoea. It kills more children than AIDS, malaria, and measles combined. Including adult deaths, diarrhoeal diseases killed over 2.5 million people in 2009, according to the World Health Organization (WHO).

Funding for prevention and treatment has been insufficient. Neonatal and childhood deaths from diarrhoeal diseases account for nearly 20% of all deaths in children under 5 years of age, yet only 4.4% of global health funding is allocated to diarrhoeal disease research and development.

A 2009 report from UNICEF titled Diarrhoea: why children are still dying and what can be done outlined a seven-point plan for comprehensive diarrhoea control. The prevention package includes vaccination versus rotavirus and measles; promotion of early and exclusive breastfeeding and vitamin A supplementation; promotion of hand-washing with soap; improved water quantity and quality, including treatment and safe storage of household water; and promotion of community-wide sanitation. The treatment package includes fluid replacement to prevent dehydration (Oral Rehydration Salts) and zinc supplements.

Looking further forward, new cholera vaccines are becoming available, with active research at an earlier stage on vaccines versus typhoid, dysentery and E. coli. Antisecretory drugs are at various stages of development. If these prove compatible with ORS use, the combination would be a significant advance. Calcium-activated chloride channel blockers may provide additional therapeutic opportunities in the longer term.
Managing the HIV Epidemic in the Developing World – Progress and Challenges
Authors: Ryst Elna van der , Palmer Michael J , Vuuren Cloete van
Published: October 2011

The identification of the first few cases of acquired immune-deficiency syndrome (AIDS) and HIV in the early 1980s heralded the start of a global epidemic of unprecedented proportions. It soon became clear that the developing world, especially sub-Saharan Africa, is bearing the brunt of the epidemic, thereby further increasing the public health impact of the disease.

Since the initial cases of AIDS and the discovery of HIV, significant progress has been made in understanding the epidemiology and pathogenesis of HIV and combating the infection. The discovery and development of multiple drugs to treat HIV infection, thereby turning the disease into a chronic manageable condition, less than 30 years after the discovery of the causative virus, is undoubtedly one of the greatest achievements of modern medical science.

However, there is no room for complacency, as much remains to be done in the fields of both prevention and treatment of HIV. Key ongoing needs are new drugs to treat drug-resistant virus, management of long-term complications of antiretroviral therapy, management of HIV infection in the context of ageing, and the treatment of HIV-induced chronic immune activation and its consequences. Large numbers of patients in the developing world do not yet have access to even basic antiretroviral therapy or are sub-optimally managed. Further research on the optimal and most cost-effective strategies for managing HIV infection in resource-limited settings is urgent. It is up to those engaged in research to continue to lead the way to resolving these remaining issues.
Conceptual design and analysis of ITM oxy-combustion power cycles
Authors: Mancini N. D. , Mitsos A.
Published: October 2011

Hybridized ion transport membrane power cycles and detailed plant-level analysis using physics-based models and new performance metrics.
Ubiquitin-specific protease 4 (USP4) targets TRAF2 and TRAF6 for deubiquitination and inhibits TNFα-induced cancer cell migration
Authors: Xiao Ning , Li Hui , Luo Jian , Wang Rui , Chen Haiquan , Chen Jiquan , Wang Ping
Published: October 2011

TRAF [TNF (tumour necrosis factor)-receptor-associated factor] 2 and 6 are essential adaptor proteins for the NF-κB (nuclear factor κB) signalling pathway, which play important roles in inflammation and immune response. Polyubiquitination of TRAF2 and TRAF6 is critical to their activities and functions in TNFα- and IL (interleukin)-1β-induced NF-κB activation. However, the regulation of TRAF2 and TRAF6 by deubiquitination remains incompletely understood. In the present study, we identified USP (ubiquitin-specific protease) 4 as a novel deubiquitinase targeting TRAF2 and TRAF6 for deubiquitination. We found that USP4 specifically interacts with TRAF2 and TRAF6, but not TRAF3. Moreover, USP4 associates with TRAF6 both in vitro and in vivo, independent of its deubiquitinase activity. The USP domain is responsible for USP4 to interact with TRAF6. Ectopic expression of USP4 inhibits the TRAF2- and TRAF6-stimulated NF-κB reporter gene and negatively regulates the TNFα-induced IκBα (inhibitor of NF-κBα) degradation and NF-κB activation. Knockdown of USP4 significantly increased TNFα-induced cytokine expression. Furthermore, we found that USP4 deubiquitinates both TRAF2 and TRAF6 in vivo and in vitro in a deubiquitinase activity-dependent manner. Importantly, the results of the present study showed that USP4 is a negative regulator of TNFα- and IL-1β-induced cancer cell migration. Taken together, the present study provides a novel insight into the regulation of the NF-κB signalling pathway and uncovers a previously unknown function of USP4 in cancer.
Language Development and Fragile X Syndrome
Authors: Abbeduto Leonard , Sterling Audra
Published: October 2011

Fragile X syndrome (FXS) is the leading inherited cause of intellectual disability, with a behavioral profile of relative cognitive strengths and weaknesses, as well as a heightened probability of various forms of psychopathology. In this article, the authors review the language strengths and areas of challenge in children with FXS, as well as consider the contributions of the language learning environment to language acquisition. This article concludes with considerations of research findings to clinical practice.
Interpretation of the photoelectron spectra of superalkali species: Li3O and Li3O−
Authors: Zein S. , Ortiz J. V.
Published: October 2011

The present paper deals with the interpretation of the photoelectron spectrum of the Li3O−. After several failed attempts to attribute all of the observed peaks in the experimental spectrum to anionic species, neutral species were considered assuming a sequential two-photon absorption mechanism. We find that only two of the six observed peaks can be attributed to photodetachments and that all other observed features can be assigned to ionizations from the ground and excited states of the neutral. Nuclear distributions other than three lithium atoms surrounding the oxygen are not likely to be stable. The interpretation of the experimental peak located at about 1.2 eV remains challenging. It can either be attributed to the second electron detachment (involving the HOMO −1 orbital) energy from the anion's triplet C2v state or to higher excited states (involving HOMO +10, 11, 12… orbitals) of the neutral species. Furthermore, we have examined the influence of vibrational displacements on the location of the observed peaks. We find that this effect is smaller than 0.05 eV and, therefore, must be considered as negligible.
Comment on “Study of dielectric relaxations of anhydrous trehalose and maltose glasses” [J. Chem. Phys. 134, 014508 (2011)]
Authors: Kaminski K. , Wlodarczyk P. , Paluch M.
Published: October 2011

Very recently Kwon et al. [H.-J. Kwon, J.-A. Seo, H. K. Kim, and Y. H. Hwang, J. Chem. Phys. 134, 014508 (2011)] published an article on the study of dielectric relaxation in trehalose and maltose glasses. They carried out broadband dielectric measurements at very wide range of temperatures covering supercooled liquid as well as glassy state of both saccharides. It is worth to mention that authors have also applied a new method for obtaining anhydrous glasses of trehalose and maltose that enables avoiding their caramelization. Four relaxation processes were identified in dielectric spectra of both saccharides. The slower one was identified as structural relaxation process the next one, not observed by the others, was assigned as Johari-Goldstein (JG) β-relaxation, while the last two secondary modes were of the same nature as found by Kaminski et al. [K. Kaminski, E. Kaminska, P. Wlodarczyk, S. Pawlus, D. Kimla, A. Kasprzycka, M. Paluch, J. Ziolo, W. Szeja, and K. L. Ngai, J. Phys. Chem. B 112, 12816 (2008)]. In this comment we show that the authors mistakenly assigned the slowest relaxation process as structural mode of disaccharides. We have proven that this relaxation process is an effect of formation of thin layer of air or water between plate of capacitor and sample. The same effect can be observed if plates of capacitor are oxidized. Thus, we concluded that their slowest mode is connected to the dc conduction process while their β JG process is primary relaxation of trehalose and maltose.
Ultrafast non-adiabatic dynamics of methyl substituted ethylenes: The π3s Rydberg state
Authors: Wu Guorong , Boguslavskiy Andrey E. , Schalk Oliver , Schuurman Michael S. , Stolow Albert
Published: October 2011

Excited state unimolecular reactions of some polyenes exhibit localization of their dynamics at a single ethylenic double bond. Here we present studies of the fundamental photophysical processes in the ethylene unit itself. Combined femtosecond time-resolved photoelectron spectroscopy (TRPES) and ab initio quantum chemical calculations was applied to the study of excited state dynamics in cis-butene, trans-butene, trimethylethylene, and tetramethylethylene, following initial excitation to their respective π3s Rydberg states. The wavelength dependence of the π3s Rydberg state dynamics of tetramethylethylene was investigated in more detail. The π3s Rydberg to ππ* valence state decay rate varies greatly with substituent: the 1,2-di- and tri-methyl substituted ethylenes (cis-butene, trans-butene, and trimethylethylene) show an ultrafast decay (∼20 fs), whereas the fully methylated tetramethylethylene shows a decay rate of 2 to 4 orders of magnitude slower. These observations are rationalized in terms of topographical trends in the relevant potential energy surfaces, as found from ab initio calculations: (1) the barrier between the π3s state and the ππ* state increases with increasing methylation, and (2) the π3s/ππ* minimum energy conical intersection displaces monotonically away from the π3s Franck-Condon region with increasing methylation. The use of systematic methylation in combination with TRPES and ab initio computation is emerging as an important tool in discerning the excited state dynamics of unsaturated hydrocarbons.
Magnifying lens for 800 MeV proton radiography
Authors: Merrill F. E. , Campos E. , Espinoza C. , Hogan G. , Hollander B. , Lopez J. , Mariam F. G. , Morley D. , Morris C. L. , Murray M. , Saunders A. , Schwartz C. , Thompson T. N.
Published: October 2011

This article describes the design and performance of a magnifying magnetic-lens system designed, built, and commissioned at the Los Alamos National Laboratory (LANL) for 800 MeV flash proton radiography. The technique of flash proton radiography has been developed at LANL to study material properties under dynamic loading conditions through the analysis of time sequences of proton radiographs. The requirements of this growing experimental program have resulted in the need for improvements in spatial radiographic resolution. To meet these needs, a new magnetic lens system, consisting of four permanent magnet quadrupoles, has been developed. This new lens system was designed to reduce the second order chromatic aberrations, the dominant source of image blur in 800 MeV proton radiography, as well as magnifying the image to reduce the blur contribution from the detector and camera systems. The recently commissioned lens system performed as designed, providing nearly a factor of three improvement in radiographic resolution.
Epitaxial graphene three-terminal junctions
Authors: Göckeritz Robert , Pezoldt Jörg , Schwierz Frank
Published: October 2011

We report on the fabrication and characterization of graphene three-terminal junctions with nanometer dimensions. The devices have been realized in epitaxial graphene on semi-insulating silicon carbide. All current-carrying device parts consist of graphene resulting in all-carbon structures. Pronounced voltage rectification and frequency multiplication have been observed at room temperature.
Jordan algebras and orthogonal polynomials
Authors: Tsujimoto Satoshi , Vinet Luc , Zhedanov Alexei
Published: October 2011

We illustrate how Jordan algebras can provide a framework for the interpretation of certain classes of orthogonal polynomials. The big −1 Jacobi polynomials are eigenfunctions of a first order operator of Dunkl type. We consider an algebra that has this operator (up to constants) as one of its three generators and whose defining relations are given in terms of anticommutators. It is a special case of the Askey-Wilson algebra AW(3). We show how the structure and recurrence relations of the big −1 Jacobi polynomials are obtained from the representations of this algebra. We also present ladder operators for these polynomials and point out that the big −1 Jacobi polynomials satisfy the Hahn property with respect to a generalized Dunkl operator.
Combined optical and acoustical method for determination of thickness and porosity of transparent organic layers below the ultra-thin film limit
Authors: Rodenhausen K. B. , Kasputis T. , Pannier A. K. , Gerasimov J. Y. , Lai R. Y. , Solinsky M. , Tiwald T. E. , Wang H. , Sarkar A. , Hofmann T. , Ianno N. , Schubert M.
Published: October 2011

Analysis techniques are needed to determine the quantity and structure of materials composing an organic layer that is below an ultra-thin film limit and in a liquid environment. Neither optical nor acoustical techniques can independently distinguish between thickness and porosity of ultra-thin films due to parameter correlation. A combined optical and acoustical approach yields sufficient information to determine both thickness and porosity. We describe application of the combinatorial approach to measure single or multiple organic layers when the total layer thickness is small compared to the wavelength of the probing light. The instrumental setup allows for simultaneous in situ spectroscopic ellipsometry and quartz crystal microbalance dynamic measurements, and it is combined with a multiple-inlet fluid control system for different liquid solutions to be introduced during experiments. A virtual separation approach is implemented into our analysis scheme, differentiated by whether or not the organic adsorbate and liquid ambient densities are equal. The analysis scheme requires that the film be assumed transparent and rigid (non-viscoelastic). We present and discuss applications of our approach to studies of organic surfactant adsorption, self-assembled monolayer chemisorption, and multiple-layer target DNA sensor preparation and performance testing.
Laser-locked, continuously tunable high resolution cavity ring-down spectrometer
Authors: Pan H. , Cheng C.-F. , Sun Y. R. , Gao B. , Liu A.-W. , Hu S.-M.
Published: October 2011

A continuous-wave cavity ring-down spectrometer with sub-MHz precision has been built using the sideband of a frequency stabilized laser as the tunable light source. The sideband is produced by passing the carrier laser beam through an electro-optic modulator (EOM) and then selected by a short etalon on resonance. The carrier laser frequency is locked to a longitude mode of a thermo-stabilized Fabry-Perot interferometer (FPI) with a long-term absolute frequency stability of 0.2 MHz (5 × 10−10). Broad and precise spectral scanning is accomplished, respectively, by selecting a different longitudinal mode of the FPI and by tuning the radio-frequency driving the EOM. The air broadened water absorption line at 12 321 cm−1 was studied to test the performance of the spectrometer.
Extremely high absolute internal quantum efficiency of photoluminescence in co-doped GaN:Zn,Si
Authors: Reshchikov M. A. , Willyard A. G. , Behrends A. , Bakin A. , Waag A.
Published: October 2011

We report on the fabrication of GaN co-doped with silicon and zinc by metalorganic vapor phase epitaxy and a detailed study of photoluminescence in this material. We observe an exceptionally high absolute internal quantum efficiency of blue photoluminescence in GaN:Zn,Si. The value of 0.93±0.04 has been obtained from several approaches based on rate equations.
Metamaterial polarization spectral filter: Isolated transmission line at any prescribed wavelength
Authors: Zheludev N. I. , Plum E. , Fedotov V. A.
Published: October 2011

We demonstrate that a narrowband spectral filter with a ripples-free isolated transmission peak and wide acceptance angle can be constructed exploiting polarization properties of a metal film patterned on the subwavelength scale. Its transmission band can be engineered to be anywhere from the visible to microwaves.
Chemical reactions modulated by mechanical stress: Extended Bell theory
Authors: Konda Sai Sriharsha M. , Brantley Johnathan N. , Bielawski Christopher W. , Makarov Dmitrii E.
Published: October 2011

A number of recent studies have shown that mechanical stress can significantly lower or raise the activation barrier of a chemical reaction. Within a common approximation due to Bell [Science 200, 618 (1978)], this barrier is linearly dependent on the applied force. A simple extension of Bell's theory that includes higher order corrections in the force predicts that the force-induced change in the activation energy will be given by –FΔR – ΔχF2/2. Here, ΔR is the change of the distance between the atoms, at which the force F is applied, from the reactant to the transition state, and Δχ is the corresponding change in the mechanical compliance of the molecule. Application of this formula to the electrocyclic ring-opening of cis and trans 1,2-dimethylbenzocyclobutene shows that this extension of Bell's theory essentially recovers the force dependence of the barrier, while the original Bell formula exhibits significant errors. Because the extended Bell theory avoids explicit inclusion of the mechanical stress or strain in electronic structure calculations, it allows a computationally efficient characterization of the effect of mechanical forces on chemical processes. That is, the mechanical susceptibility of any reaction pathway is described in terms of two parameters, ΔR and Δχ, both readily computable at zero force.
Photoelectron spectroscopy of the molecular anions, Li3O− and Na3O−
Authors: Wang Di , Graham Jacob D. , Buytendyk Allyson M. , Bowen Kit H.
Published: October 2011

The molecular anions, Li3O− and Na3O− were produced by laser vaporization and studied via anion photoelectron spectroscopy. Li3O− and Na3O− are the negative ions of the super-alkali neutral molecules, Li3O and Na3O. A two-photon process involving the photodetachment of electrons from the Li3O− and Na3O− anions and the photoionization of electrons from the resulting Li3O and Na3O neutral states was observed. The assignment of the Li3O− photoelectron spectrum was based on computational results provided by Zein and Ortiz [J. Chem. Phys. 135, 164307 (2011)]10.1063/1.3636082.
Fabrication of glass micro-cavities for cavity quantum electrodynamics experiments
Authors: Roy Arpan , Barrett Murray D.
Published: October 2011

We report a process for fabricating high quality, defect-free spherical mirror templates suitable for developing high finesse optical Fabry-Perot resonators. The process utilizes the controlled re-flow of borosilicate glass and differential pressure to produce mirrors with 0.3 nm surface roughness. The dimensions of the mirrors are in the 0.5–5 mm range making them suitable candidates for integration with on-chip neutral atom and ion experiments where enhanced interaction between atoms and photons is required. Cavities constructed with these mirror templates are well suited to quantum information applications such as single photon sources and atom-photon entanglement.
A New Synthetic Protocol for One-Pot Preparations of 5-Halo-1,4-disubstituted-1,2,3-triazoles
Authors: Li Lingjun , Li Yanyan , Li Ran , Zhu Anlian , Zhang Guisheng
Published: October 2011

In this paper, a new synthetic protocol for one-pot preparations of 5-halo-1,4-disubstituted-1,2,3-triazoles is provided by rational combination of a CuI catalyzed azide–alkyne cycloaddition (CuAAC) reaction and an oxidative halogenation reaction. CuI- N-chlorosuccinimide (NCS) and CuBr-NCS reaction systems are developed, respectively, for effective preparations of 5-iodo-1,4-disubstituted-1,2,3-triazoles and 5-bromo-1,4-disubstituted-1,2,3-trizoles under mild conditions with a high tolerance of various sensitive groups.
Nitrile Oxide 1,3-Dipolar Cycloaddition by Dehydration of Nitromethane Derivatives Under Continuous Flow Conditions
Authors: Brasholz Malte , Saubern Simon , Savage G. Paul
Published: October 2011

Aliphatic nitrile oxides were generated in situ, by dehydration of terminal nitro compounds, and reacted with dipolarophiles using continuous flow techniques to afford substituted isoxazolines. The yields of cycloadducts were comparable with traditional flask-based reactions but reaction times were much shorter. In-line scavenger cartridges conveniently removed by-products and unreacted reagents to give almost pure crude products. The process was demonstrated up to gram scale.
Differences in ball speed and accuracy of tennis groundstrokes between elite and high‐performance players
Authors: Landlinger Johannes , Stöggl Thomas , Lindinger Stefan , Wagner Herbert , Müller Erich
Published: October 2011

The main aim of this study was to identify and compare ball speed and hitting accuracy of forehand and backhand groundstrokes between ATP professionals (elite) and high‐performance youth players when shots were played cross‐court and down the line to a target square. Six elite and seven high‐performance tennis players volunteered to participate in the study. A Doppler‐radar device and a digital video camera, operating at 120 frames per second, were used to measure ball speed and accuracy of forehand and backhand groundstrokes in the respective situation (cross‐court and down the line). The results of 1040 measured groundstrokes indicate that the ball speed of the forehand and the backhand ground stroke was higher in the elite group when analysing (1) all valid shots, (2) the six fastest shots, and (3) the six most accurate shots (all P < 0.05). In addition, all players achieved a higher forehand speed compared with their backhand when balls were directed cross‐court (P < 0.01). The participants demonstrated similar ability when considering accuracy of their groundstrokes (P > 0.05). However, a group difference for accuracy was identified when considering the six fastest forehand shots (P<0.05), and the forehand cross‐court stroke was played more accurately than the backhand cross‐court stroke by both groups (valid shots and six most accurate shots, P<0.05). Moreover, there was no evidence that players who impacted the ball faster were any less accurate than those who impacted the ball more slowly. Analyses for participants actually revealed a negative correlation between ball speed and mean radial error (accuracy) for the backhand down the line (r= − 0.77, P<0.01). According to the results of this study, ball speed seems to be the determining factor that separates elite from sub‐elite tennis players.
Motor coordination, physical activity and fitness as predictors of longitudinal change in adiposity during childhood
Authors: Lopes VÍtor P , Maia José A. R. , Rodrigues Luis P , Malina Robert
Published: October 2011

The purpose of this study was to examine the influence of motor coordination (MC), physical fitness (PF) and physical activity (PA) on the development of subcutaneous adiposity in a sample of children followed longitudinally from 6 to 10 years of age. Participants were 142 girls and 143 boys. Height, weight, and the triceps and subscapular skinfolds were measured annually between the ages of 6 and 10 years. PA was estimated with the Godin–Shephard questionnaire. MC was evaluated with the Körperkoordination Test für Kinder (KTK) test battery, and PF was assessed with four Fitnessgram tests: curl‐ups (CU), push‐ups (PU), trunk‐lifts (TL) and one mile run/walk (MRW). Hierarchical linear modelling with MC, PF items and PA as predictors of the sum of two skinfolds (SKF) was used. The results showed that boys and girls differed significantly in SKF at baseline (girls: 19.7 mm; boys: 16.6 mm). Three PF items (CU, PU and MRW) and MC had a positive influence on SKF. For each unit improvement in CU, PU, MRW and MC, SKF was reduced by 0.06, 0.04, 0.06 and 0.12 mm, respectively. In conclusion, motor coordination, muscular strength and endurance, and aerobic endurance attenuated the accumulation of subcutaneous adipose tissue during childhood.
Spin-wave band gaps created by rotating square rods in two-dimensional magnonic crystals
Authors: Yang Hui , Yun Guohong , Cao Yongjun
Published: October 2011

Absolute spin-wave band gaps can be substantially opened and tuned by rotating noncircular rods in two-dimensional magnonic crystals. Spin-wave band structures of two-dimensional magnonic crystals composed of Fe (EuO) square rods squarely arranged in a EuO (Fe) matrix are numerically calculated using the plane-wave method. The results show that it is possible to increase the width of the band gaps or to create band gaps by rotating the noncircular rods. For the system of EuO rods in Fe matrix, the largest absolute spin-wave gap in the structure of square rods is 227% of the size of that in the corresponding structure of circular rods. Such an approach may open up a new scope for engineering band gaps of two-dimensional magnonic crystals.
Characterization of nanocrystalline nitrogen-containing titanium oxide obtained by N2/O2/Ar low-field helicon plasma sputtering
Authors: Sarra-Bournet C , Haberl B , Charles C , Boswell R
Published: October 2011

TiO2 and nitrogen-containing TiO2 thin films were deposited on glass and silicon wafer substrates using a helicon-assisted reactive plasma sputtering process in a gas mixture of Ar/O2/N2. The growth mechanism, chemical composition and crystalline structure were probed by x-ray photoelectron spectroscopy, x-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopy. The presence of nitrogen in the film induces the formation of some Ti3+ defects states, which introduces oxygen vacancies in the TiO
x
N
y
structure. It is also observed that nitrogen substitution selectively hinders the formation of the crystalline rutile phase and promotes the growth of a polycrystalline anatase phase film. Moreover, the film exhibits a red-shift in light absorption from UV to visible spectrum as a function of the nitrogen doping. This work shows that crystalline TiO2 thin films can be obtained with a low temperature process and also shows that using nitrogen can control the desired crystalline structure.
Improved resistance switching in ZnO-based devices decorated with Ag nanoparticles
Authors: Shi L , Shang D S , Chen Y S , Wang J , Sun J R , Shen B G
Published: October 2011

ZnO is especially attractive among the materials showing resistance switching because of its excellent properties such as light emitting and transparency for visible light. Unfortunately, the resistance switching in a ZnO-based device is usually unstable. By dispersing Ag particles of size ∼20 nm at the electrode–ZnO interface, we significantly improved the resistance uniformity, set/reset repeatability of Ag–ZnO–Pt devices. Conducting atomic force microscope analysis revealed the appearance of micro-regions where resistance switching, with an improved stability, is more easily triggered. It is suggested that Ag particles act as seeds for conducting filaments, leading to depressed randomness and reduced diameter of the conducting paths.
Incorporation of electron tunnelling phenomenon into 3D Monte Carlo simulation of electrical percolation in graphite nanoplatelet composites
Authors: Baniassadi M , Safdari M , Ghazavizadeh A , Garmestani H , Ahzi S , Grácio J , Ruch D
Published: October 2011

The percolation threshold problem in insulating polymers filled with exfoliated conductive graphite nanoplatelets (GNPs) is re-examined in this 3D Monte Carlo simulation study. GNPs are modelled as solid discs wrapped by electrically conductive layers of certain thickness which represent half of the electron tunnelling distance. Two scenarios of ‘impenetrable’ and ‘penetrable’ GNPs are implemented in the simulations. The percolation thresholds for both scenarios are plotted versus the electron tunnelling distance for various GNP thicknesses. The assumption of successful dispersion and exfoliation, and the incorporation of the electron tunnelling phenomenon in the impenetrable simulations suggest that the simulated percolation thresholds are lower bounds for any experimental study. Finally, the simulation results are discussed and compared with other experimental studies.
Red, green, blue and white light upconversion emission in Yb3+/Tm3+/Ho3+ co-doped tellurite glasses
Authors: Desirena H , De la Rosa E , Salas P , Meza O
Published: October 2011

Several Yb3+/Tm3+/Ho3+ co-doped transparent TeO2–ZnO–Na2O–Yb2O3–Ho2O3–Tm2O3 glasses were prepared and luminescence properties were characterized. Simultaneous red, green and blue (RGB) emission were obtained after excitation at 970 nm. Colour emission was tuned from multicolour to white light with colour coordinate (0.32, 0.33) matching very well with the white reference (0.33, 0.33). Changes in colour emission were obtained by varying the intensity ratios between RGB bands that are strongly concentration dependent because of the interaction of co-dopants. The colour tunability, high quality of white light and high intensity of the emitted signal make these transparent glasses excellent candidates for applications in solid-state lighting.