bluuebunny/crossref_metadata_2025 huggingface dataset:
Recent Development in Synthetic Strategies for Oseltamivir Phosphate
Authors: Shibasaki Masakatsu , Kanai Motomu , Yamatsugu Kenzo
Published: March 2011

Recent developments in synthetic strategies toward an important anti‐influenza drug, oseltamivir phosphate, are discussed. The importance of the drug further increased after the influenza A (H1N1) pandemic in 2009 and the emergence of the highly virulent avian influenza H5N1, which might eventually acquire the ability to spread between humans. Currently, the drug is produced in an industrial process of 11 chemical steps starting from (–)‐shikimic acid, whose availability is limited due to the massive demand of the drug. Thus, many chemists have been working to develop alternative synthetic processes to produce this important drug starting from readily available materials using environmentally benign, operationally safe, and cost‐effective methods. Synthetic efforts made by each group of chemists are described in this review article. The development of novel synthetic methodologies and novel reactions has had a great impact on the efficient syntheses of functional molecules, such as drugs like oseltamivir phosphate.
A Computational Framework for Magnetic Polyoxometalates and Molecular Spin Structures: CONDON 2.0
Authors: Speldrich Manfred , Schilder Helmut , Lueken Heiko , Kögerler Paul
Published: March 2011

The emergence of increasingly complex molecular magnets, driven in particular by polyoxometalate chemistry, requires theoretical tools to accurately model and understand their magnetic phenomena. At the same time the unambiguous verification of model Hamiltonians remains a challenge, tied to factors ranging from available independent experimental data sets to available computation resources. Focusing on several recent examples for magnetically functionalized polyoxometalates and polynuclear coordination complexes, we demonstrate the recent developments of CONDON 2.0 that aim to address these issues, and suggest measurement protocols that will aid our multi‐parameter computational approach.
Hybrid Polyoxometalates: Merging Organic and Inorganic Domains for Enhanced Catalysis and Energy Applications
Authors: Berardi Serena , Carraro Mauro , Sartorel Andrea , Modugno Gloria , Bonchio Marcella
Published: March 2011

Organic–inorganic hybrids based on polyoxometalate scaffolds(POMs) are a unique class of molecular metal‐oxides featuring a composite surface, whereby the merging of complementary domains stimulates new functions and enhances performances. The interaction between the organic and inorganic components can be designed via covalent and/or non‐covalent strategies, yielding novel molecular systems with key applications in catalysis and materials science. Selected examples of such a rewarding approach will be illustrated, including the synthesis of tailored POM‐based catalysts, and their application in homogeneous systems and on electrocatalytic surfaces for water splitting and renewable energy production.
A PVA/PVP hydrogel for human lens substitution: Synthesis, rheological characterization, and in vitro biocompatibility
Authors: Leone Gemma , Consumi Marco , Greco Giuseppe , Bonechi Claudia , Lamponi Stefania , Rossi Claudio , Magnani Agnese
Published: March 2011

To overcome opacification and absence of accommodation of human lens substitutes a new poly(vinyl alcohol) (PVA)/poly(N‐vinyl‐2‐ pyrrolidinone) (PVP) based hydrogel (PPS31075) was realised. The Infrared Spectroscopy and the mechanical spectra confirmed the successful occurrence of crosslinking reaction. The rheological analysis pointed out a behavior comparable with that of young human lens in terms of complex shear modulus and accommodation capability. Further analysis in terms of optical properties, water content measurements, diffusion coefficient, cytotoxicity, and human capsular cell adhesion confirmed the applicability of such a hydrogel as potential human lens substitute. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
Improved bio‐implant using ultrafast laser induced self‐assembled nanotexture in titanium
Authors: Bush Joshua R. , Nayak Barada K. , Nair Lakshmi S. , Gupta Mool C. , Laurencin Cato T.
Published: March 2011

The most successful metal implant materials currently have relatively smooth surfaces on the micron size scale, with most failures occurring after only 10 years. To move beyond this limiting time scale, texturing methods have been developed to modify the metal surface to enhance integration of the implant directly with surrounding bone. A flexible single‐step ultrafast‐laser texturing process has been developed that results in a surface texture that exhibits micron scale peaks and troughs with superimposed submicron and nano‐scale features. The textured titanium samples remain completely hydrophilic with no measurable contact angle even after several weeks in normal atmosphere. An increase in mesenchymal stem cell number is observed over that on an untreated control titanium surface. Extensive formation of cellular bridges by stromal cells between pillars shows the favorable response of differentiated cells to the surface and the promotion of their attachment. Expression of the alkaline phosphatase and osteocalcin genes in human bone marrow cells were seen to increase on the textured surface. The development of this single‐step method for creating micron, submicron, and nano‐scale surface texture directly on metals makes a significant contribution to the goal of improving the integration and life span of joint replacement implants. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
The effect of radiation dose on the tensile and impact toughness of highly cross‐linked and remelted ultrahigh‐molecular weight polyethylenes
Authors: Huot J Caitlin , Van Citters Douglas W. , Currier John H. , Collier John P.
Published: March 2011

Several highly cross‐linked and remelted ultrahigh‐molecular weight polyethylenes (UHMWPE) were introduced in 1998 as bearing materials for orthopaedic implants to achieve superior wear performance. However, gamma radiation and the subsequent postirradiation thermal treatment are associated with decreased mechanical properties such as ductility, toughness, and fatigue strength compared to noncross‐linked materials. The purpose of this study was (a) to characterize the toughness (tensile and impact) of highly cross‐linked and remelted UHMWPE of varying doses (0–255 kGy) and (b) determine whether a correlation exists between both toughness measures. As radiation dose increased, tensile toughness and impact toughness were shown to decrease in a nonlinear fashion; largely a result of the decrease in ductility, which was also observed. Impact toughness and tensile toughness were also found to be strongly correlated to one another (R2 = 0.97). © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.
A lentiviral vector pseudotype suitable for vaccine development
Authors: Lopes Luciene , Dewannieux Marie , Takeuchi Yasuhiro , Collins Mary K.
Published: March 2011

Background

Lentiviral vectors (LV) are promising vaccines because they transduce dendritic cells (DC) in vivo. To translate LV vaccines into clinical trials, bulk production will be necessary. The present study aimed to find a suitable envelope for LV vaccine production from stable packaging cells because the commonly used vesicular stomatitis virus envelope (VSV‐G) is cytotoxic.

Methods

The envelope from Ross river virus (RRV) was selected. It can infect mouse and human cells, allowing testing in animals before clinical translation. We used VSV‐G for comparison. Vectors produced with each envelope were titred on human 293T cells and mouse 3T3 cells.

Results

RRV‐pseudotyped LV (RRV‐LV) infected mouse myeloid DC in culture and immunized mice. An approximately 50‐fold higher dose of RRV‐LV than VSV‐G‐LV was required to generate a similar T cell response. The RRV‐LV could also be used to infect human mDC and to prime a human T cell immune response.

Conclusions

RRV envelope is a suitable candidate to be used for the construction of an LV producer cell line. LV vaccines with RRV envelope can be tested in mice and in human immune cell cultures. The higher dose of RRV‐LV required for vaccine efficacy compared to VSV‐G‐LV will partly be offset by ease of production. Copyright © 2011 John Wiley & Sons, Ltd.
Scanning electron microscopic imaging of surface effects in desorption and nano‐desorption electrospray ionization
Authors: Kaftan Filip , Kofroňová Olga , Benada Oldřich , Lemr Karel , Havlíček Vladimír , Cvačka Josef , Volný Michael
Published: March 2011

Scanning electron microscopy was used to investigate rivulets that are formed on the analyzed surface during desorption electrospray ionization (DESI) experiment. Ferromagnetic nanoparticles added to the spray solvent in a form of colloid solution functioned as an additional surface probe. The existence of the rivulets was confirmed on glass and newly demonstrated on two different types of porous polytetrafluoroethylene (PTFE). The results show that in standard DESI set‐up the rivulets are arranged into very regular shapes. Same rivulets were obtained in DESI experiments without high voltage on the sprayer. However, no such rivulets or any other regular patterns were found on a surface in nano‐DESI (nanospray DESI without the carrier nebulizing gas) experiments. This indicates that symmetrical rivulets are created by the hydrodynamical rather than electrostatic forces. It was also demonstrated that blocking the rivulets by a simple physical barrier did not influence known surface charging effects. Copyright © 2011 John Wiley & Sons, Ltd.
How to identify and discriminate between the methyl quinates of chlorogenic acids by liquid chromatography–tandem mass spectrometry
Authors: Jaiswal Rakesh , Kuhnert Nikolai
Published: March 2011

The methyl esters of chlorogenic acids, methyl quinates, are widely distributed in plant materials and frequently appear as extraction artifacts in plant samples. This is the first time when liquid chromatography–tandem mass spectrometry methods have been used for the identification and characterization of the methyl quinates. For this purpose, methyl quinates of mono caffeoylquinic acids and mono feruloylquinic acids were synthesized as authentic standards. The methyl quinates of mono and diacyl chlorogenic acids have shown characteristic fragmentation pattern in their tandem mass spectra. MSn + 1 spectra of the methyl quinates of diacyl chlorogenic acids were identical to MSn spectra of mono acyl derivatives. These quinates do not produce any methyl quinate peak at m/z 205 if compared with quinic acid peak at m/z 191 in negative ion mode. In the MSn spectra of these quinates, cinnamic acid part or cinnamoyl part was detected as a base peak in negative ion mode. The retention time, order of elution and fragmentation pattern were completely different if compared with LC–MSn methods developed for chlorogenic acids. These LC–MSn methods have been applied for the identification and regioisomeric characterization of the methyl quinates of chlorogenic acids in maté tea and woodruff (Galium odoratum). Two methyl caffeoylquinates (2 and 4) were identified as methyl 3‐caffeoylquinate and methyl 5‐caffeoylquinate. Copyright © 2011 John Wiley & Sons, Ltd.
Differentiation of human kidney stones induced by melamine and uric acid using surface desorption atmospheric pressure chemical ionization mass spectrometry
Authors: Jia Bin , Ouyang Yongzhong , Sodhi Rana N. S. , Hu Bin , Zhang Tingting , Li Jianqiang , Chen Huanwen
Published: March 2011

Clinically obtained human kidney stones of different pathogenesis were dissolved in acetic acid/methanol solutions and then rapidly analyzed by surface desorption atmospheric pressure chemical ionization mass spectrometry (SDAPCI‐MS) without any desalination treatment. The mass spectral fingerprints of six groups of kidney stone samples were rapidly recorded in the mass range ofm/z50–400. A set of ten melamine‐induced kidney stone samples and nine uric acid derived kidney stone samples were successfully differentiated from other groups by principal component analysis of SDAPCI‐MS fingerprints upon positive‐ion detection mode. In contrast, the mass spectra recorded using negative‐ion detection mode did not give enough information to differentiate those stone samples. The results showed that in addition to the melamine, the chemical compounds enwrapped in the melamine‐induced kidney stone samples differed from other kidney stone samples, providing useful hints for studying on the formation mechanisms of melamine‐induced kidney stones. This study also provides useful information on establishing a MS‐based platform for rapid analysis of the melamine‐induced human kidney stones at molecular levels. Copyright © 2011 John Wiley & Sons, Ltd.
Selected reaction monitoring applied to proteomics
Authors: Gallien Sebastien , Duriez Elodie , Domon Bruno
Published: March 2011

Selected reaction monitoring (SRM) performed on triple quadrupole mass spectrometers has been the reference quantitative technique to analyze small molecules for several decades. It is now emerging in proteomics as the ideal tool to complement shotgun qualitative studies; targeted SRM quantitative analysis offers high selectivity, sensitivity and a wide dynamic range. However, SRM applied to proteomics presents singularities that distinguish it from small molecules analysis. This review is an overview of SRM technology and describes the specificities and the technical aspects of proteomics experiments. Ongoing developments aiming at increasing multiplexing capabilities of SRM are discussed; they dramatically improve its throughput and extend its field of application to directed or supervised discovery experiments. Copyright © 2011 John Wiley & Sons, Ltd.
Determination of triamcinolone in human plasma by a sensitive HPLC–ESI‐MS/MS method: application for a pharmacokinetic study using nasal spray formulation
Authors: César Isabela Costa , Byrro Ricardo Martins Duarte , de Santana e Silva Cardoso Fabiana Fernandes , Mundim Iram Moreira , de Souza Teixeira Leonardo , de Sousa Weidson Carlo , Gomes Sandro Antônio , Bellorio Karini Bruno , Brêtas Juliana Machado , Pianetti Gerson Antônio
Published: March 2011

A liquid chromatography–electrospray ionization tandem mass spectrometry (HPLC–ESI‐MS/MS) method for the quantitation of triamcinolone in human plasma after nasal spray application was developed and validated. Betamethasone was used as internal standard (IS). The analytes were extracted by a liquid–liquid procedure and separated on a Zorbax Eclipse XDB C18 column with a mobile phase composed of 2 mM aqueous ammonium acetate pH 3.2 and acetonitrile (55:45). Selected reaction monitoring was performed using the transitions m/z 435 → 415 and m/z 393 → 373 to quantify triamcinolone acetonide and betamethasone, respectively. Calibration curve was constructed over the range of 20–2000 pg/ml for triamcinolone acetonide. The lower limit of quantitation was 20 pg/ml. The mean RSD values were 4.6% and 5.7% for the intra‐run and inter‐run precision, respectively. The mean accuracy value was 98.5% and a recovery rate corresponding to 97.5% was achieved. No matrix effect was detected in the samples. The validated method was successfully applied to determine the plasma concentrations of triamcinolone acetonide in healthy volunteers, in a pharmacokinetic study with nasal spray formulation. Copyright © 2011 John Wiley & Sons, Ltd.
Dispersive liquid–liquid microextraction and gas chromatography–mass spectrometry determination of polychlorinated biphenyls and polybrominated diphenyl ethers in milk
Authors: Liu Xiujuan , Zhao Aijun , Zhang Aina , Liu Huanqiang , Xiao Wenjing , Wang Chengjun , Wang Xuedong
Published: March 2011

An effective multi‐residue pretreatment technique, solid‐phase extraction (SPE) combined with dispersive liquid–liquid microextraction (DLLME), was proposed for the trace analysis of 14 polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in milk samples using gas chromatography–mass spectrometry (GC‐MS). Interesting analytes in milk samples were extracted with hexane after protein precipitation. The hexane extracts were loaded on an LC‐Florisil column to isolate analytes from the milk matrix. The elutes were dried and dissolved in acetone, which was used as the disperser solvent in subsequent DLLME procedures. The effects of several important parameters on the extraction efficiency were evaluated. Under the optimized conditions, a linear relationship was obtained in the range of 0.02–10.00 μg/L (PCBs) and 0.5–100.00 μg/L (PBDEs). The LOD (S/N=3) and relative standard deviations (RSDs, n=5) for all analytes were 0.01–0.4 μg/L and 0.6–8.5%, respectively. The recoveries of the standards added to raw bovine milk samples were 74.0–131.8%, and the repeatabilities of the analysis results were 1.12–17.41%. This method has been successfully applied to estimating PCBs and PBDEs in milk samples.
Seasonal variation in nutritional characteristics of the diet of greater white‐fronted geese
Authors: Ely Craig R. , Raveling Dennis G.
Published: March 2011

We studied diet and habitat use of greater white‐fronted geese (Anser albifrons) from autumn through spring on their primary staging and wintering areas in the Pacific Flyway, 1979–1982. There have been few previous studies of resource use and forage quality of wintering greater white‐fronted geese in North America, and as a consequence there has been little empirical support for management practices pertaining to habitat conservation of this broadly distributed species. Observations of >2,500 flocks of geese and collections of foraging birds revealed seasonal and geographic variation in resource use reflective of changes in habitat availability, selection, and fluctuating physiological demands. Autumn migrants from Alaska arrived first in the Klamath Basin of California and southern Oregon, where they fed on barley, oats, wheat, and potatoes. Geese migrated from the Klamath Basin into the Central Valley of California in late autumn where they exploited agricultural crops rich in soluble carbohydrates, with geese in the Sacramento Valley feeding almost exclusively on rice and birds on the Sacramento–San Joaquin Delta primarily utilizing corn. White‐fronted geese began their northward migration in late winter, and by early spring most had returned to the Klamath Basin where 37% of flocks were found in fields of new growth cultivated and wild grasses. Cereal grains and potatoes ingested by geese were low in protein (7–14%) and high in soluble nutrients (17–47% neutral detergent fiber [NDF]), whereas grasses were low in available energy (47–49% NDF) but high in protein (26–42%). Greater white‐fronted geese are generalist herbivores and can exploit a variety of carbohydrate‐rich cultivated crops, likely making these geese less susceptible to winter food shortages than prior to the agriculturalization of the North American landscape. However, agricultural landscapes can be extremely dynamic and may be less predictable in the long‐term than the historic environments to which geese are adapted. Thus far greater white‐fronted geese have proved resilient to changes in land cover in the Pacific Flyway and by altering their migration regime have even been able to adapt to changes in the availability of suitable forage crops. © 2010 The Wildlife Society.
Factors affecting piping plover hatching success on Long Island, New York
Authors: Doherty Paul J. , Heath Julie A.
Published: March 2011

Low hatching success may limit progress towards reaching productivity goals for Atlantic Coast piping plover (Charadrius melodus) recovery, despite management strategies to protect eggs from predators and decrease human disturbance of birds on nests. We measured piping plover hatching success on Eastern Long Island beaches and identified the major causes of egg failure to better understand why eggs that were otherwise intact (not depredated or destroyed by tidal flooding) failed to hatch. We documented egg and nest fates, dissected contents of unhatched eggs to determine viability, and recorded human and predator activity near a subset of plover nests on Suffolk County Parks properties. The low hatching success we recorded (0.60) in 2006 and 2007 would require higher chick survival rates than are typically observed for piping plovers to meet recovery targets for productivity. Few eggs showed signs of poor viability and overall egg hatchability was comparable to other ground nesting birds. Most egg failure was due to either depredation at unexclosed nests or nest abandonment by adults. The best predictor of nest abandonment was the maximum number of red fox tracks (Vulpes vulpes) counted on nearby transects (β = −1.16, 95% CI: −2.0 to −0.3) and we found evidence that plovers abandoned eggs in response to predation risk (e.g., a fox circling a nest exclosure). Adults from abandoned nests may have deserted eggs or been depredated. In either case, intact and viable eggs were abandoned. Nest abandonment was not related to human activity near nests, which were buffered from human disturbance by symbolic string fencing. Our results suggest that depredation and nest abandonment (e.g., desertion or death of adults) due to predator disturbance, not human disturbance or poor egg viability, contributed to the low hatching success we recorded. Active predator removal in addition to modification of predator exclosure use and design may be necessary to prevent direct (egg depredation) and indirect (nest abandonment) negative effects of predators on hatching success. © 2010 The Wildlife Society.
Nest success of northern bobwhite on managed and unmanaged landscapes in southeast Iowa
Authors: Potter Lisa M. , Otis David L. , Bogenschutz Todd R.
Published: March 2011

Range‐wide declines in northern bobwhite populations (Colinus virginianus) have been attributed to concomitant loss of breeding habitat. Bobwhite management efforts to restore this habitat resource can be informed by empirical studies of associations between breeding success and multi‐scale habitat attributes. We compared bobwhite nest success in 2 southern Iowa landscapes as a function of microhabitat and landscape composition. Lake Sugema Fish and Wildlife Area (LSWA) was managed to promote bobwhite recruitment, and Harrisburg Township (HT) was an adjacent landscape dominated by private agricultural production. Survival rate modeling based on telemetry data provided evidence for age‐specific daily nest survival rate. Daily survival rates decreased as nest age increased, but the decline was more severe at HT. Nest survival at LSWA (S = 0.495, SE = 0.103) was nearly twice that on HT (S = 0.277, SE = 0.072). We found no evidence that habitat composition or spatial attributes within 210 m of a nest site significantly influenced nest success. Forb canopy at the nest site had a positive influence on nest success at HT but not at LSWA. We suggest nesting habitat with greater forb canopy cover will increase the opportunity for nesting success in landscapes with limited nesting habitat. © 2010 The Wildlife Society.
Estimating abundance of Sitka black‐tailed deer using DNA from fecal pellets
Authors: Brinkman Todd J. , Person David K. , Chapin F. Stuart , Smith Winston , Hundertmark Kris J.
Published: March 2011

Densely vegetated environments have hindered collection of basic population parameters on forest‐dwelling ungulates. Our objective was to develop a mark–recapture technique that used DNA from fecal pellets to overcome constraints associated with estimating abundance of ungulates in landscapes where direct observation is difficult. We tested our technique on Sitka black‐tailed deer (Odocoileus hemionus sitkensis) in the temperate coastal rainforest of Southeast Alaska. During 2006–2008, we sampled fecal pellets of deer along trail transects in 3 intensively logged watersheds on Prince of Wales Island, Alaska. We extracted DNA from the surface of fecal pellets and used microsatellite markers to identify individual deer. With genotypes of individual deer, we estimated abundance of deer with moderate precision (±20%) using mark–recapture models. Combining all study sites, we identified a 30% (SE = 5.1%) decline in abundance during our 3‐year study, which we attributed to 3 consecutive severe winters. We determined that deer densities in managed land logged >30 years ago (7 deer/km2, SE = 1.3) supported fewer deer compared to both managed land logged <30 years ago (10 deer/km2, SE = 1.5) and unmanaged land (12 deer/km2, SE = 1.4). Our study provides the first estimates of abundance (based on individually identified deer) for Sitka black‐tailed deer and the first estimates of abundance of an unenclosed ungulate population using DNA from fecal pellets. Our tool enables managers to accurately and precisely estimate the abundance of deer in densely vegetated habitats using a non‐invasive approach. © 2011 The Wildlife Society.
Comparison of techniques for sex determination of American martens
Authors: Belant Jerrold L. , Etter Dwayne R. , Friedrich Paul D. , Cosgrove Melinda K. , Williams Bronwyn W. , Scribner Kim T.
Published: March 2011

Accurate determination of sex in harvested species is critical for understanding demography and developing population models for management. We used genetic‐based sex identification to assess accuracy of external carcass and pelt examination at registration and maximum canine root area (MRA) to determine sex of American martens (Martes americana) trapped in the Upper Peninsula of Michigan, 2000–2004. Overall percent similarity between MRA and genetic‐based sex determination was 98.4% (n = 188). In contrast, only 84.6% (n = 421) of martens were similarly classified using external examination. For external examination, percent similarity to genetic‐based sex determination for juveniles (<1‐yr old) and adults (≥1‐yr old; Wald χ21 = 2.168, P = 0.141), as well as for males and females (Wald χ21 = 0.005, P = 0.946), was similar. We recommend MRA as a suitable technique for sex determination of martens; thus, marten sex and age (using cementum annuli counts) can be obtained from one lower canine tooth. We do not recommend use of external examination at registration to identify sex of martens without implementing additional quality assurance measures. © 2010 The Wildlife Society.
Modifications of traps to reduce bycatch of freshwater turtles
Authors: Bruce Bury R.
Published: March 2011

Mortality of freshwater turtles varies among types and deployments of traps. There are few or no losses in hoop or fyke traps set where turtles may reach air, including placement in shallows, addition of floats on traps, and tying traps securely to a stake or to shore. Turtle mortality occurs when traps are set deep, traps are checked at intervals >1 day, and when turtles are captured as bycatch. Devices are available that exclude turtles from traps set for crab or game fish harvest. Slotted gates in front of the trap mouth reduce turtle entry, but small individuals still may be trapped. Incidental take of turtles is preventable by integrating several designs into aquatic traps, such as adding floats to the top of traps so turtles may reach air or an extension tube (chimney, ramp) that creates an escape route. © 2010 The Wildlife Society.
Nest return times in response to static versus mobile human disturbance
Authors: Weston Michael A. , Ehmke Glenn C. , Maguire Grainne S.
Published: March 2011

We delivered standardized stimuli to incubating hooded plovers (Thinornis rubricollis) to examine the influence of human movement on disruption of incubation. The probability of plovers returning to nests within 60 min was higher in our treatment that mimicked mobile (e.g., walking) humans (85.7%) than in our treatment that mimicked static (e.g., sunbathing) humans (9.5%; n = 20 pairs). Thus, temporary beach closures that reduce or eliminate static but not mobile disturbances are likely to be effective at reducing disruption to incubation caused by human disturbance. © 2011 The Wildlife Society
Detection distance and environmental factors in conservation detection dog surveys
Authors: Reed Sarah E. , Bidlack Allison L. , Hurt Aimee , Getz Wayne M.
Published: March 2011

Surveys using conservation detection dogs have grown increasingly popular as an efficient means to gather monitoring data, particularly for elusive and low‐density species such as carnivores. Working with dogs can greatly increase the area surveyed for wildlife and the detection rate of survey targets. Due to the confounding effects of scent dispersion and dog movement, however, it can be difficult to estimate the area searched in a survey. Additionally, although detection dogs have been used in studies under a wide range of air temperature, humidity, and wind conditions, little research has examined how environmental factors affect detection dogs' effectiveness for wildlife surveys. Between 2003 and 2005, we trained 2 dogs to assist us with surveys for mammalian carnivore scats in northern California. We conducted controlled search trials to assess how the dogs' scat detection rates were affected by the distance of scats from the transect search line, as well as variation in six environmental factors. Both dogs detected >75% of scats located within 10 m, and the dogs' detection rates decreased with increasing distance of scats from the transect line. Among environmental factors, precipitation was the most important variable explaining variation in scat detection rates for both dogs. Precipitation likely degrades or removes scats from the landscape over time, and detection rates increase as scat begins to accumulate following the last substantial (>5 mm) rain event of the year. If scat accumulation is not controlled for in ecosystems with a strong seasonal pattern of rainfall, it could lead to considerable bias in study results. We recommend that researchers report the conditions under which conservation detection dog surveys took place and analyze how detection rates vary as a function of distance, temperature, precipitation, humidity, wind, and other locally important environmental factors. © 2010 The Wildlife Society.
Volume‐based trends in surgical care of patients with oropharyngeal cancer
Authors: Gourin Christine G. , Forastiere Arlene A. , Sanguineti Giuseppe , Marur Shanthi , Koch Wayne M. , Bristow Robert E.
Published: March 2011

Objective:

Positive volume–outcome relationships exist for diseases treated with technically complex surgery. Contemporary patterns of oropharyngeal cancer surgery by hospital and surgeon volume are poorly defined.

Methods:

The Maryland Health Service Cost Review Commission database was queried for hospital and surgeon oropharyngeal cancer surgical case volumes from 1990 to 2009.

Results:

Overall, 1,534 oropharyngeal cancer surgeries were performed by 238 surgeons at 41 hospitals. Cases performed by high‐volume surgeons increased from 18.9% in 1990 to 1999 to 24.8% in 2000 to 2009 (odds ratio [OR] = 1.5, P = .002), whereas cases performed at high‐volume hospitals increased from 35.0% to 41.8% (OR = 1.7, P <.001). High‐volume surgeons were significantly associated with university hospitals (OR = 25.9, P < .001) and were more likely to perform partial glossectomy (OR = 1.8, P = .002), total glossectomy (OR = 3.8, P < .001), and neck dissection (OR = 2.3, P < .001). High‐volume hospitals were significantly associated with tonsillectomy (OR = 3.0, P < .001), partial glossectomy (OR = 1.4, P = .044), total glossectomy (OR = 4.3, P < .001), neck dissection (OR = 3.1, P < .001), flap reconstruction (OR = 1.9, P = .028), and prior radiation (OR = 5.0, P < .001). After controlling for other variables, oropharyngeal cancer surgery in 2000 to 2009 was associated with increased utilization of university hospitals (OR = 1.7, P < .001), increased mortality risk scores (OR = 3.1, P = .022), prior radiation (OR = 4.9, P = .011), and a decrease in partial glossectomy (OR = 0.5, P < .001), total glossectomy (OR = 0.4, P = .004), pharyngectomy (OR = 0.6, P = .007), and mandibulectomy (OR = 0.6, P = .022) procedures.

Conclusions:

The proportion of oropharyngeal cancer surgery patients treated by high‐volume surgeons and hospitals increased significantly from 1990 to 1999 to 2000 to 2009, with a decrease in partial glossectomy, total glossectomy, pharyngectomy, and mandibulectomy procedures. These findings may be due to changing trends in the primary management of oropharyngeal cancer. Laryngoscope, 2011
Laser‐MSG‐Hybridschweißen von Schwarz‐Weiß‐Verbindungen
Authors: Jasnau Ulf , Sumpf André , Brandt René
Published: March 2011

Obwohl viele Industriezweige Schwarz‐Weiß‐Verbindungen einsetzen, liegen bislang nur wenige Erkenntnisse zum Schweißen solcher Materialkombinationen mit Hochleistungs‐Festkörperlasern vor. Das Projekt „Laserbasiertes Fügen von so genannten ‚SchwarzWeiß‐Verbindungen’︁ größerer Blechdicken mit dem Hochleistungsfaserlaser”︁ ermittelte Parameter, um das Metallschutz(MSG)‐Hybridschweißen mit Lasern auch für das Verbinden von Materialkombinationen aus unlegierten und hochlegierten Stählen größerer Blechdicken nutzbar zu machen. Dabei galt das besondere Interesse den geeigneten Nahtvorbereitungen und den Schweißparametern für das Schweißen von Stumpfnähten an Blechen und Rohren und Stumpfnähten am T‐Stoß.
Aus Tradition auf eigenen Wegen
Authors: Autz Irina , Friedrich Florian
Published: March 2011

Wie allgemein üblich, ändern sich beim Generationswechsel auch in einem Unternehmen der Blechbearbeitung neben den „Köpfen”︁ meist noch Strategien und Ziele. Dass dabei Lasermaschinen als Konstante bleiben, hat einen guten Grund: Sie erweisen sich gerade beim Bearbeiten von Blechen als Schlüssel für Neues.
Leadership begins with an inner journey
Authors: Kouzes James M. , Posner Barry Z.
Published: March 2011

Drawing on the stories of exemplary leaders, the authors argue that all effective leaders must make an inner journey “to discover who you are and what you care about.” Developing your ability to lead, they show, “is not about stuffing in a whole bunch of new information or trying out the latest technique. It's about leading out of what is already in your soul. It's about liberating the leader within you.”
Free‐radical polymerization: An international study
Authors: Eastmond G. C.
Published: March 2011

The International Union of Pure and Applied Chemistry established a Working Party to investigate selected aspects of the kinetics of free‐radical polymerization. This paper, which precedes formal reports of the Working Party's activities and experimental results, describes the experimental programme established. It highlights some aspects of the study and draws attention to lessons learned during the course of the programme.
Initiation of polymerization: Azo compounds and peroxides
Authors: Bevington John C.
Published: March 2011

Azobis(isobutyronitrile) and benzoyl peroxide are considered in detail as initiators of radical polymerization; the discussion is extended to other azo compounds and organic peroxides which can be used for the same purpose. Emphasis is placed on the value of isotopic labelling methods for study of the initiators and of the end–groups formed from them.
Initiation. The reactions of primary radicals
Authors: Solomon David H. , Moad Graeme
Published: March 2011

The various reactions undergone by primary radicals and the techniques employed in their study are described.
A review of the kinetics of the low conversion, free‐radical termination process
Authors: Mahabadi Hadi K.
Published: March 2011

A review of recent experimental and theoretical results exploring the free‐radical termination process in low conversion polymerization systems is presented. This very interesting and very specific, bimolecular termination step is vital in the development of free‐radical polymerization kinetics and is frequently assumed to operate independent of the reaction system. It is the authors' belief that a good deal of the scatter in low conversion kinetic parameter estimates prevalent in the current literature is due to the effect of nonideal free‐radical termination. While most current work is done in derivation of semi‐empirical correlations describing the magnitude of this effect, such methods lack generality since they, by design, ignore effects which are significant in describing the phenomena. Thus, the predictive ability of such models is compromised from the outset.

A general discussion of accepted low conversion kinetic modelling structures and applicable theoretical development of the process by which free‐radical termination occurs at low polymer concentrations is included. A review of current activities in this field is then presented, with a description of experimental techniques, pertinent results, a list of dominant effects and conclusions. Finally, a simple and comprehensive model structure is introduced which will be useful in analyzing low conversion kinetics and predicting rates and molecular weights from a variety of effects.

The intentions of this work are to order some of the more important results in the literature in the study of this particular reaction step and thus, provide some clarity and to demonstrate the sensitivity of this reaction step and its potential effect on kinetic predictions for free‐radical polymerizations.
Diffusion in dense polymer fluids
Authors: Lodge Timothy P. , Wheeler Louise , Hartley Brian , Huang W. James , Landry Michael R. , Frick Theodore S. , Lee Jeffrey A. , Tirrell Matthew
Published: March 2011

Most reactions involving a polymeric reactant are, or can easily become, diffusion‐controlled. While phenomenological models have been developed, direct fundamental knowledge of the diffusion, and data on the diffusion coefficients are lacking. Data on small molecule and polymer self‐diffusion coefficients are being obtained by two optical techniques over wide ranges of polymer concentration (0–100%) and diffusivity (10−14 to 10−5 cm2/sec). We present here a summary of our work of the last year in diffusion measurement by two different techniques. Forced Rayleigh Scattering (FRS) is being used to study small molecule diffusion in polymer fluids. Dynamic light scattering is being used to study polymer molecule diffusion over same range of variables. We hope through this work to be able to provide a complete picture of molecular mobility under polymerization conditions.
Non‐classical radical propagation
Authors: Kabanov Victor A.
Published: March 2011

Complexing of acrylic and methacrylic monomers with Lewis acids results both in their resonance stabilization and polarization of C=C bonds which cause a change of their reactivity in a classical sense. However, non‐classical reaction paths including growing radical‐monomer coordination in the transition state apparently play an important role in homo‐ and copolymerization of such monomers. An alternating copolymerization of acrylic and methacrylic monomers with olefines and dienes in the presence of Lewis acids in some cases proceeds due to a “classical” cross propagation rate constant increase. In the other cases alternation is caused by non‐classical mechanisms such as addition of comonomer complexes as the whole and (or) growing radical–monomer precomplexing. An alternating copolymerization of conventional donor‐acceptor monomer pairs also can proceed via classical and non‐classical reaction paths. ESR method combined with using of spin trap and corresponding kinetic measurements can be successfully applied for clarification of a propagation mechanism in each case.
Molecular weight distributions in free radical polymerizations
Authors: Rudin Alfred
Published: March 2011

In practical polymerization processes the goal is to control reaction conditions so as to produce polymers with optimum balances of properties for different applications. A key to success in this task is an understanding of the effects of the polymerization process on the molecular weight distribution (mwd) of the product as well as the response of polymer properties to changes in mwd. The effects of molecular weight and mwd on properties of commercial polymers made by free radical processes is dimly understood. Mechanical properties of polymer solids are theoretically related to mwd whereas the weight of the scanty evidence that is available suggests correlations with single average values, such as M̄n̄. By contrast, melt rheological properties are often referred to M̄w̄, while the evidence points to overriding effects of mwd.

Analyses of mwd's by gel permeation chromatography have made great advances recently, but the value of the results is limited by the relative insensitivity of the technique in the high and low molecular weight regions of the distribution. The differences between various grades of the same commodity polymer are apparently due to nuances in mwd in these regions.

Practical free radical polymerizations are very complex reactions. The reaction models must be correspondingly complex. Some illustrations of the value of experimental mwd data to guide predictions of kinetic schemes are given.
Structures and compositions of copolymers
Authors: Harwood H. James
Published: March 2011

Although studies on reactions of model radicals with olefins are becoming of increasing importance, most understanding of copolymerization has come from studies on copolymer composition and monomer unit sequence distribution information. A number of models for copolymerization have resulted from such studies. For most copolymerization systems the terminal model provides an adequate representation, but more complicated models which allow for the effects of penultimate units on radical reactivity, for reversibility of propagation steps and for participation of monomer complexes in copolymerization processes must be considered in some cases. Modeling of such copolymerization systems is considerably simplified by computer‐oriented approaches such as matrix–multiplication, Monte Carlo simulation and CSMP or ACSL programming. Recent studies on solvent effects in copolymerizations involving polar monomers indicate that partitioning of monomers between solvent and growing polymer radicals is a very significant phenomenon.
Determination of reactivity ratios in copolymerization
Authors: O'Driscoll K. F. , Reilly P. M.
Published: March 2011

Free radical copolymerization of two monomers is usually described in terms of reactivity ratios, only two of which are needed for the simplest (Mayo‐Lewis) model. Other, more complex models (such as penultimate unit effects or complex formation) require more kinetic parameters for a complete description. Published summaries of reactivity ratios list values for about 700 monomers taken from more than 1400 publications. These values represent an enormous amount of descriptive and physico‐chemical information about copolymerization in particular and free radical reactivity in general. It is important that we understand the limits to the numerical correctness of existing data, and that future data gathering be done in a statistically correct manner. In this paper several different linear and non‐linear regression approaches to estimating reactivity ratios are reviewed with emphasis being placed on the Mayo‐Lewis model. Two separate problems are recognized: the first is that of model discrimination, the second that of parameter estimation. It is rare that both problems can be properly treated with a single set of experiments, and we discuss the experimental approaches needed to obtain statistically good results.
Evaluation of alternative models for the mechanism of chain‐growth copolymerization
Authors: Hill David J.T. , O'Donnell James H.
Published: March 2011

A general method for discriminating between different models for chain‐growth copolymerization is described. The method is based on the non‐linear least‐squares analysis of variations in the copolymer compositions or sequence distributions with the compositions of the monomer feed mixture. It allows the best values for the reactivity ratios for each model to be evaluated, and their joint confidence regions to be delineated. The method is demonstrated by applications to the copolymerizations of styrene with acrylonitrile and maleic anhydride.
Recent investigations on the rate of binary and ternary copolymerizations
Authors: Braun D. , Czerwinski W. K.
Published: March 2011

In this paper a survey of the actual knowledge on the rate of binary and ternary copolymerizations is given. On the basis of various models of rate equations for binary copolymerizations the classical ternary rate equation of Melville et al. was further developed. New equations were derived for systems characterized by significant viscosity differences between the monomers and the viscosity control of termination is considered. Rate equations presented here were examined by measurements with two monomer systems: styrene/N‐vinyl pyrrolidone/ methylmethacrylate (system I) and diethylmaleate/methylmethacrylate/styrene (system II), both in bulk at 60° C with AIBN as initiator.
Rate of copolymerization in strongly alternating systems: The evidence for the involvement of monomer complexes
Authors: Ebdon John R.
Published: March 2011

Work on typical strongly alternating radical copolymerizations is reviewed. Emphasis is placed on measurements of rates of copolymerization as functions of monomer feed ratio, overall monomer concentration and solvent type. Particular attention is paid to the question of whether or not rate measurements can throw light on the detailed mechanisms of alternating radical copolymerizations and especially on whether or not they provide evidence for significant propagation via monomer‐monomer donor‐acceptor complexes. It is concluded that rate measurements alone are not necessarily a good guide to copolymerization mechanisms. A semi‐empirical method is proposed for assessing the likely reactivities of monomer‐monomer complexes; it is shown that this method predicts reactivities for monomer‐monomer complexes which are comparable with some calculated from rate and other data.
Heterogeneous radical polymerization: Reactivity and morphology control
Authors: Guyot A.
Published: March 2011

In the first part of that review, some physical effects are studied, causing changes in the kinetics and mechanism of polymerization reaction when going from an homogeneous solution polymerization to heterogeneous polymerizations. Three main cases are considered: acrylonitrile polymerization in which the polymer is neither soluble nor swollen by its monomer, vinyl chloride polymerization in which the polymer is not soluble in its monomer but is swollen by it, and styrene‐divinylbenzene resin where the apparent reactivity of the second double bond is governed by the syneresis phenomenon. In addition to the Tromsdorff effect on the termination reactions, perturbation due to the heterogeneous character of the reaction may affect the termination reaction by isolating free radicals, propagation reaction by restricting the mobility of the monomer or that of the growing radical through a template effect, or even transfer reactions on the polymer. Via concentration of pendent double bonds are observed inside crosslinked nodules of styrene‐divinylbenzene copolymers.

The second part is devoted to the study of morphology. Special emphasis is paid to the case of vinylchloride polymerization where the aggregation phenomena are governed by electrostatic interactions, and also to the case of styrene‐divinylbenzene resins where the formation of the morphology is discussed in terms of critical conversions for phenomena such as appearance of microgels, overlapping of nodules and phase separation. Similarities between porous morphology of PVC and styrene‐divinylbenzene resins are pointed out. Some discussions are also devoted to the supermolecular structures inside small particles in PVC, and also in multistep emulsion copolymerizations.