bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimisation of bronchial brachytherapy catheter placement with a modified airway stent
Authors: Kennedy M. P. , Jimenez C. A. , Chang J. , Fossella F. , Eapen G. A. , Morice R. C.
Published: March 2008

Brachytherapy is a modality of treatment available for lung cancer with tracheal involvement. Correct positioning of the brachytherapy catheter is vital to the optimisation of treatment effect and reduction of complications. Normal airway anatomy and tumour location can make this positioning difficult.

The current study presents the case of a 65-yr-old male with invasive tracheal squamous cell carcinoma of the anterior main carina involving the proximal left and right bronchus.

The patient was successfully treated with brachytherapy using a novel modified airway stent with a traversing suture for positioning and stabilising the brachytherapy catheters and maximisation of the radiation effect.

This simple yet innovative modification of readily available bronchoscopic equipment permits approximation and fixation of a brachytherapy catheter to any part of the proximal airway. Further analysis of this technique, including a prospective controlled trial, is planned.
Congenital anomalies and early functional impairments in a
prospective birth cohort: Risk of schizophrenia-spectrum disorder in
adulthood
Authors: Waddington John L. , Brown Alan S. , Lane Abbie , Schaefer Catherine A. , Goetz Raymond R. , Bresnahan Michaeline , Susser Ezra S.
Published: March 2008

Background

Adversities operating over intrauterine life have been associated with
risk of schizophrenia, but the biology of resultant developmental
perturbation is poorly understood.

Aims

To examine the relationship of congenital anomalies and related
functional impairments in infancy to risk of schizophrenia.

Method

Using the Congenital Anomalies data-set from the Prenatal Determinants of
Schizophrenia birth cohort, congenital anomalies and related functional
impairments were categorised and related to subsequent risk of
schizophrenia-spectrum disorder.

Results

The presence of any hypothesis-based congenital anomaly or related
functional impairment was associated with a doubling of risk of
schizophrenia-spectrum disorder. In contrast, having any other congenital
anomaly or related functional impairment was not associated with risk of
schizophrenia-spectrum disorder.

Conclusions

These findings constitute evidence for early events, which may result
from both genetic predisposition and environmental insults, in the
pathogenesis of schizophrenia.
A pilot personality disorder outreach service: development, findings and lessons learnt
Authors: Lee Tennyson , McLean Duncan , Moran Paul , Jones Hugh , Kumar Anil
Published: March 2008

Aims and Method

We describe the development of a pilot personality disorder outreach service. A case series of 13 patients was studied. Data were collected using pro forma, semi-structured interviews and a structured assessment of personality disorder.

Results

All personality disorder clusters were represented among the 13 patients. Treatment recommendations usually supported the existing approach – the ‘added value’ of the outreach service was that difficult interpersonal dynamics could be considered and thought through with an objective observer. Opinions differed on whether the service was more useful for the assessment and brief treatment or continuing care teams.

Clinical Implications

Personality disorder services need to develop expertise in all clusters. There is a need to moderate the harsh self-critical attitudes of the care coordinators. The national framework for personality disorder is useful for service development, but the services need to be tailored to the individual needs of specific teams.
Supplementary prescribing: a new way of working for psychiatrists and nurses
Authors: Harborne Giles , Jones Adrian
Published: March 2008

Aims and Method

To describe the implementation of supplementary prescribing and nurse-led care in an acute in-patient unit. The issues of delegation and distribution of responsibility were explicitly addressed. Structures were developed for training and supervision, to ensure improved medicines management in the acute setting.

Results

We present our five-step model of nurse-led in-patient care and our experience of using a clinical management plan for 33 patients.

Clinical Implications

Implementation of supplementary prescribing provides a model for new ways of working, requiring engagement of both doctors and nurses, clear delegation and distribution of responsibilities, and well-developed governance structures.
Methane as Fuel for Anaerobic Microorganisms
Authors: Thauer Rudolf K. , Shima Seigo
Published: March 2008

Methane has long been known to be used as a carbon and energy source by some aerobic alpha‐ and delta‐proteobacteria. In these organisms the metabolism of methane starts with its oxidation with O2 to methanol, a reaction catalyzed by a monooxygenase and therefore restricted to the aerobic world. Methane has recently been shown to also fuel the growth of anaerobic microorganisms. The oxidation of methane with sulfate and with nitrate have been reported, but the mechanisms of anaerobic methane oxidation still remains elusive. Sulfate‐dependent methane oxidation is catalyzed by methanotrophic archaea, which are related to the Methanosarcinales and which grow in close association with sulfate‐reducing delta‐proteobacteria. There is evidence that anaerobic methane oxidation with sulfate proceeds at least in part via reversed methanogenesis involving the nickel enzyme methyl‐coenzyme M reductase for methane activation, which under standard conditions is an endergonic reaction, and thus inherently slow. Methane oxidation coupled to denitrification is mediated by bacteria belonging to a novel phylum and does not involve methyl‐coenzyme M reductase. The first step in methane oxidation is most likely the exergonic formation of 2‐methylsuccinate from fumarate and methane catalyzed by a glycine‐radical enzyme.
Methanogenesis in Marine Sediments
Authors: Ferry James G. , Lessner Daniel J.
Published: March 2008

The anaerobic conversion of complex organic matter to CH4 is an essential link in the global carbon cycle. In freshwater anaerobic environments, the organic matter is decomposed to CH4 and CO2 by a microbial food chain that terminates with methanogens that produce methane primarily by reduction of the methyl group of acetate and also reduction of CO2. The process also occurs in marine environments, particularly those receiving large loads of organic matter, such as coastal sediments. The great majority of research on methanogens has focused on marine and freshwater CO2‐reducing species, and freshwater acetate‐utilizing species. Recent molecular, biochemical, bioinformatic, proteomic, and microarray analyses of the marine isolate Methanosarcina acetivorans has revealed that the pathway for acetate conversion to methane differs significantly from that in freshwater methanogens. Similar experimental approaches have also revealed striking contrasts with freshwater species for the pathway of CO‐dependent CO2 reduction to methane by M. acetivorans. The differences in both pathways reflect an adaptation by M. acetivorans to the marine environment.
Anaerobic Metabolism of Aromatic Compounds
Authors: Fuchs Georg
Published: March 2008

Aromatic compounds comprise a wide variety of natural and synthetic compounds that can serve as substrates for bacterial growth. So far, four types of aromatic metabolism are known. (1) The aerobic aromatic metabolism is characterized by the extensive use of molecular oxygen as cosubstrate for oxygenases that introduce hydroxyl groups and cleave the aromatic ring. (2) In the presence of oxygen, facultative aerobes use another so‐called hybrid type of aerobic metabolism of benzoate, phenylacetate, and anthranilate (2‐aminobenzoate). These pathways use coenzyme A thioesters of the substrates and do not require oxygen for ring cleavage; rather they use an oxygenase/reductase to dearomatize the ring. (3) In the absence of oxygen, facultative aerobes and phototrophs use a reductive aromatic metabolism. Reduction of the aromatic ring of benzoyl‐coenzyme A is catalyzed by benzoyl‐coenzyme A reductase. This Birch‐like reduction is driven by the hydrolysis of 2 ATP molecules. (4) A completely different, still little characterized benzoyl‐coenzyme A reductase operates in strict anaerobes, which cannot afford the costly ATP‐dependent ring reduction.
Hydrogenases of the Model Hyperthermophiles
Authors: Jenney Francis E. , Adams Michael W. W.
Published: March 2008

Hydrogenases are enzymes found in all domains of life that catalyze a remarkably simple chemistry, the reversible oxidation of molecular hydrogen to protons and electrons. In order to perform this chemistry, cells have evolved, several different times, intricate organometal complexes built around a binuclear Ni‐Fe or Fe‐Fe center, with bound CO and CN− groups, as well as multiple FeS centers. These complicated enzymes have been an area of intense study for many decades, with interest peaking on the occasions of major increases in national energy costs. Interest in biologically generated hydrogen as a potential substitute for fossil fuels is again at the forefront, and the new tools of the postgenomic world available for manipulating these enzymes make it a truly viable possibility. Hydrogenases from hyperthermophilic microorganisms such as Pyrococcus furiosus and Thermotoga maritima, with optimal growth temperatures near 100°C, are of particular interest and promise for elucidating and manipulating these enzymatic mechanisms.
Old Acetogens, New Light
Authors: Drake Harold L. , Gößner Anita S. , Daniel Steven L.
Published: March 2008

Acetogens utilize the acetyl‐CoA Wood‐Ljungdahl pathway as a terminal electron‐accepting, energy‐conserving, CO2‐fixing process. The decades of research to resolve the enzymology of this pathway (1) preceded studies demonstrating that acetogens not only harbor a novel CO2‐fixing pathway, but are also ecologically important, and (2) overshadowed the novel microbiological discoveries of acetogens and acetogenesis. The first acetogen to be isolated, Clostridium aceticum, was reported by Klaas Tammo Wieringa in 1936, but was subsequently lost. The second acetogen to be isolated, Clostridium thermoaceticum, was isolated by Francis Ephraim Fontaine and co‐workers in 1942. C. thermoaceticum became the most extensively studied acetogen and was used to resolve the enzymology of the acetyl‐CoA pathway in the laboratories of Harland Goff Wood and Lars Gerhard Ljungdahl. Although acetogenesis initially intrigued few scientists, this novel process fostered several scientific milestones, including the first 14C‐tracer studies in biology and the discovery that tungsten is a biologically active metal. The acetyl‐CoA pathway is now recognized as a fundamental component of the global carbon cycle and essential to the metabolic potentials of many different prokaryotes. The acetyl‐CoA pathway and variants thereof appear to be important to primary production in certain habitats and may have been the first autotrophic process on earth and important to the evolution of life. The purpose of this article is to (1) pay tribute to those who discovered acetogens and acetogenesis, and to those who resolved the acetyl‐CoA pathway, and (2) highlight the ecology and physiology of acetogens within the framework of their scientific roots.
Three Microbial Strategies for Plant Cell Wall Degradation
Authors: Wilson David B.
Published: March 2008

Cellulolytic bacteria and fungi have been shown to use two different approaches to degrade cellulose. Most aerobic microbes secrete sets of individual cellulases, many of which contain a carbohydrate binding molecule (CBM), which act synergistically on native cellulose. Most anaerobic microorganisms produce large multienzyme complexes called cellulosomes, which are usually attached to the outer surface of the microorganism. Most of the cellulosomal enzymes lack a CBM, but the cohesin subunit, to which they are bound, does contain a CBM. The cellulases present in each class show considerable overlap in their catalytic domains, and processive cellulases (exocellulases and processive endocellulases) are the most abundant components of both the sets of free enzymes and of the cellulosomal cellulases. Analysis of the genomic sequences of two cellulolytic bacteria, Cytophaga hutchinsonii, an aerobe, and Fibrobacter succinogenes, an anaerobe, suggest that these organisms must use a third mechanism. This is because neither of these organisms, encodes processive cellulases and most of their many endocellulase genes do not encode CBMs. Furthermore, neither organism appears to encode the dockerin and cohesin domains that are key components of cellulosomes.
Diversity of Thermophilic Anaerobes
Authors: Wagner Isaac D. , Wiegel Juergen
Published: March 2008

Thermophilic anaerobes are Archaea and Bacteria that grow optimally at temperatures of 50°C or higher and do not require the use of O2 as a terminal electron acceptor for growth. The prokaryotes with this type of physiology are studied for a variety of reasons, including (a) to understand how life can thrive under extreme conditions, (b) for their biotechnological potential, and (c) because anaerobic thermophiles are thought to share characteristics with the early evolutionary life forms on Earth. Over 300 species of thermophilic anaerobes have been described; most have been isolated from thermal environments, but some are from mesobiotic environments, and others are from environments with temperatures below 0°C. In this overview, the authors outline the phylogenetic and physiological diversity of thermophilic anaerobes as currently known. The purpose of this overview is to convey the incredible diversity and breadth of metabolism within this subset of anaerobic microorganisms.
The anatomically difficult primary total hip replacement
Authors: Biant L. C. , Bruce W. J. M. , Assini J. B. , Walker P. M. , Walsh W. R.
Published: March 2008

This prospective study presents the ten-year (5 to 16) clinical and radiological results of 55 primary total hip replacements (THR) using a cementless modular femoral component (S-ROM). All patients had a significant anatomical abnormality which rendered the primary THR difficult.

The mean Harris hip score was 36 (12 to 72) pre-operatively, 83 (44 to 100) at five years, and 85 (45 to 99) at ten years. The Western Ontario and McMaster Universities osteoarthritis index (WOMAC) and short-form (SF)-12 scores were recorded from the year 2000. The mean SF-12 score at five years after surgery was 45.24 (22.74 to 56.58) for the physical component and 54.14 (29.20 to 66.61) for the mental component. By ten years the SF-12 scores were 42.86 (21.59 to 58.95) and 51.03 (33.78 to 61.40), respectively. The mean WOMAC score at five years post-operatively was 25 (0 to 59), and at ten years was 27 (2 to 70).

No femoral components were radiologically loose, although five had osteolysis in Gruen zone 1, three had osteolysis in zone 7, and two showed osteolysis in both zones 1 and 7. No osteolysis was observed around or distal to the prosthetic sleeve. No femoral components were revised, although three hips underwent an acetabular revision and two required a liner exchange. At a mean of ten years’ follow-up the S-ROM femoral component implanted for an anatomically difficult primary THR has excellent clinical and radiological results.
Differences in length and cross-section of semitendinosus and gracilis tendons and their effect on anterior cruciate ligament reconstruction
Authors: Pichler W. , Tesch N. P. , Schwantzer G. , Fronhöfer G. , Boldin C. , Hausleitner L. , Grechenig W.
Published: March 2008

The purpose of this anatomical study was to explore the morphological variations of the semitendinosus and gracilis tendons in length and cross-section and the statistical relationship between length, cross-section, and body height.

We studied the legs of 93 humans in 136 cadavers. In 43 specimens (46.2%) it was possible to harvest the tendons from both legs.

We found considerable differences in the length and cross-section of the semitendinosus and the gracilis tendons with a significant correlation between the two. A correlation between the length of the femur, reflecting height, and the length of the tendons was only observed in specimens harvested from women. The reason for this gender difference was unclear. Additionally, there was a correlation between the cross-sectional area of the tendons and the length of the femur. Surgeons should be aware of the possibility of encountering insufficient length of tendon when undertaking reconstructive surgery as a result of anatomical variations between patients.
The results of two-stage re-implantation for infected shoulder replacement
Authors: Strickland J. P. , Sperling J. W. , Cofield R. H.
Published: March 2008

While frequently discussed as a standard treatment for the management of an infected shoulder replacement, there is little information on the outcome of two-stage re-implantation.

We examined the outcome of 17 consecutive patients (19 shoulders) who were treated between 1995 and 2004 with a two-stage re-implantation for the treatment of a deep-infection after shoulder replacement. All 19 shoulders were followed for a minimum of two years or until the time of further revision surgery. The mean clinical follow-up was for 35 months (24 to 80). The mean radiological follow-up was 27 months (7 to 80). There were two excellent results, four satisfactory and 13 unsatisfactory. In 12 of the 19 shoulders (63%) infection was considered to be eradicated. The mean pain score improved from 4.2 (3 to 5 (out of 5)) to 1.8 (1 to 4). The mean elevation improved from 42° (0° to 140°) to 89° (0° to 165°), mean external rotation from 30° (0° to 90°) to 43° (0° to 90°), and mean internal rotation from the sacrum to L5. There were 14 complications.

Our study suggests that two-stage re-implantation for an infected shoulder replacement is associated with a high rate of unsatisfactory results, marginal success at eradicating infection and a high complication rate.
MRI surveillance after resection for primary musculoskeletal sarcoma
Authors: Watts A. C. , Teoh K. , Evans T. , Beggs I. , Robb J. , Porter D.
Published: March 2008

This study reports the experience of one treatment centre with routine surveillance MRI following excision of musculoskeletal sarcoma. The case notes, MRI and histology reports for 57 patients were reviewed. The primary outcome was local tumour recurrence detected on either surveillance MRI in asymptomatic patients, or interval MRI in patients with clinical concern. A total of 47 patients had a diagnosis of soft-tissue sarcoma and ten of a primary bone tumour. A total of 13 patients (22%) had local recurrence. Nine were identified on a surveillance scan, and four by interval scans. The cost of surveillance is estimated to be £4414 per recurrence detected if low-grade tumours with clear resection margins are excluded. Surveillance scanning has a role in the early detection of local recurrence of bone and soft-tissue sarcoma.
Refracture after Ilizarov osteosynthesis in atrophic-type congenital pseudarthrosis of the tibia
Authors: Cho T.-J. , Choi I. H. , Lee S. M. , Chung C. Y. , Yoo W. J. , Lee D. Y. , Lee J. W.
Published: March 2008

We investigated patterns of refracture and their risk factors in patients with congenital pseudarthrosis of the tibia after Ilizarov osteosynthesis. We studied 43 cases in 23 patients. Temporal and spatial patterns of refracture and refracture-free survival were analysed in each case. The refracture-free rate of cumulative survival was 47% at five years and did not change thereafter. Refracture occurred at the previous pseudarthrosis in 16 of 19 cases of refracture. The risk of refracture was significantly higher when osteosynthesis was performed below the age of four years, when the tibial cross-sectional area was narrow, and when associated with persistent fibular pseudarthrosis. Refracture occurs frequently after successful osteosynthesis in these patients. Delaying osteosynthesis, maximising the tibial cross-sectional area and stabilising the fibula may reduce the risk of refracture.
Focal femoral osteolysis after revision hip replacement with a cannulated, hydroxyapatite-coated long-stemmed femoral component
Authors: Rose D. M. , Guryel E. , Acton K. J. , Clark D. W.
Published: March 2008

We describe a case of symptomatic focal femoral osteolysis around a screw hole distal to the hydroxyapatite-coated portion of a cannulated femoral component in a revision hip replacement. No locking screw had been inserted into this, the most proximal of the three distal holes for locking screws. The presence of polyethylene wear debris in the tissue excised from the lesion suggested that it had passed through the cannulated portion of the stem and out of the proximal unfilled distal locking hole, initiating an osteolytic reaction in an otherwise well-fixed stem. This case highlights an important design characteristic of such cannulated, uncemented femoral components. We recommend that the proximal aperture of these cannulated stems be occluded at implantation.
Gender differences in epidemiology and outcome after hip fracture
Authors: Holt G. , Smith R. , Duncan K. , Hutchison J. D. , Gregori A.
Published: March 2008

We report gender differences in the epidemiology and outcome after hip fracture from the Scottish Hip Fracture Audit, with data on admission and at 120 days follow-up from 22 orthopaedic units across the country between 1998 and 2005. Outcome measures included early mortality, length of hospital stay, 120-day residence and mobility. A multivariate logistic regression model compared outcomes between genders. The study comprised 25 649 patients of whom 5674 (22%) were men and 19 975 (78%) were women. The men were in poorer pre-operative health, despite being younger at presentation (mean 77 years (60 to 101) vs 81 years (50 to 106)). Pre-fracture residence and mobility were similar between genders.

Multivariate analysis indicated that the men were less likely to return to their home or mobilise independently at the 120-day follow-up. Mortality at 30 and 120 days was higher for men, even after differences in case-mix variables between genders were considered.
The assessment of early osteoarthritis
Authors: Pollard T. C. B. , Gwilym S. E. , Carr A. J.
Published: March 2008

Treatment strategies for osteoarthritis most commonly involve the removal or replacement of damaged joint tissue. Relatively few treatments attempt to arrest, slow down or reverse the disease process. Such options include peri-articular osteotomy around the hip or knee, and treatment of femoro-acetabular impingement, where early intervention may potentially alter the natural history of the disease. A relatively small proportion of patients with osteoarthritis have a clear predisposing factor that is both suitable for modification and who present early enough for intervention to be deemed worthwhile. This paper reviews recent advances in our understanding of the pathology, imaging and progression of early osteoarthritis.
Obesity in total hip replacement
Authors: Andrew J. G. , Palan J. , Kurup H. V. , Gibson P. , Murray D. W. , Beard D. J.
Published: March 2008

A prospective, multi-centre study was carried out on 1421 total hip replacements between January 1999 and July 2007 to examine if obesity has an effect on clinical outcomes.

The patients were categorised into three groups: non-obese (body mass index (BMI) < 30 kg/m2), obese (BMI 30 to 40 kg/m2) and morbidly obese (BMI > 40 kg/m2). The primary outcome measure was the change in Oxford hip score at five years. Secondary outcome measures included dislocation and revision rates, increased haemorrhage, deep infection, deep-vein thrombosis and pulmonary embolism, mean operating time and length of hospital stay. Radiological analysis assessing heterotopic ossification, femoral osteolysis and femoral stem positioning was performed. Data were incomplete for 362 hips (25.5%)

There was no difference in the change in the Oxford hip score, complication rates or radiological changes at five years between the groups. The morbidly obese group was significantly younger and required a significantly longer operating time. Obese and morbidly obese patients have as much to gain from total hip replacement as non-obese patients.
Rotatorischer MRF-Aktor für einen Türassistenten (Rotary MRF-Actuator for an Automotive Door Assistent)
Authors: Wiehe Ansgar , Kern Simon , Maas Jürgen
Published: March 2008

Aktoren auf Basis magnetorheologischer Fluide zeichnen sich durch eine hochdynamische und weitgehend lineare Verstellung der Schubspannung aus und stellen deshalb eine interessante Alternative zu konventionellen Bremsen, Kupplungen und Dämpfern dar. Im Rahmen dieses Beitrags wird ein rotatorischer MRF-Aktor modellgestützt entworfen, der sich insbesondere für die Bewegungssteuerung von Türen und Klappen in Fahrzeugen eignet.

Actuators based on magnetorheological fluids offer a high dynamical and almost linear force generation and represent therefore an interesting alternative for conventional brakes, clutches und dampers. In this paper a model-based design of a rotary MRF-actuator is described. The designed actuator is especially suited for the motion control of automotive doors.
Ionization-induced effects in amorphous apatite at elevated temperatures
Authors: Bae In-Tae , Zhang Yanwen , Weber William J. , Ishimaru Manabu , Hirotsu Yoshihiko , Higuchi Mikio
Published: March 2008

Electron-beam-induced effects in preamorphized Sr2Nd8(SiO4)6O2 were investigated in situ using transmission electron microscopy with 200-keV electrons at temperatures ranging from 380 to 780 K. Within the electron-irradiated area, epitaxial recrystallization was observed from the amorphous/crystalline interface toward the surface, with the rate of recrystallization increasing as temperature increased from 380 to 580 K. Structural contrast features (i.e., O deficient amorphous material), as well as recrystallization, were observed outside of the irradiation area at temperatures from 680 to 780 K. Ionization-induced processes and local nonstoichiometry induced by oxygen migration and desorption are possible mechanisms for the electron-beam- induced recrystallization and for the formation of the structural contrast features, respectively.
Synthesis, microstructure and hardness of bulk ultrahard BN nanocomposites
Authors: Rafaja D. , Klemm V. , Motylenko M. , Schwarz M.R. , Barsukova T. , Kroke E. , Frost D. , Dubrovinsky L. , Dubrovinskaia N.
Published: March 2008

Ultrahard boron nitride compacts containing nanosized domains of the cubic (c-BN), wurtzitic (w-BN), and hexagonal (h-BN) phase were synthesized at high-pressure/high-temperature (HP/HT) conditions. Hot-pressed and pyrolytic BN, both containing h-BN as a main component, were used as starting materials. The HP/HT products were investigated by x-ray diffraction via Rietveld and line-profile analysis, as well as high-resolution transmission electron microscopy. c-BN was the dominant phase in all products, complemented by up to 25 wt% w-BN and some remaining “compressed h-BN.” In particular samples, partial crystallographic coherence of adjacent crystallites to x-rays was observed, which has been previously found in superhard transition metal nitride-based nanocomposite coatings. In the BN nanocomposites, the partial coherence of nanocrystallites to x-rays was improved by their strong local preferred orientation, which is made possible by the well-known orientation relationships among h-BN, w-BN, and c-BN phases. The correlation between the weight fraction and the average size of the c-BN crystallites helped to describe the formation of c-BN/(w-BN) nanocomposites from submicron-sized h-BN domains in the starting materials. The Knoop and Vickers hardness of specimens with crystallite sizes ranging from 6 to ∼50 nm was found to be significantly higher than that of c-BN single crystals, despite the presence of residual h-BN.
Microscopic investigation of modified hydration kinetics in tricalcium silicate paste and mortar strength caused by dicalcium silicate addition
Authors: Peterson Vanessa K. , Stutzman Paul E. , Livingston Richard A.
Published: March 2008

It was recently revealed that some processes of hydrating tricalcium silicate are altered by the addition of dicalcium silicate. Previous neutron scattering results revealed two critical tri/dicalcium silicate compositions. At one composition, changes in the early time hydration kinetics were observed that result in the formation of more products (reflected in increased 28 day strength), despite dicalcium silicate being essentially unreactive at early times. At the other composition, changes in the early-time hydration kinetics were observed that correspond to reduced strength. The current work uses scanning electron microscope analysis with backscattered electron imaging of 50 day hydrated tri- and dicalcium silicate mortars to reveal that at the former critical composition increased hydration of the tricalcium silicate phase occurs, and at the latter critical composition, the amount of dicalcium silicate reacted is decreased.
Experimental method to account for structural compliance in nanoindentation measurements
Authors: Jakes J.E. , Frihart C.R. , Beecher J.F. , Moon R.J. , Stone D.S.
Published: March 2008

The standard Oliver–Pharr nanoindentation analysis tacitly assumes that the specimen is structurally rigid and that it is both semi-infinite and homogeneous. Many specimens violate these assumptions. We show that when the specimen flexes or possesses heterogeneities, such as free edges or interfaces between regions of different properties, artifacts arise in the standard analysis that affect the measurement of hardness and modulus. The origin of these artifacts is a structural compliance (Cs), which adds to the machine compliance (Cm), but unlike the latter, Cs can vary as a function of position within the specimen. We have developed an experimental approach to isolate and remove Cs. The utility of the method is demonstrated using specimens including (i) a silicon beam, which flexes because it is supported only at the ends, (ii) sites near the free edge of a fused silica calibration standard, (iii) the tracheid walls in unembedded loblolly pine (Pinus taeda), and (iv) the polypropylene matrix in a polypropylene–wood composite.
Polarity effect of electromigration on intermetallic compound formation in a Cu/Sn–9Zn/Cu sandwich
Authors: Kuo Shih-Ming , Lin Kwang-Lung
Published: March 2008

This study investigated the polarity effect of electromigration (EM) on the interfacial intermetallic compounds (IMCs) (γ-Cu5Zn8, Cu6Sn5) formation at the anode and the cathode in a Cu/Sn-9Zn/Cu sandwich with a constant direct current density of 1.0 × 103 A/cm2 at 100 °C. The EM had different polarity effects on the nucleation and growth rates of the interfacial Cu5Zn8 IMC from those of Cu6Sn5 IMC. Upon current stressing, the growth rate of the Cu-Zn intermetallic compound (γ-Cu5Zn8) at the cathode interface was much faster than that at the anode. However, the nucleation and growth of the Cu6Sn5 IMC at the anode interface were enhanced, though retarded at the cathode, under the influence of electric current. The mechanism of EM-induced Cu6Sn5 IMC formation towards the anodic Cu is also discussed.
Solvothermal approach to nanocrystalline Li–Ti–O insertion hosts–solvent polarity effect
Authors: Kostlánová Tereza , Makarova Marina V. , Krtil Petr
Published: March 2008

The cubic nanocrystalline Li–Ti–O oxides were prepared by the solvothermal reaction of TiO2 and LiOH at 200 °C in water and aliphatic alcohols with different dielectric constants. The reaction in all solvents leads to the formation of white ternary compounds containing Li, Ti, and O. The actual Li content in the prepared materials increases with decreasing polarity of the used solvent. All prepared materials are crystalline, and their structure can be described using a spinel structural model. The structure of materials prepared at a relative dielectric constant (ϵr) value higher than 33 is characterized by Ti disorder when the Ti atoms are distributed between both types of the available octahedral sites with approximately the same probability. The tendency to form phases with Ti disorder decreases with decreasing ϵr of the solvent. All prepared materials are active toward electrochemical Li insertion. The observed specific capacity ranges between 60 and 150 mAh/g.
Contact fatigue of silicon
Authors: Bhowmick Sanjit , Meléndez-Martínez Juan José , Lawn Brian R.
Published: March 2008

Macroscopic cracks in bulk silicon are generally considered to be immune to fatigue. Here, evidence for pronounced fracture-related fatigue damage in cyclic contact loading of (001) monocrystalline silicon with hard spheres of millimeter-scale radius is presented. The periodic indentation field generates ring cracks around the contact, which proliferate with continued cycling. Copious debris in the form of slabs and particulates is ejected from within the crack walls onto the specimen surface. Continued ejection leads ultimately to large-scale surface removal. The fatigue damage progressively degrades the material strength, more rapidly at higher contact load. Implications concerning the function of silicon devices, including microelectro-mechanical systems, will be briefly discussed.
Genetic Assessment of Lake Sturgeon Population Structure in the Laurentian Great Lakes
Authors: Welsh Amy , Hill Tracy , Quinlan Henry , Robinson Charmaine , May Bernie
Published: March 2008

Many populations of lake sturgeon Acipenser fulvescens have decreased in size throughout the Great Lakes basin. To implement management strategies such as stocking, it is important to understand the genetic structure of lake sturgeon spawning populations. Lake sturgeon from 27 spawning locations (25 from the Great Lakes basin and 2 from the Hudson Bay drainage) were analyzed using 12 microsatellite loci. Population structure was detected at different spatial scales. At the largest scale, consistent genetic breaks were observed among three clusters of spawning populations: (1) Hudson Bay–northern Lake Superior, (2) southern Lake Superior, and (3) the rest of the Great Lakes. These clusters were identified using a Bayesian approach that does not define the populations a priori. Within each of the three clusters, sublevels of genetic structure were detected. These sublevel clusters accounted for 8.82% of the genetic variation (P < 0.000), while differences among populations within the clusters accounted for 3.72% of the genetic variation (P < 0.000). At the smallest scale, significant genetic differentiation was detected between most sampled locations through pairwise genetic differentiation index (FST) tests and pairwise contingency tests. Lake sturgeon showed greater genetic differentiation in Lake Superior than elsewhere, which could be due to the lake's bathymetry. The lower genetic resolution observed elsewhere in the Great Lakes could be due to more recent colonization events. The results can be used to delineate management units and to select appropriate donor populations for supplementation or reintroductions.
Forecasting Walleye Abundance in Northern Wisconsin Lakes
Authors: Madsen Eric R.
Published: March 2008

Seventeen variations of a modified statistical catch-at-age model were applied to annual spawning adult mark–recapture population estimates (PEs) for walleye Sander vitreus from seven mixed-fishery lakes in northern Wisconsin. In addition, 15 variations were applied to annual PEs for walleyes age 3 and older from Escanaba Lake. The model variations included different mortality, selectivity, and catchability assumptions, as well as different data weightings, averaging of forecasts, and naïve models using limited data. Population forecasts were examined retrospectively for each model variation to evaluate whether they were accurate enough to use as a basis for setting harvest quotas. Models were ranked according to how closely the forecasts matched the PEs and the abundance estimates fitted using all available data. A model that used estimated mortality and averaging of forecasts performed best for the large mixed-fishery lakes, and a model that used fixed mortality and downweighted age composition data performed best for the small mixed-fishery lakes. These model forecasts can be considered for setting harvest quotas on the mixed-fishery lakes since they performed better than the naïve models, but the improvements were modest. For the large mixed-fishery lakes, the mean absolute deviation and mean deviation of the forecasts from the PEs were 38% and 13%, respectively, for the naïve model using the previous year's PE as the forecast and 31% and 3%, respectively, for the best model; for the small mixed-fishery lakes, these deviations were 34% and 16%, respectively, for this naïve model and 36% and 12%, respectively, for the best model. A naïve model using the previous year's fitted abundance as the forecast performed best for Escanaba Lake. Model forecasts performed poorly for Escanaba Lake, mostly because of the age composition of the population being estimated.
Factors Affecting Catch-and-Release Mortality of Bluefish
Authors: Fabrizio Mary C. , Scharf Frederick S. , Shepherd Gary R. , Rosendale John E.
Published: March 2008

Recreational harvests of bluefish Pomatomus saltatrix along the U.S. coast from Maine to Florida exceed commercial harvests, and in recent years about 60–70% of angler-captured fish are released alive. The proportion of fish that survive hooking, handling, and release back to the ocean is unknown; however, if catch-and-release mortality is high, it may represent a significant component of the overall bluefish mortality rate. We estimated long-term (21-d) hooking mortality rates of field-captured bluefish and investigated the effects of various factors on postrelease mortality. Age, length, and the occurrence of bleeding were significant factors associated with catch-and-release mortality, which we estimated to be 38.8%. About 65% of the mortality was initial mortality, and the remainder was delayed mortality. We also performed a laboratory study to examine the physiological response of bluefish to two independent processes (hooking and release versus transfer in coolers to the laboratory) relevant to the field study. Laboratory-held fish that were hooked and released exhibited elevated concentrations of potassium in their blood, suggesting that they experienced either an osmotic imbalance or cellular damage. Laboratory-held fish exposed to the transfer treatment only exhibited osmotic imbalance (elevated plasma sodium concentration) and evidence of anaerobic metabolism (elevated plasma lactate concentration). Our findings indicate that bluefish age and size contribute to variable levels of metabolic stress and that delayed postrelease mortality is considerable.
Genetic Assessment of Sheepshead Stock Structure in the Northern Gulf of Mexico: Morphological Divergence in the Face of Gene Flow
Authors: Anderson Joel D. , Karel William J. , Anderson Kathryn A. , Roper-Foo Pilar A.
Published: March 2008

Strategies for conservation and management of marine species are increasingly relying on molecular genetic data for the delineation of independent fishery stocks. These data may be more reliable and less subjective than morphological or ecological variables, although their biological interpretations can be problematic. Here, we review existing morphological data synergistically with a new molecular data set for sheepsheads Archosargus probatocephalus. Two named subspecies of sheepshead exist in the northeastern Gulf of Mexico (A. probatocephalus probatocephalus and A. probatocephalus oviceps). Although these subspecies exhibit divergent morphology, it is unclear whether morphological divergence represents meaningful differentiation for management. We show that frequency distributions of each of five meristic counts are significantly different between the subspecies (P < 0.05). However, Bayesian structure analysis of microsatellite genotypes indicated that all Gulf of Mexico sheepshead populations constitute a single stock (posterior probability ≈ 0.9999). Variance partitioning of mitochondrial DNA (mtDNA) haplotypes suggests significant but limited divergence between subspecies (genetic differentiation index FST = 0.036, P < 0.005). Patterns of pairwise mtDNA genetic distance and microsatellite divergence suggest that isolation by distance, rather than subdivision among independent genetic stocks, is driving the significance of variance analyses. Overall, sheepshead molecular genetic data indicate very limited genetic subdivision between the subspecies despite considerable divergence of morphological characters. These results have multiple interpretations, each of which carries implications for the management of this species in the Gulf of Mexico.
Estimating Stock Composition of Anadromous Fishes from Mark–Recovery Data: Possible Application to American Shad
Authors: Hoenig John M. , Latour Robert J. , Olney John E.
Published: March 2008

Information on the stock composition of mixed-stock fisheries is often needed to develop management regulations for anadromous fishes. Although several methods can be used to infer stock composition, marking studies have long been identified as a promising approach. Hatchery-reared larval American shad Alosa sapidissima are marked with a river-specific mark and released in stock enhancement programs along the U.S. East Coast. We describe and apply a mark–recovery method for inferring the proportion of the catch in a mixed-stock fishery that originates from a particular river. The method is based on comparing the proportion of the mixed-stock catch with marks from the river with the proportion of the fish returning to the river with marks. We explore the utility of using mass marking of hatchery-reared American shad larvae with tetracycline to determine the stock composition of mixed-stock fisheries of American shad in Virginia. Our analysis focuses on the impact of the former Virginia coastal ocean fishery on fish produced in the James and Pamunkey rivers, Virginia, and on the impact of bycatch in Chesapeake Bay pound nets on Susquehanna River American shad. Our results suggest that the coastal ocean fishery harvested relatively small proportions of the James and Pamunkey River stocks and that few American shad captured in pound nets sampled in Chesapeake Bay were from the Susquehanna River system.
Commentary: Novel Therapies for Cancer: Why Dirty Might Be Better
Authors: Fojo Tito
Published: March 2008

In the era of targeted therapy, many have argued that targeted therapies would not only be more effective but also less toxic. However, the early evidence suggests that the assumption that greater specificity would result in greater efficacy may have been premature. In fact, it can be argued that dirty may be better than clean.
CONTINGENCY TRACKING DURING UNSIGNALED DELAYED REINFORCEMENT
Authors: Keely Josue , Feola Tyler , Lattal Kennon A.
Published: March 2008

Three experiments were conducted with rats in which responses on one lever (labeled the functional lever) produced reinforcers after an unsignaled delay period that reset with each response during the delay. Responses on a second, nonfunctional, lever did not initiate delays, but, in the first and third experiments, such responses during the last 10 s of a delay did postpone food delivery another 10 s. In the first experiment, the location of the two levers was reversed several times. Responding generally was higher on the functional lever, though the magnitude of the difference diminished with successive reversals. In the second experiment, once a delay was initiated by a response on the functional lever, in different conditions responses on the nonfunctional lever either had no effect or postponed food delivery by 30 s. The latter contingency typically lowered response rates on the nonfunctional lever. In the first two experiments, both the functional and nonfunctional levers were identical except for their location; in the third experiment, initially, a vertically mounted, pole‐push lever defined the functional response and a horizontally mounted lever defined the nonfunctional response. Higher response rates occurred on the functional lever. These results taken together suggest that responding generally tracked the response‐reinforcer contingency. The results further show how nonfunctional‐operanda responses are controlled by a prior history of direct reinforcement of such responses, by the temporal delay between such responses and food delivery, and as simple generalization between the two operanda.
TRANSFORMATION OF THE DISCRIMINATIVE AND ELICITING FUNCTIONS OF GENERALIZED RELATIONAL STIMULI
Authors: Dougher Michael J. , Hamilton Derek A. , Fink Brandi C. , Harrington Jennifer
Published: March 2008

In three experiments, match‐to‐sample procedures were used with undergraduates to establish arbitrary relational functions for three abstract visual stimuli. In the presence of samples A, B, and C, participants were trained to select the smallest, middle, and largest member, respectively, of a series of three‐comparison arrays. In Experiment 1, the B (choose middle) stimulus was then used to train a steady rate of keyboard pressing before the A (choose smallest) and the C (choose largest) stimuli were presented. Participants pressed slower to A and faster to C than to B. Then B was paired with mild shock in a Pavlovian procedure with skin conductance change as the dependent variable. When presented with A and C, 6 of 8 experimental participants showed smaller skin conductance changes to A and larger skin conductance changes to C than to B. In Experiment 2, A was then used as a sample in a match‐to‐sample procedure to establish an arbitrary size ranking among four same‐sized colored circle comparisons. One of the middle circles was then used to establish a steady rate of pressing before the other circles were presented. Five of 6 participants responded slower to the “smaller” circle and faster to the “larger” circle than they did to the “middle” circle. In Experiment 3, A, B, and C were then presented on a series of test trials requiring participants to pick the comparison that was less than, greater than, or equal to the sample. Novel stimuli were included on some trials. Results indicated that the relational training procedures produced derived relations among the stimuli used in training and that these allowed correct inferences of relative size ranking among novel stimuli.