bluuebunny/crossref_metadata_2025 huggingface dataset:
Plant Community Structure in Tropical Rain Forest Fragments of the Western Ghats, India1
Authors: Muthuramkumar S. , Ayyappan N. , Parthasarathy N. , Mudappa Divya , Raman T. R. Shankar , Selwyn M. Arthur , Pragasan L. Arul
Published: December 2005

Changes in tree, liana, and understory plant diversity and community composition in five tropical rain forest fragments varying in area (18–2600 ha) and disturbance levels were studied on the Valparai plateau, Western Ghats. Systematic sampling using small quadrats (totaling 4 ha for trees and lianas, 0.16 ha for understory plants) enumerated 312 species in 103 families: 1968 trees (144 species), 2250 lianas (60 species), and 6123 understory plants (108 species). Tree species density, stem density, and basal area were higher in the three larger (> 100 ha) rain forest fragments but were negatively correlated with disturbance scores rather than area per se. Liana species density, stem density, and basal area were higher in moderately disturbed and lower in heavily disturbed fragments than in the three larger fragments. Understory species density was highest in the highly disturbed 18‐ha fragment, due to weedy invasive species occurring with rain forest plants. Nonmetric multidimensional scaling and Mantel tests revealed significant and similar patterns of floristic variation suggesting similar effects of disturbance on community compositional change for the three life‐forms. The five fragments encompassed substantial plant diversity in the regional landscape, harbored at least 70 endemic species (3.21% of the endemic flora of the Western Ghats–Sri Lanka biodiversity hotspot), and supported many endemic and threatened animals. The study indicates the significant conservation value of rain forest fragments in the Western Ghats, signals the need to protect them from further disturbances, and provides useful benchmarks for restoration and monitoring efforts.
Secondary Succession and Indigenous Management in Semideciduous Forest Fallows of the Amazon Basin1
Authors: Toledo Marisol , Salick Jan
Published: December 2005

To the discussion on secondary succession in tropical forests, we bring data on three under‐addressed issues: understory as well as overstory changes, continuous as opposed to phase changes, and integration of forest succession with indigenous fallow management and plant uses. Changes in vegetation structure and species composition were analyzed in secondary forests following swidden agriculture in a semideciduous forest of Bolivian lowlands. Twenty‐eight fallows, stratified by four successional stages (early = 1–5 yr, intermediate = 6–10 yr, advanced = 12–20 yr, and older = 22–36 yr), and ten stands of mature forests were sampled. The overstory (plants ≥5 cm diameter at breast height [DBH]) was sampled using a 20 × 50 m plot and the understory (plants <5 cm DBH) in three nested 2 × 5 m subplots. Semistructured interviews provided information on fallow management. Canopy height, basal area, and liana density of the overstory increased with secondary forest age. The early stage had the lowest species density and diversity in the overstory, but the highest diversity in the understory. Species composition and abundance differentiated mature forests and early successional stage from other successional stages; however, species showed individualistic responses across the temporal gradient. A total of 123 of 280 species were useful with edible, medicinal, and construction plants being the most abundant for both over‐ and understories. Most of Los Gwarayo preferred mature forests for making new swidden, while fallows were valuable for crops, useful species, and regenerating timber species.
Distribution of gamma-ray burst ejecta energy with Lorentz factor
Authors: Granot Jonathan , Kumar Pawan
Published: December 2005

The early X-ray afterglow for a significant number of gamma-ray bursts detected by the Swift satellite is observed to have a phase of very slow flux decline with time (Fν ∝ t−α with 0.2 ≲α≲ 0.8) for 102.5≲t≲ 104 s, while the subsequent decline is the usual 1 ≲α3≲ 1.5 behaviour, which was seen in the pre-Swift era. We show that this behaviour is a natural consequence of a small spread in the Lorentz factor of the ejecta, by a factor of ∼2–4, where the slower ejecta gradually catch up with the shocked external medium, thus increasing the energy of the forward shock and delaying its deceleration. The end of the ‘shallow’ flux decay stage marks the beginning of the Blandford–McKee self-similar external shock evolution. This suggests that most of the energy in the relativistic outflow is in material with a Lorentz factor of ∼30–50.
Standards of Validity and the Validity of Standards in Performance Asessment
Authors: Messick Samuel
Published: December 2005

What are six distinct aspects of construct validation? How do these aspects apply to performance assessment? Are the consequences of performance assessment on teaching and learning relevant to construct validation?
Generalizability of Performance Assessments
Authors: Brennan Robert L. , Johnson Eugene G .
Published: December 2005

How can the contributions of raters and tasks to error variance be estimated? Which source of error variance is usually greater? Are interrater coefficients adequate estimates of reliability? What other facets contribute to unreliability in performance assessments?
Setting Standards for Complex Performances: An Iterative, Judgmental Policy capturing Strategy
Authors: Jaeger Richard M.
Published: December 2005

What is judgmental policy capturing? How can it be applied to standard setting with performance assessments? Do judges value some exercises more in setting standards?
Unintended Consequences of Perfiormance Assessment: Issues of Bias and Fairness
Authors: Bond Lloyd
Published: December 2005

Have advances in testing historically had unexpected consequences? How have African Americans fared on recent performance assessments? How can fairness of performance assessments be ensured?
Commentary on Values and Standards in Performance Assessment
Authors: Guion Robert M.
Published: December 2005

Is construct validity relevant to performance assessment? Can these assessments allow meaningful comparisons? How can we minimize validity‐reducing errors?
Myocardial Strain Analysis in Acute Coronary Occlusion
Authors: Lyseggen Erik , Skulstad Helge , Helle-Valle Thomas , Vartdal Trond , Urheim Stig , Rabben Stein Inge , Opdahl Anders , Ihlen Halfdan , Smiseth Otto A.
Published: December 2005

Background—

This study proposes 2 new echocardiographic indices with potential application in acute coronary artery occlusion to differentiate between viable and necrotic myocardium and to identify reperfusion. We investigated whether the ratio between systolic lengthening and combined late and postsystolic shortening (L-S ratio) could identify viable myocardium and whether systolic myocardial compliance, calculated as systolic lengthening divided by systolic pressure rise, could identify necrotic myocardium.

Methods and Results—

In anesthetized dogs, we measured left ventricular (LV) pressure and long-axis strain by Doppler echocardiography (SDE) and sonomicrometry. The left anterior descending coronary artery was occluded for 15 minutes with 3-hour reperfusion (n=6), for 4 hours with 3-hour reperfusion (n=6), or for 4 hours with no reperfusion (n=6). Myocardial work was quantified by pressure–segment length analysis, necrosis by triphenyltetrazolium chloride staining, and edema by water content. L-S ratio and systolic compliance were calculated by SDE. The L-S ratio ranged between 0.00 and 1.00 and was well correlated with regional myocardial work (
r
=0.77,
P
<0.0001). In entirely passive myocardium, the L-S ratio approached 1 and was similar in viable (0.88±0.02) and necrotic (0.81±0.03) myocardium. Compliance, however, was reduced in necrotic myocardium owing to edema (0.07±0.01%/mm Hg) but was preserved in viable myocardium (0.15±0.01%/mm Hg,
P
<0.05). Reperfusion of viable myocardium caused a reduction of the L-S ratio after 15 minutes (0.57±0.06,
P
<0.05), reflecting recovery of function. Reperfusion of necrotic myocardium caused no change in the L-S ratio, but compliance was further reduced within 15 minutes (0.03±0.01%/mm Hg,
P
<0.05).

Conclusion—

Myocardial L-S ratio and compliance by SDE identified active contraction and necrosis, respectively. These indices should be tested clinically for assessment of myocardial viability and reperfusion.
Comparison of Valve Structure, Valve Weight, and Severity of the Valve Obstruction in 1849 Patients Having Isolated Aortic Valve Replacement for Aortic Valve Stenosis (With or Without Associated Aortic Regurgitation) Studied at 3 Different Medical Centers in 2 Different Time Periods
Authors: Roberts William Clifford , Ko Jong Mi , Hamilton Cody
Published: December 2005

Background—

Aortic valve replacement (AVR) for patients with aortic stenosis (AS) has now been available for 45 years. During this period, indications for the procedure have changed.

Methods and Results—

Operatively excised stenotic aortic valves (with or without associated aortic regurgitation and without associated mitral valve disease) from 3 different medical centers (National Institutes of Health, Georgetown University Medical Center, and Baylor University Medical Center) were examined during 2 different time periods by the same physician to compare aortic valve structure, valve weight, age at operation, preoperative transvalvular peak pressure gradient, calculated aortic valve area, and whether simultaneous coronary artery bypass grafting (CABG) was performed. Compared with the first 3 decades (1961–1990) of AVR, patients having this operation during the fourth and fifth decades (1991–2004) had a lower frequency of congenitally malformed aortic valves, a higher frequency of tricuspid aortic valves, an older age, valves of lighter weight and lower transvalvular peak pressure gradients, and more often simultaneous CABG.

Conclusions—

Although patients having isolated AVR for AS in the present and last decade were older than in the first 3 decades of valve replacement surgery, congenitally malformed aortic valves continue to be more common than tricuspid aortic valves, but the degree of AS and therefore, valve weight was significantly lower than in the earlier decades.
What a Cardiologist Needs to Know About Patients With Human Immunodeficiency Virus Infection
Authors: Hsue Priscilla Y. , Waters David D.
Published: December 2005

Patient case:

A 48-year-old man with human immunodeficiency virus (HIV) infection developed chronic chest pain that started after a bout of pneumonia. He has hypertension and has smoked cigarettes in the past. His current medications include Kaletra and Combivir. His total cholesterol was 331 mg/L, his HDL cholesterol was 27 mg/L, his triglycerides were 935 mg/L, and his LDL cholesterol could not be calculated. How should this patient be evaluated and managed?
Retinal and Cerebral Microembolization During Coronary Artery Bypass Surgery
Authors: Ascione Raimondo , Ghosh Arup , Reeves Barnaby C. , Arnold John , Potts Mike , Shah Atul , Angelini Gianni D.
Published: December 2005

Background—

We sought to compare the effects on ophthalmic function of coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB) and off-pump (OPCAB) grafting and to investigate whether retinal microvascular damage is associated with markers of cerebral injury.

Methods and Results—

Retinal microvascular damage was assessed by fluorescein angiography and color fundus photography. Ophthalmic function was tested by the logarithm of the minimum angle of resolution visual acuity (VA), and cerebral injury, by transcranial Doppler ultrasound–detected emboli and S100 protein values. Twenty patients were randomized. Fluorescein angiography and postoperative VA could not be obtained for 1 CABG-CPB patient. Retinal microvascular damage was detected in 5 of 9 CABG-CPB but in none of 10 OPCAB patients (risk difference, 55%; 95% confidence interval [CI], 23% to 88%;
P
=0.01). Color fundus photography detected microvascular damage in 1 CABG-CPB patient but in no OPCAB patients; this lesion was associated with a field defect, which remained after 3 months of follow-up. There was no difference in postoperative VA. Doppler high-intensity transient signals (HITS) were 20.3 times more frequent in the CABG-CPB than in the OPCAB group (95% CI, 9.1 to 45;
P
<0.0001). Protein S100 levels were higher in the CABG-CPB than in the OPCAB group 1 hour after surgery (
P
<0.001). HITS were 14.7 times more frequent (95% CI, 3.5 to 62;
P
=0.001) and S100 level 2.1 times higher (95% CI, 1.3 to 3.5;
P
=0.005) when retinal microvascular damage was present.

Conclusions—

The relative frequency of retinal microvascular damage between groups shows the extent to which the risk of cerebral injury is reduced with OPCAB. Imaging of part of the cerebral circulation provides evidence to validate markers of cerebral injury.
Binge Drinking and Mortality After Acute Myocardial Infarction
Authors: Mukamal Kenneth J. , Maclure Malcolm , Muller James E. , Mittleman Murray A.
Published: December 2005

Background—

Moderate drinkers have a lower risk of mortality after myocardial infarction (MI). Although binge drinking has been associated with a higher risk of MI in some studies, its relation to prognosis after MI is uncertain.

Methods and Results—

In a prospective, inception cohort study conducted at 45 US hospitals, 1935 patients hospitalized with a confirmed MI between 1989 and 1994 underwent detailed personal interviews. Patients reported their usual frequency of binge drinking of beer, wine, and liquor, defined as intake of 3 or more drinks within 1 to 2 hours, and were followed up for mortality for a median of 3.8 years. Of 1919 eligible patients, 250 (94% men) reported binge drinking during the prior year, and a total of 318 patients died during follow-up. Binge drinkers had a 2-fold higher risk of mortality than drinkers who did not binge (hazard ratio, 2.0; 95% confidence interval, 1.3 to 3.0). A comparison of 192 binge drinkers and 192 other patients matched on propensity scores yielded a similar result. The association between binge drinking and total mortality tended to be similar among patients whose usual alcohol intake was light or heavier and for binge drinkers who consumed beer, wine, or liquor. Usual alcohol intake was inversely associated with mortality, but binge drinking completely attenuated this relation.

Conclusions—

Our results suggest that alcohol consumption may be linked to potential hazards among patients who survive acute MI. Although moderate intake has been associated with lower mortality, binge drinking, even among light drinkers, appears to be associated with 2-fold higher mortality.
Cultural politics in Korea’s contemporary films under neoliberal globalization
Authors: Jin Dal Yong
Published: December 2005

The Korean film business has witnessed a swift and steady growth in the production of, and audiences for, domestic films over the past several years. This article attempts to clarify the cause of these changes and goes on to discuss the Korean film industry with a special focus on state cultural policy. The article then explicates the impact of the changing cultural policy on the film business by examining the influx of domestic capital into the film industry. It also analyzes the impact of neoliberal cultural policies on the transnationalization of the Korea film industry. Finally, it discusses whether changing cultural policies have maintained or developed cultural identity, such as Korean traditions and nationalism, in domestic films.
A developing market in news: Xinhua News Agency and Chinese newspapers
Authors: Xin Xin
Published: December 2005

The mythology of the news agency, as the earliest news organization to operate globally, has been used to explain its ability to build up connections with its counterparts, and media and non-media organizations, as well as to use these connections to good advantage. This article offers a social-historical analysis of China’s Xinhua News Agency and Chinese newspapers, focusing on their interrelations. It attempts to delineate how a national news agency in a non-capitalist country went through a process of development, and how it has changed during the transition from a command economy to market-oriented economy. Xinhua’s experience of dealing with newspapers provides a distinctive example: it started life as an amalgamation of an agency and several newspapers and then evolved towards the path followed by a great number of news agencies since the 19th century. The movement of Xinhua towards adopting Western experiences illustrates a globalized tendency, which has been experienced by leading international news agencies and is still experienced by a number of national players in the developing world. This tendency leads news agencies, including Xinhua, to undergo a transition from bi-directional dependency to an agency-client relationship.
Changes in the self resulting from the use of mobile phones
Authors: García-Montes José M. , Caballero-Muñoz Domingo , Pérez-Álvarez Marino
Published: December 2005

The present work examines the potential consequences of the use of mobile telephones on people’s behaviour and identity. In doing so, we start from the premise that, even though this technology may have different effects in different cultural contexts, it promotes and foments certain patterns of behaviour and of understanding one’s own identity. It is suggested that this new identity goes hand in hand with a spatial-temporal recomposition of the context in which actions take place. On the opening up of an almost continuous virtual space, conflicts may arise between the different roles played by an individual which were previously differentiated as a function of space. Similarly, increased flexibility in arrangements leads to the appearance of a new concept of time, which we might call the ‘present extensive’. We also discuss the possible superstitions the use of this new technology may bring with it. As a result of these analyses, it is considered that the mobile phone not only emerges within a postmodern society, but also, along with other technological developments, feeds a postmodern mentality.
Democratic media activism through the lens of social movement theory
Authors: Carroll William K. , Hackett Robert A.
Published: December 2005

This article considers how we are to understand democratic media activism, which has recently burgeoned in Canada, the UK and the USA. What is its political significance and potential? Is it a new social movement, a new style of politics cutting across movements, or are new concepts needed? Drawing illustratively upon interviews with media activists, notably in Vancouver, we explore insights offered by social movement theory - including resource mobilization formulations and the new social movement theories of Melucci, Habermas, Cohen and Arato, and Fraser. While all these traditions offer valuable insights, media activism reveals limitations in existing conceptualizations. It has some of the characteristics of a movement, but lacks a distinct collective identity or niche within movement ecology. It may be destined to be a boundary-transgressing nodal point for other movements, articulating a coherent project for radical democracy, rather than a movement-for-itself.
Symbiotic transformations: youth, global media and indigenous culture in Malta
Authors: Grixti Joe
Published: December 2005

The article explores the impact of global commercial media on young people’s developing perceptions of their own cultural identity. It works from the premise that local cultures are not so much getting replaced by ‘global culture’ as inflecting it by coexisting with it. The discussion draws on data collected in the course of focus group interviews with young adults living in the Mediterranean island of Malta, in order to stress the specificity with which young people from different cultural contexts consume global media. I argue that, as in other postcolonial communities, though the choices available to Maltese youth have become strongly inflected (or ‘hybridized’) by the commercial imperatives of global media, the ways in which they are appropriated and played out retain very idiosyncratic characteristics, which mark them out as uniquely Maltese.
Obstacles to the success of female journalists in Korea
Authors: Kim Kyung-Hee
Published: December 2005

This article focuses on the mechanisms that exclude female journalists from the news production process, and on their alienation in modern Korean society. Using a content analysis of essays by Korean female journalists, the study found exclusion mechanisms of female journalists from (1) the news gathering process, including ‘authoritative information collection’, ‘unethical compromise culture’, ‘informal communication’ and the ‘traditional view of womanhood’; (2) the newsroom, including ‘masculine bonds’, ‘distrust of female journalists’ and the ‘stereotype of female journalists’; and (3) the private area, including housework, pregnancy and childcare. The alienation of female journalists was also studied at the organizational and personal levels. At the organizational level, the result shows that female journalists are both horizontally and vertically marginalized. At the personal level, the self-alienation of female journalists was attributed to the fact that they have less access to in-depth information because of the division of work based on gender.
The Lost Roots of the Theory of Group Analysis: ‘Taking Interrelational Individuals Seriously’!
Authors: Lavie Joshua
Published: December 2005

This paper is a micro-historical analysis of unpublished drafts of S.H. Foulkes – intended to be part of his ‘Theory Book’ on group analysis – together with a comprehensive new historical reading of Norbert Elias's published writings relevant to group analysis, focusing on two lost roots of the theory of group analysis: (1) Elias's discovery of the simultaneous-interdependent process of ‘Individualization and Socialization’, and (2) Foulkes's innovative conception of the ‘mind as a multi-personal phenomenon’. This analysis forms the main argument of this paper – that the theory of group analysis ‘takes interrelational individuals (in the plural) seriously’, not the reified concept of ‘The Individual’ nor the abstract concept of ‘The Group’. It is proposed that Foulkes's conception of the individual's mind ‘as a multi-personal phenomenon’ is compatible, albeit, preceded Mitchell's ‘relational’ conception of ‘multiple selves’.
Evaluating Experience: The Manchester Course in Group Psychotherapy
Authors: Bacha Claire S.
Published: December 2005

How do psychotherapy students experience learning in groups? To answer this question, the Manchester Course in Group Psychotherapy asked its students to evaluate and describe their experiences over a period of six years. The results show that learning in psychotherapy is both painful and rewarding. Much change can be made in 30 weeks of a group experiential learning situation. But, most importantly, an analytic group is an excellent setting for learning about psychotherapy.
The Image of the Self in the Mirror of the Supervising Group
Authors: Kouneli Ersi
Published: December 2005

This article refers to the ‘Greek Model of Supervision’, as practised at the Institute of Group Analysis (IGA) Athens and focuses on the relationship between a therapeutic group and its supervising group. This relationship includes the interaction between various persons and factors such as participating students, the presenter, the description of the therapeutic group being presented, the experienced observer and the mutual relationships of all. This network of interactions promotes the reflection of multiple mirror phenomena between the two groups and facilitates their exploration, understanding and studying as well as their developmental and therapeutic effect at many levels of inter-relations.
Hydroxyapatite-TiO2 Hybrid Coating on Ti Implants
Authors: Lee Su-Hee , Kim Hae-Won , Lee Eun-Jung , Li Long-Hao , Kim Hyoun-Ee
Published: December 2005

A hydroxyapatite (HA)-titania (TiO2) hybrid coating is developed to improve the biocompatibility of titanium (Ti) implants. The HA predeposited layer on Ti via electron beam (e-beam) evaporation is subsequently treated by micro-arc oxidation (MAO) to produce an HA-TiO2 hybrid layer on Ti. The e-beam-deposited HA layer has a thickness of ≈1 μm and was highly dense prior to MAO. By means of MAO treatment, a rough and porous TiO2 layer is formed beneath the HA layer with a simultaneous local dissolution of the HA layer. Due to the HA precoating, high concentrations of Ca and P are preserved on the coating surface. The osteoblast-like cells on the hybrid coating layer grow and spread favorably. The cell proliferation rate on the hybrid coatings is not much different from that on pure Ti or simple MAO-treated Ti. However, the alkaline phosphatase (ALP) activity of the cells is significantly higher ( p < 0.05) on the HA-TiO2 hybrid coatings than on either the pure Ti or the simple MAO-treated specimen, suggesting that the cellular activity on the hybrid coatings is improved.
The Effect of Hyaluronic Acid-supplemented Bone Graft in Bone Healing: Experimental Study in Rabbits
Authors: Aslan Muzaffer , Şimşek Göksel , Dayi Ertunç
Published: December 2005

Hyaluronic acid (HA) is one of the essential components of extracellular matrix, which plays a predominant role in tissue morphogenesis, cell migration, differentiation, and adhesion. Bone allografts are frequently used to repair and reconstruct bone defects. In this study, two cavities of 3 mm diameter and depth have been created in the right tibia of 30 mature rabbits in accordance with the principles of general surgery. One of the cavities in the tibia is filled with HA and bone graft and the other is filled with only spongiosal bone graft, for the purpose of control. On the 20th, 30th, and 40th days, rabbits have been sacrificed in equal numbers and defective regions have been extracted. The Kruskal-Wallis test was applied to the data obtained in the result of histopathologic survey of specimens. In conclusion, the cavities that have been filled with HA and bone graft have shown higher scores than the control group during every period of the study.
Synthesis and Evaluation of Novel Bifunctional Oligomer-based Composites for Dental Applications
Authors: Xie Dong , Chung Il-Doo , Wang Guigui , Mays Jimmy
Published: December 2005

Five novel bifunctional oligomers containing both carboxylic acid and methacrylate groups are synthesized, characterized, and used to formulate compomers by mixing with strontium fluoroaluminosilicate glass powder at a filler level of 75% (by weight). Compressive strength (CS) of the cements and viscosity of the resin liquids are used as screening tools to find the optimal formulation. Diametral tensile (DTS) and flexural strengths (FS) are also determined. Results show that the oligomers derivatized with glycerol dimethacrylate exhibit higher CS than those with 2-hydroxyethyl methacrylate. The CS increases with increasing diluent content, filler level, and light-exposure time. During aging, the cement shows an increase of strength over 24 h and then remains unaltered for up to 3 months. The experimental compomer is 45 and 69% higher in CS, 35 and 174% higher in DTS, and 39 and 170% higher in FS, respectively, as compared to Dyract and Fuji II LC.
In vivo Performance of Biodegradable Calcium Phosphate Glass Ceramics using the Rabbit Model: Histological and SEM Observation
Authors: Dias A. G. , Lopes M. A. , Santos J. D. , Afonso A. , Tsuru K. , Osaka A. , Hayakawa S. , Takashima S. , Kurabayashi Y.
Published: December 2005

Two MK5 (45CaO-45P2O5-5MgO-5K2O, in mol%) and MT13 (45CaO-37P2O5-5MgO-13TiO2, in mol%) glasses are prepared in the meta- and pyrophosphate regions and crystallized to obtain MK5B and MT13B, respectively. MK5B was obtained by controlled crystallization, and MT13B by powder sintering. As a result of these heat treatment processes, the crystalline phases precipitated in the glassy matrix are KCa(PO3)3, β-Ca(PO3)2, β-Ca2P2O7 and Ca4P6O19 phases for MK5B and CaTi4(PO4)6, TiP2O7, α- and β-Ca2P2O7 phases for MT13B. To assess the in vivo biological behavior of these glass ceramics, a mixed granulometry in the range 250-355 μm and 355-425 μm with a ratio of 1/1 was implanted for 2, 4, and 12 weeks in the tibiae of Japanese white rabbits. The results showed that the in vivo behavior was strongly affected by their solubility. All implanted materials, MK5B and MT13B, and β-tricalcium phosphate (β-TCP) as control material, showed signs of degradation in vivo. However, the levels of degradation were quite different throughout the implantation periods. The highest degradation was observed for MK5B glass ceramic and the lowest for MT13B with β-TCP in-between. All implanted materials allow for new bone formation in the bone defect area. At the longest implantation period (12 weeks), the MT13B and β-TCP materials were almost completely surrounded by new bone tissue, whereas MK5B showed some unfilled spaces. This behavior is discussed in terms of the high degradation observed in previous studies.
Modifications on Collagen Structures Promoted by 1,4-Dioxane Improve Thermal and Biological Properties of Bovine Pericardium as a Biomaterial
Authors: Forti Fábio L. , Goissis Gilberto , Plepis Ana M. G.
Published: December 2005

Collagen is a widely used raw material for biomaterial manufacture, which generally depends on chemical modifications of this fibrillar protein with cross-linking agents to improve biocompatibility and mechanical properties. However, cross-linking reduces the natural properties of collagen, such as low immune response, low toxicity as well as the ability to promote cellular growth and attachment. In this work, the modifications promoted by 1,4-dioxane solvent on the collagen present in native bovine pericardium (NBP) matrix routinely used in bioprosthesis manufacture, with or without subsequent cross-linking by glutaraldehyde, has been studied. The structural changes of NBP evaluated by scanning electron microscopy show that 1,4-dioxane induces a more homogeneous material by increasing aggregation of collagen fibers, while transmission scanning electron microscopy shows that natural collagen fibril arrangement, integrity, and the D-periodicity pattern are maintained by solvent treatments. Measurements of thermal stability and resistance to collagenase enzymatic digestion of NBP matrices treated with 1,4-dioxane show an increase in melting temperature and decrease in biodegradability, as compared to native pericardium. Cross-linking with glutaraldehyde improves all the analyzed NBP properties, which are not impaired by previous treatment with 1,4-dioxane. Histological evaluation of NBP submitted to 1,4-dioxane treatment shows lower lipid and cell contents and improvement in other morphologic characteristics compared to native pericardium. Altogether, these results suggest the use of 1,4-dioxane organic solvent as an alternative non-cross-linking treatment for direct utilization on rich collagen matrices, resulting in materials with improved biocompatibility and physicochemical properties suitable for tissue engineering.
Effect of Ganciclovir on the Hydrolytic Degradation of Poly(lactide-co-glycolide) Microspheres
Authors: Chen X. , Ooi C. P. , Lim T. H.
Published: December 2005

Ganciclovir (GCV)-loaded poly(lactide-co-glycolide) (PLGA) microspheres, 125 ± 11 μm in diameter, are produced using the emulsification/solvent evaporation technique. The release rate of the drug is studied for 20 weeks in a phosphate-buffered solution of pH 7 at 37°C. The release of the drug shows a triphasic release pattern, i.e., an initial burst, a diffusive phase, and a second burst. The initial burst occurs within the first 2 days of immersion. After the burst, the release is by diffusion for up to 13 weeks, followed by another burst release, which signals the onset of bulk degradation of the PLGA polymer. The presence of GCV molecules decreases the hydrolytic rate of PLGA degradation. Gel permeation chromatography (GPC), differential scanning calorimetry (DSC), field emission scanning electron microscopy (FESEM), and ultraviolet (UV) spectroscopy are used to assess the hydrolytic degradation and drug release rate of the microspheres.
Constituting the Feminist Subject in Poststructuralist Discourse
Authors: Davies Bronwyn , Browne Jenny , Gannon Susanne , Hopkins Lekkie , McCann Helen , Wihlborg Monne
Published: December 2005

In this article, we describe a collective biography that we convened in order to revisit the site of the radical theoretical break with the liberal humanist individual marked by the poststructuralist work of Henriques and colleagues and the feminist poststructuralist work of Weedon. These writers suggest that the new subject of poststructuralist theory will be more open to the changes desired by feminist and social justice movements. They describe the break with the liberal humanist subject as a break that heralds new possibilities of personal and cultural transformation. In this article, using the medium of collective biography stories, we revisit the relation between the liberal humanist individual and the transformative possibilities poststructuralist writers envisaged for the new subject of poststructuralism. We situate the discussion in the context of our transformation into neoliberal subjects over the last three decades.
Analysis of Strains in Baked Clay Based Materials During Freezing and Thawing Cycles
Authors: Wardeh G. , Perrin B.
Published: December 2005

In order to better understand the freezing mechanisms of baked clay materials, the strains of two types of tiles were observed during freezing and thawing cycles. The saturated medium began to contract, at first practically linearly, then water froze progressively between 0 and -10°C, and finally contraction became linear again for lower temperatures. Calorimetric measurements showed that the heterogeneous nucleation phenomenon was dominant. With the help of a hypothesis, the variation of the volumetric fraction of ice with temperature was determined. In the strains observed during the freezing period, the part due to temperature effects was separated from the part due to internal pressures produced by water and ice. Biot’s model then allowed the internal pressure generated by water and ice to be calculated as a function of temperature. The difference in behavior of the two materials was thus proved.
On the Hysteresis in Moisture Storage and Conductivity Measured by the Instantaneous Profile Method
Authors: Plagge Rudolf , Scheffler Gregor , Grunewald John , Funk Max
Published: December 2005

The relative humidity (or the capillary pressure) and volumetric water content can be determined at specific locations inside a porous medium by means of the proposed instantaneous profile method (IPM). The measurements are carried out with temperature and relative humidity (RH) sensors as well as with time domain reflectometry probes during the whole duration of the experiment. Thus, the IPM allows a transient measurement of the moisture retention characteristic. In addition, from the spatial and temporal distributions of moisture content and RH one may calculate the moisture conductivity as a function of moisture content and RH as well.

The adsorption and successive desorption experiments presented in this article have been performed on calcium silicate (a capillary active material). The results show a hysteretic behavior that appears to depend on the nature of the process. The moisture conductivity as function of RH shows a significant hystereses; however, the moisture conductivity in relation to the moisture content appears to be non-hysteretic.
Statins and osteoporosis: new role for old drugs
Authors: Jadhav Satyawan B , Jain Girish Kumar
Published: December 2005

Osteoporosis is the most common bone disease, affecting millions of people worldwide and leading to significant morbidity and high expenditure. Most of the current therapies available for its treatment are limited to the prevention or slowing down of bone loss rather than enhancing bone formation. Recent discovery of statins (HMG-CoA reductase inhibitors) as bone anabolic agents has spurred a great deal of interest among both basic and clinical bone researchers. In-vitro and some animal studies suggest that statins increase the bone mass by enhancing bone morphogenetic protein-2 (BMP-2)-mediated osteoblast expression. Although a limited number of case—control studies suggest that statins may have the potential to reduce the risk of fractures by increasing bone formation, other studies have failed to show a benefit in fracture reduction. Randomized, controlled clinical trials are needed to resolve this conflict. One possible reason for the discrepancy in the results of preclinical, as well as clinical, studies is the liver-specific nature of statins. Considering their high liver specificity and low oral bioavailability, distribution of statins to the bone microenvironment in optimum concentration is questionable. To unravel their exact mechanism and confirm beneficial action on bone, statins should reach the bone microenvironment in optimum concentration. Dose optimization and use of novel controlled drug delivery systems may help in increasing the bioavailability and distribution of statins to the bone microenvironment. Discovery of bone-specific statins or their bone-targeted delivery offers great potential in the treatment of osteoporosis. In this review, we have summarized various preclinical and clinical studies of statins and their action on bone. We have also discussed the possible mechanism of action of statins on bone. Finally, the role of drug delivery systems in confirming and assessing the actual potential of statins as anti-osteoporotic agents is highlighted.
Preliminary investigation of the nasal delivery of liposomal leuprorelin acetate for contraception in rats
Authors: Shahiwala Aliasgar , Misra Ambikanandan
Published: December 2005

The purpose of the study was to investigate the nasal route as a non-invasive alternative for delivery of leuprorelin acetate (leuprolide acetate, LEU) and to achieve an effective concentration of leuprorelin acetate in blood after nasal administration for contraception in rats. The plain drug solution, physical mixture (plain drug along with constituents of liposomes), or drug encapsulated in either neutral or charged liposomes containing 5 μg leuprorelin acetate were administered to rats through the nasal route. The plain drug solution was administered subcutaneously (s.c.). Simultaneous evaluation was performed on the influence of a mucoadhesive agent (chitosan) on nasal absorption of the plain drug and the liposome-encapsulated drug. Blood samples were taken at regular time intervals and subjected to luteinising hormone (LH) analysis using a specific immunoassay kit. The plasma luteinising hormone concentration vs time data of nasal and subcutaneous treatments were plotted and compared with that of subcutaneous administration. Relative percentage of bioavailability (F) for nasal treatments was calculated from plasma concentration vs time plots. Sperm count and fertility performance studies were carried out for selected formulations in rats. Neutral liposomes (LLEU) and negatively-charged liposomes (LLEUn) showed higher relative percentage of bioavailability (F 27.83 and 21.30%, respectively) as compared with the plain drug and the physical mixture (F 10.89 and 10.96%, respectively) after nasal administration. Hence, work on neutral liposomes was continued. F was further improved after incorporation of chitosan i.e. 10.89 to 49.13% for plain leuprorelin acetate and 27.83 to 88.90% for liposomal leuprorelin acetate formulations. Liposomal chitosan formulation administered nasally and leuprorelin acetate solution subcutaneously achieved complete azoospermia. No implantation sites were observed after the mating of female rats with treated males. It was observed that in the treated female rats, the estrous cycles ceased with the same formulations from the first treatment cycle. The findings of these investigations demonstrated that the bioavailability of the nasally-administered liposomal leuprorelin acetate with chitosan formulation was comparable with that of the subcutaneously administered drug. Complete contraception was obtained in male and female rats that had been treated with either the nasally administered liposomal leuprorelin acetate with chitosan or the subcutaneously administered drug.
Effect of the co-occurring components from green tea on the intestinal absorption and disposition of green tea polyphenols in Caco-2 monolayer model
Authors: Zhang Li , Chow Moses S S , Zuo Zhong
Published: December 2005

This study aimed to investigate the effect of co-occurring components from green tea on the intestinal absorption and disposition of green tea polyphenols (GTPs) using the Caco-2 cell monolayer model. The absorption and secretion transport of the four GTPs, in the form of individual pure compounds, pure compound mixtures and green tea extract, were studied in the Caco-2 cell model. Four GTPs and their metabolites were analysed by HPLC/MS and HPLC coupled with electrochemical detector. The apparent permeability coefficients (Papp) of each compound, as well as the metabolites (mainly sulfation and methylation conjugates) generated, were compared for the different dosing formulations utilized. The results showed that the absorption transport of the four GTPs in different dosing formulations was similar. However, the secretion transport profiles of (-)-epicatechin (EC), (-)-epigallocatechin (EGC) and (-)-epigallocatechin gallate (EGCG) were altered when the GTP mixture was administered. It was suggested that transporter competition resulting in reduced efflux of EC, as well as metabolic competition resulting in reduced formation of EGC sulfate and methylated EGC sulfate, might be involved during the secretion transport of GTP mixture.
Effects of Transcutol P on the corneal permeability of drugs and evaluation of its ocular irritation of rabbit eyes
Authors: Liu Zhidong , Nie Shufang , Guo Hong , Pan Weisan , Li Jiawei
Published: December 2005

Our purpose was to explore the use of Transcutol P (Trans) in an ocular drug delivery system. The effect of Trans on the corneal permeability of drugs was investigated in-vitro, using isolated rabbit corneas. The ocular irritation of Trans was also tested in rabbits in-vivo. In the presence of Trans, at a concentration of 0.005–0.03%, the maximum increase in the apparent permeability coefficient (Papp) was 1.5, 1.5, 3.0 and 3.3 fold for ribavirin, gatifloxacin, levofloxacin hydrochloride and enoxacin, respectively. However, the Papp value of oxaprozin was reduced in the presence of Trans. The maximum reduction was found to be 2.8 fold at a concentration of 0.03% Trans. The results of the ocular irritation studies showed that Trans was non-irritant at the concentrations studied (0.005–0.03%), while it produced slight irritation at a concentration of 0.05%. It was also found that Trans did not cause any visible ocular damage or abnormal clinical signs involving the cornea, iris or conjunctivae at all concentrations. We concluded that Trans may have potential clinical benefits in improving the ocular drug delivery of hydrophilic compounds.
Chlorzoxazone metabolism is increased in fasted Sprague-Dawley rats
Authors: Wan Jie , Shoaf Susan E , Ernstgård Lena , Song Byoung J
Published: December 2005

Earlier data showed that men fasted for 38 h had a reduced rate of chlorzoxazone metabolism, suggesting a decreased level of cytochrome P450 2E1 (CYP2E1). In contrast, the level of CYP2E1 in fasted rats had been shown to be elevated. In this study, we have investigated whether chlorzoxazone metabolism in fasted rats was changed by determining the pharmacokinetics of chlorzoxazone and its metabolite, 6-hydroxychlorzoxazone (6-OHCZ), as a CYP2E1 probe, and by measuring liver CYP2E1 using immunoblot techniques. Chlorzoxazone was administered by gavage (50 mg kg−1) or intravenously (25 mg kg−1) to control (nine for oral and three for intravenous) and 24 h-fasted (nine for oral and four for intravenous) male Sprague-Dawley rats. Following sampling of blood through a jugular vein cannula, chlorzoxazone and 6-OHCZ plasma concentrations were measured by HPLC with UV detection. Pharmacokinetic parameters for chlorzoxazone and 6-OHCZ in each treatment group were determined by model fitting and non-compartmental analysis. In parallel with the increased liver CYP2E1 level, the elimination of chlorzoxazone and 6-OHCZ was significantly increased in fasted rats in the oral and the intravenous study. A multiple analysis of variance covariance analysis and a multiple regression analysis revealed a significant correlation between 1/t½ and CYP2E1 level and aniline hydroxylase activity. However, the correlation between 1/t½ and pentoxyresorufin O-dealkylase, ethoxyresorufin O-dealkylase and erythromycin N-demethylase was not significant. Therefore the contribution of other P450s to chlorzoxazone metabolism seemed to be minor in the concentration range that we tested. In conclusion, fasting rats for 24 h caused a measurable induction of CYP2E1, which produced a significant increase in the rate of chlorzoxazone metabolism and elimination.
Carbamazepine uptake into rat brain following intra-olfactory transport
Authors: Barakat N S , Omar S A , Ahmed A A E
Published: December 2005

Targeting the brain via nasal administration of drugs has been studied frequently over the last few years. In this study, a suitable gel formulation was designed to provide the absorption of a highly lipophilic drug through nasal mucosa. For this purpose, carbamazepine was chosen as the model drug. Hypromellose and Carbopol were used as mucoadhesive polymers in the formulation to increase the residence time of the gel on the mucosa. The objective of this study was to confirm the existence of a transport pathway for a drug (carbamazepine) to the brain directly from the nasal cavity, by comparing the concentration of drug in the brain after intranasal (i.n.), intravenous (i.v.), and oral (p.o.) administration. A statistically significant high level of the drug was found in the brain following intranasal administration compared with the intravenous and oral routes. These findings suggested the existence of a direct transport pathway for carbamazepine from the nasal cavity to the brain. This pathway may represent a new delivery route to the brain and central nervous system of such drugs which are needed in high and rapid concentration in the brain, especially in emergencies.
Characterisation and regulation of E2F-6 and E2F-6b in the rat heart: a potential target for myocardial regeneration?
Authors: Movassagh Mehregan , Bicknell Katrina A , Brooks Gavin
Published: December 2005

The E2F transcription factors are instrumental in regulating cell cycle progression and growth, including that in cardiomyocytes, which exit the cell cycle shortly after birth. E2F-6 has been demonstrated to act as a transcriptional repressor; however, its potential role in normal cardiomyocyte proliferation and hypertrophy has not previously been investigated. Here we report the isolation and characterisation of E2F-6 and E2F-6b in rat cardiomyocytes and consider its potential as a target for myocardial regeneration following injury. At the mRNA level, both rat E2F-6 and the alternatively spliced variant, E2F-6b, were expressed in E18 myocytes and levels were maintained throughout development into adulthood. Interestingly, E2F-6 protein expression was down-regulated during myocyte development suggesting that it is regulated post-transcriptionally in these cells. During myocyte hypertrophy, the mRNA expressions of E2F-6 and E2F-6b were not regulated whereas E2F-6 protein was up-regulated significantly. Indeed, E2F-6 protein expression levels closely parallel the developmental withdrawal of myocytes from the cell cycle and the subsequent reactivation of their cell cycle machinery during hypertrophic growth. Furthermore, depletion of E2F-6, using anti-sense technology, results in death of cultured neonatal myocytes. Taken together, abrogation of E2F-6 expression in neonatal cardiomyocytes leads to a significant decrease in their viability, consistent with the notion that E2F-6 might be required for maintaining normal myocyte growth.