bluuebunny/crossref_metadata_2025 huggingface dataset:
A preliminary investigation into tooth care, dental attendance and oral health related quality of life in adult stroke survivors in Tayside, Scotland
Authors: Hunter Romana V , Clarkson Jan E , Fraser Hazel W , MacWalter Ronald S
Published: August 2006

Objective:  The aim of this study was to investigate patterns of oral care, dental attendance and oral health‐related quality of life among adults who had suffered a stroke.

Background:  Stroke is the most common cause of adult disability in the UK. Seventy per cent of strokes occur in adults over 65 years of age. A mild stroke may leave little residual disability but in cases of moderate or severe stroke the disability may be significant and may impact on oral health and function.

Materials and methods:  A cross‐sectional survey was conducted among adults surviving 1 year after stroke, between January and July 2001. A medical screening was carried out which included an assessment of disability and handicap using the modified Rankin scale. A structured interview was conducted to identify normal patterns of oral care and dental attendance and to elicit if since suffering a stroke any changes had occurred or were likely to occur. The Short Form Oral Health Impact Profile (OHIP‐14) was administered prior to an oral examination. Analysis used SPSS 11.0 for Windows. Parametric and nonparametric tests were undertaken (t‐tests and chi‐squared tests with Yates correction where appropriate).

Results:  Forty‐one adults were recruited into the study comprising 21 female and 20 male. They ranged in age from 50 to 87 years and the mean age was 69 years (SD = 9.8). Forty per cent of participants experienced moderate disability or greater following their stroke. Thirty‐seven per cent had difficulty with tooth cleaning. The most frequently reported problem was being unable to use one hand properly as a result of the stroke. There was a significant association between the degree of disability following stroke and difficulty with tooth cleaning (P = 0.015). Disability as a result of the stroke was cited as the main reason for reported or projected attendance pattern change. The most frequently experienced OHIP‐14 dimension was functional limitation (39%).

Conclusion:  Individuals who have been left disabled after a stroke may require help with or advice on oral care and information on how to access dental services in a setting appropriate to their disability. Further research is needed to identify the dental needs of adults with stroke and to identify appropriate interventions to meet these needs.
Oral health care for frail elderly people: actual state and opinions of dentists towards a well‐organised community approach
Authors: De Visschere Luc M. , Vanobbergen Jacques N.
Published: August 2006

Objective:  This study was undertaken to provide an analysis of the actual oral heath care for frail elderly people living in different settings and to explore opinions of dentists towards new concepts in developing a community approach.

Method:  Data were collected from a sample of 101 dentists (15%) in the county of Antwerp using a self‐administered 30‐item questionnaire including questions about age, gender, education, organisational aspects of dental surgery, questions concerning dentists’ own contribution to oral healthcare services for frail elderly people and statements concerning opinions and attitude toward the organisation of oral health care for frail elderly people. At the same time, qualitative data were collected from focus group sessions with all participating dentists. Non‐parametric analysis was used to explore possible relationships between opinion and possible explanatory variables.

Results:  Half of the dentists offered dental services to residential or nursing homes (mean number of treatments a year: 5.4) and at home (mean number of treatments a year: 2.4). Prosthetic treatments such as relieving denture pressure points, repairing, rebasing and making new dentures were carried out in 77.4% and 76.7% of the cases in residential or nursing homes and at home respectively. Extractions were carried out in 16% and 18.6% of the cases in both living situations respectively. The main reasons for dentists refusing domiciliary oral health care were the absence of dental equipment (63%), lack of time (19%), with 11% convincing the patients to be treated in their dental surgery. Analysis showed different opinions of dentists depending on age, gender and university of education; however, statistically significant differences were only found by age.

Conclusion:  The older the dentist, the greater the tendency to refuse domiciliary oral healthcare services. The younger dentists were reluctant to cooperate in the provision of oral health care in a structured community approach.
Bonding acrylic teeth to acrylic resin denture bases: a review
Authors: Patil S. B. , Naveen B. H. , Patil N. P.
Published: August 2006

Partial or complete dentures are more commonly constructed for the elderly group of the population. Teeth debonding from the dentures can be frustrating to the patients as well as the dentist. Research has been carried out and is continuing to study the issue of bonding acrylic teeth to the denture base resin. The present review takes into account the majority of research papers published in the last five decades for determining the bond strength. Selection of more compatible combinations of denture base resins and acrylic teeth may reduce the number of prosthesis fractures and the resultant repairs.
The carriage of Candida species on the dorsal surface of the tongue: the correlation with the dental, periodontal and prosthetic status in elderly subjects
Authors: Wang Jing , Ohshima Tomoko , Yasunari Utako , Namikoshi Satoko , Yoshihara Akihiro , Miyazaki Hideo , Maeda Nobuko
Published: August 2006

Objectives:  To screen the carriage status of Candida species, especially Candida albicans and its genotype in an epidemiological survey and to investigate its correlation with the dental, periodontal and prosthetic status of healthy elderly subjects.

Materials and methods:  Microbiological samples were collected from the dorsum of the tongue of 366 subjects, aged 75, and cultured on CHROMagar medium. The carriage status of Candida spp. and the distribution of C. albicans genotypes by a polymerase chain reaction (PCR) method were analysed and compared with the dental, periodontal and prosthetic status of the subjects.

Results:  A high carriage rate (68.6%) of Candida spp. and the predominant species of C. albicans (72.1%) were found in this study. The prevalence, density and multi‐species of Candida spp. were significantly related to the presence of a dental prosthesis. In C. albicans, genotype A predominated (56.4%) and genotype D showed a higher prevalence (12.5%) than previous reports. When comparing Candida spp. carriage with the oral status, significant positive correlations were found with the presence of any dental prosthesis, missing teeth, the number of retained roots and the percentage of sites showing bleeding on probing (BOP), while significant negative correlations were found with the number of teeth present, sound and filled teeth.

Conclusions:  Candida carriage on the dorsum of the tongue in healthy elderly is significantly associated with the dental, periodontal and prosthetic status, especially the presence of a dental prosthesis. As the complexity of the prosthesis being worn increased, the relative risk of Candida carriage and the numbers and multi‐species of Candida increased accordingly.
In vivo Pharmacological Disease Models for Psoriasis and Atopic Dermatitis in Drug Discovery*
Authors: Petersen Thomas K.
Published: August 2006

Abstract: In order to perform relevant in vivo pharmacological investigations in drug discovery within dermatology it is fundamental to master or have access to relevant skin disease models that makes it possible to identify and validate targets and to screen and discover drugs in vivo. There is a strong need for highly predictive in vivo models in order to introduce the right drug candidates into the clinical phases of development. Recent advances in dermatological in vivo pharmacological disease models for psoriasis and atopic dermatitis are reviewed together with a discussion of the rationale for their application in drug discovery.
Interactions of Serum Albumin, Valproic Acid and Carbamazepine with the Pharmacokinetics of Phenytoin in Cancer Patients
Authors: Joerger Markus , Huitema A. D. R. , Boogerd W. , Van Der Sande J. J. , Schellens J. H. M. , Beijnen J. H.
Published: August 2006

Abstract: Phenytoin dosing is critical in cancer patients as to decreased absorption secondary to chemotherapy‐induced gastrointestinal toxicity, increased phenytoin metabolism in the liver secondary to chemotherapy, extreme patient profile that falls outside the predicted pharmacokinetic population, frequent hypoalbuminaemia and polydrug treatment. A retrospective study to assess the variability of free phenytoin and the free fraction of phenytoin, as well as the influence of comedication on these parameters was performed in cancer patients by using a population approach. Two hundred fifty‐eight data pairs of total phenytoin and free phenytoin were analysed from 155 cancer patients on stable phenytoin using non‐linear mixed‐effect modeling (NONMEM). Total and free phenytoin were determined using a fluorescence polarization immunoassay. An extensive model building procedure was subsequently used for covariate testing on the free fraction of phenytoin. Mean total phenytoin concentration was 11.7 mg/l, free phenytoin 1.25 mg/l and phenytoin free fraction 0.107. Free phenytoin was <1 mg/l on 132 occasions (51.2%) and >2 mg/l on 37 occasions (14.3%). Total and free phenytoin were significantly correlated (rS=0.827, P<0.01). The free fraction of phenytoin was independent of time after drug intake. Serum albumin concentrations and comedication with valproic acid or carbamazepine were identified by NONMEM as significant determinants of phenytoin free fraction. Co‐medication with valproic acid and carbamazepine led to a 52.5% and 38.5% increase of the free fraction of phenytoin, respectively, and a 10 g/l decrease of serum albumin to a 15.1% increase of the free fraction of phenytoin. Phenytoin pharmacokinetics could reliably be estimated from oral doses and steady‐state concentrations of protein‐bound and free phenytoin. The variability in the free fraction of phenytoin could partly be explained by the influence of albumin concentrations and antiepileptic comedication. Significant alterations of the free fraction of phenytoin and free phenytoin by co‐administration of valproic acid or carbamazepine suggest therapeutic drug monitoring of free phenytoin to be of potential benefit in cancer patients.
Isolation, Partial Purification and Characterization of Active Polypeptide from the Sea Anemone Bartholomea annulata
Authors: Sánchez‐Rodríguez Judith , Zugasti Alejandro , Santamaría Abel , Galván‐Arzate Sonia , Segura‐Puertas Lourdes
Published: August 2006

Abstract: In the sea anemone Bartholomea annulata, four different types of cnidocysts, basitrichous isorhizas, microbasic p‐mastigophores, microbasic amastigophores and spirocysts were identified. In relation to the efficacy of different substances to induce discharge of nematocysts we observe that distilled water induced more than 70% of microbasic p‐mastigophores to discharge, whereas spirocysts were discharged in a lesser extent (≈20%). The median lethal dose (LD50) in mice was found after injection of 700.7 mg protein per kg of body weight from the crude extract. The protein with neurotoxic effect was isolated using low‐pressure liquid chromatography. The neurotoxic activity was determined using sea crabs (Ocypode quadrata), injecting 15 μg of crude extract or isolated fraction into the third walking leg, and violent motor activity followed by progressive loss of sensibility to external stimuli, further leading to full paralysis were observed. The active fraction (called V) eluted at 43.9 min.
Different Patterns of Spinal Cyclooxygenase‐1 and Cyclooxygenase‐2 mRNA Expression in Inflammatory and Postoperative Pain
Authors: Prochazkova Michaela , Dolezal Tomas , Sliva Jiri , Krsiak Miloslav
Published: August 2006

Abstract:Levels of cyclooxygenase‐2 (COX‐2) mRNA, but not those of COX‐1, were reported to be raised significantly after peripheral inflammation in the rat spinal cord. The aim of the present study was to ascertain whether this pattern of COX‐2 and COX‐1 expression applies also to other pain conditions induced by surgical procedure. Experiments were performed on two types of pain models. In a model of postoperative pain, 1 cm longitudinal incision was made through skin, fascia and muscle of the plantar aspect of the right hind paw in anaesthetized rats. In the second model, peripheral inflammation was induced by unilateral, intraplantar injection of carrageenan in the right hind paw. Carrageenan injection or skin incision produced marked and significant reduction of paw withdrawal latencies to noxious radiant heat stimuli after 2 and 6 hr. Under the acute inflammation 2 and 6 hr after carrageenan injection levels of COX‐2 mRNA were markedly raised (7.8 and 15.5 times; P<0,001, respectively) while spinal levels of COX‐1 mRNA were not significantly altered (n.s.). In contrast, spinal levels of COX‐2 mRNA were raised less markedly in a model of postoperative pain (4.9 times at 2 hr; P<0,001 and 2.9 times (n.s.) at 6 hr after surgery) whilst levels of COX‐1 mRNA in the lumbar spine were increased significantly (2.3 times; P<0,001) 6 hr after surgery. The present findings indicate that expression of COX‐2 mRNA in the spine is less dominant in postoperative pain than in inflammatory pain and that spinal COX‐1 mRNA is upregulated in postoperative pain.
Heroin‐Administered Mice Involved in Oxidative Stress and Exogenous Antioxidant‐Alleviated Withdrawal Syndrome
Authors: Xu Bo , Wang Zhenhua , Li Gang , Li Bingjun , Lin Hong , Zheng Rongliang , Zheng Qiusheng
Published: August 2006

Abstract: Heroin has been shown to elevate dopamine (DA) level. It is well known that an increase in DA oxidative metabolism leads to increased reactive oxygen species (ROS) formation, and thus, ROS have been frequently associated with neuronal cell death due to damage to carbohydrates, amino acids, phospholipids, and nucleic acids. This study investigated whether there are oxidative stress and effects of exogenous antioxidants in heroin‐administered mice. The heroin‐dependent mice model was made via intraperitoneal injection. Oxidative damage of DNA, protein, and lipid was measured by analysis of single cell electrophoresis, the 2,4‐dinitrophenylhydrazine method, and thiobarbituric acid method respectively. The activities of antioxidative enzymes and total antioxidant capacity were assayed by spectrophotometry. After administration with heroin, the mice not only showed decrease of total antioxidant capacity in serum and antioxidant enzymes such as superoxide dismutase, catalase, and glutathione (GSH) peroxidase in brain, but also exhibited the oxidative damages of DNA, protein and lipid. On the other hand, exogenous antioxidants could restrain the oxidative stress, even alleviate withdrawal syndrome in heroin‐administered mice. Our results also imply a possibility that ROS may participate in the whole process of dependence and withdrawal of heroin. Therefore, strategies of blocking oxidative stress may be useful in the development of therapy for opiate abuse.
The Molecular Mechanism of Resistance to Methotrexate in Mouse Methotrexate‐Resistant Cells by Cancer Drug Resistance and Metabolism SuperArray
Authors: Zhang Chun‐yu , Feng Yuan‐xi , Yu Yang , Sun Wen‐jing , Bai Jing , Chen Feng , Fu Song‐bin
Published: August 2006

Abstract: Drug resistance is often a limiting factor in successful chemotherapy. Understanding of the molecular mechanism of resistance to methotrexate is important for optimal use as well as for the development of new drugs. Using standard cytogenetic techniques, double minutes (DMs) were detected in mouse methotrexate‐resistant cell lines inducted in vitro in this study. Moreover, functional SuperArray, determining the regulation of gene expression corresponding to 96 genes involved in the metabolism of and the development of resistance to cancer drugs was used to study in detail the molecular mechanism of resistance to methotrexate. Significant higher expressions of many genes especially dhfr, mrp5, atm and p53 were detected in methotrexate‐resistant cells than in normal mouse cells by SuperArray analysis and corresponding excessive expressions of DHFR, MRP5, ATM, and P53 proteins in methotrexate‐resistant cells were also confirmed by Western blot analysis. The results in this study indicated that DHFR, MRP5, ATM, and P53 could play important roles in resistance to methotrexate and some of them would be new potential drug targets.
Effect of Fluvoxamine and Erythromycin on the Pharmacokinetics of Oral Lidocaine
Authors: Isohanni Mika H. , Neuvonen Pertti J. , Olkkola Klaus T.
Published: August 2006

Abstract:Lidocaine is metabolized by cytochrome P450 3A4 (CYP3A4) and CYP1A2 enzymes, but inhibitors of CYP3A4 have had only a minor effect on its pharmacokinetics. We studied the effect of co‐administration of fluvoxamine (CYP1A2 inhibitor) and erythromycin (CYP3A4 inhibitor) on the pharmacokinetics of lidocaine in a double‐blind, randomized, three‐way cross‐over study. Eight healthy volunteers ingested daily either 100 mg fluvoxamine and placebo, 100 mg fluvoxamine and 1500 mg erythromycin, or their corresponding placebos (control) for five days. On day 6, 1 mg/kg lidocaine was administered orally. Plasma concentrations of lidocaine, monoethylglycinexylidide (MEGX) and 3‐hydroxylidocaine (3‐OH‐lidocaine) were measured for 10 hr. During the fluvoxamine phase the area under the plasma concentration‐time curve (AUC) and peak concentration (Cmax) of oral lidocaine were 305% (P<0.001) and 220% (P<0.05) of the control values. During the combination of fluvoxamine and erythromycin, lidocaine AUC was 360% (P<0.001) and Cmax250% (P<0.05) of those during placebo. Fluvoxamine alone had no statistically significant effect on the half‐life of lidocaine (t1/2), but during the combination phase t1/2(3.8 hr) was significantly longer than during the placebo phase (2.4 hr; P<0.01). Fluvoxamine alone and in the combination with erythromycin decreased MEGX peak concentrations by approximately 50% (P<0.001) and 30% (P<0.01), respectively. We conclude that inhibition of CYP1A2 by fluvoxamine considerably reduces the presystemic metabolism of oral lidocaine and may increase the risk of lidocaine toxicity if lidocaine is ingested. The concomitant use of both fluvoxamine and a CYP3A4 inhibitor like erythromycin may further increase plasma lidocaine concentrations.
Systemic effects of angiotensin III in conscious dogs during acute double blockade of the renin–angiotensin–aldosterone‐system
Authors: Gammelgaard I. , Wamberg S. , Bie P.
Published: August 2006

Aims:  The study was designed to determine (i) whether the effects of angiotensin III (AngIII) are similar to those of angiotensin II (AngII) at identical plasma concentrations and (ii) whether AngIII operates solely through AT1‐ receptors.

Methods:  Angiotensin II (3 pmol kg−1 min−1–3.1 ng kg−1 min−1) or AngIII (15 pmol kg−1 min−1–14 ng kg−1 min−1) was infused i.v. during acute inhibition of angiotensin converting enzyme (enalaprilate; 2 mg kg−1) and of aldosterone (canrenoate; 6 mg kg−1 plus 1 mg kg−1 h−1). Arterial plasma concentrations of angiotensins were determined by radioimmunoassay using a cross‐reacting antibody to AngII. During ongoing peptide infusion, candesartan (2 mg kg−1) was administered to block the AT1‐receptors.

Results:  Angiotensin immunoactivity in plasma increased to 60 ± 10 pg mL−1 during infusion of AngII or infusion of AngIII. AngII significantly increased mean arterial blood pressure (+14 ± 4 mmHg) and plasma aldosterone by 79% (+149 ± 17 pg mL−1) and reduced plasma renin activity and sodium excretion (−41 ± 16 mIU L−1 and −46 ± 6 μmol min−1 respectively). AngIII mimicked these effects and the magnitude of AngIII responses was statistically indistinguishable from those of AngII. All measured effects of both peptides were blocked by candesartan.

Conclusion:  At the present arterial plasma concentrations, AngIII is equipotent to AngII with regard to effects on blood pressure, aldosterone secretion and renal functions, and these AngIII effects are mediated through AT1‐ receptors. The metabolic clearance rate of AngIII is five times that of AngII.
Mediators of tubuloglomerular feedback regulation of glomerular filtration: ATP and adenosine
Authors: Castrop H.
Published: August 2006

In the juxtaglomerular apparatus of the kidney the loop of Henle gets into close contact to its parent glomerulus. This anatomical link between the tubular system and the vasculature of the afferent and efferent arteriole enables specialized tubular cells, the macula densa (MD) cells, to establish an intra‐nephron feedback loop designed to control preglomerular resistance and thereby single nephron glomerular filtration rate. This review focuses on the signalling mechanisms which link salt‐sensing MD cells and the regulation of preglomerular resistance, a feedback loop known as tubuloglomerular feedback (TGF). Two purinergic molecules, ATP and adenosine, have emerged over the years as most likely candidates to serve as mediators of TGF. Data will be reviewed supporting a role of either ATP or adenosine as mediators of TGF. In addition, a concept will be discussed that integrates both ATP and adenosine into one signalling cascade that includes (i) release of ATP from MD cells upon increases in tubular salt concentration, (ii) extracellular degradation of ATP to form adenosine, and (iii) adenosine‐mediated vasoconstriction of the afferent arteriole.
Apparent Digestibility Coefficients of Selected Feed Ingredients for Yellowfin Seabream, Sparus latus
Authors: Wu Xiao‐Yi , Liu Yong‐Jian , Tian Li‐Xia , Mai Kang‐Sen , Yang Hui‐Jun
Published: August 2006

The apparent digestibility coefficients (ADC) of dry matter (DM), crude protein (CP), gross energy (GE), and amino acid in seven feed ingredients were determined with juvenile yellowfin seabream (initial body weight, 41 ± 2 g; means ± SD) through two digestibility trials. The ingredients consisted of white fish meal (WFM), Peruvian fish meal (PFM), brown fish meal (BFM), rapeseed meal (RM), soybean meal (SBM), extruded soybean meal (extruded SBM), and peanut meal (PM). In each of the two trials, a casein–gelatin reference diet was mixed with test ingredients in a ratio of 70:30 to produce a series of diets, and yttrium oxide was used as the inert marker. The reference and test diets were fed to yellowfin seabream reared at 27.5 ± 1 C, and fecal samples were collected by siphoning. The derived DM, CP, and GE ADCs (means ± SD) for the test ingredients were, respectively, WFM – 72.3 ± 3.87, 86.4 ± 1.06, and 93.6 ± 2.63; PFM – 54.1 ± 15.45, 80.5 ± 7.81, and 77.4 ± 11.9; BFM – 57.7 ± 2.34, 82.8 ± 3.07, and 84.5 ± 5.77; RM – 33.5 ± 5.50, 84.7 ± 2.83, and 56.3 ± 9.87; SBM – 58.7 ± 4.42, 92.6 ± 3.94, and 58.1 ± 2.91; extruded SBM – 65.1 ± 16.52, 89.7 ± 1.68, and 64.8 ± 6.23; and PM – 70.6 ± 1.43, 97.3 ± 3.52, and 59.8 ± 4.78. The ADC of CP of both plant and animal feed ingredients was high, whereas DM and GE values varied greatly. Apparent DM digestibility coefficients of ingredients decreased as ash or fiber contents of ingredients increased, and the variation of apparent GE digestibility coefficients of ingredients is similar to that in DM, with the exception of the value for PM.
Effect of Photoperiod Manipulation on Broodstock Spawning, Fertilization Success, and Egg Developmental Abnormalities in Atlantic Cod, Gadus morhua
Authors: Penney Randy W. , Lush Pauline L. , Wade A. Joy , Brown Joseph A. , Burton Margaret P. M.
Published: August 2006

Spawning activity in two captive Atlantic cod broodstock groups previously captured from the wild stock fishery was monitored over three spawning seasons. Both groups spawned under ambient photoperiod (PP) in the first year, after which photomanipulation was applied to compress the PP cycle of one broodstock group, while the second group was maintained on natural PP. Increased total egg volumes, number of egg batches, total egg production, and duration of the spawning season were observed in both ambient PP and advanced PP groups in the second and third spawning seasons. Compared to ambient controls, the photoadvanced group commenced spawning earlier, had a longer spawning season, produced a lower total volume of eggs over the entire spawning season, and had lower mean daily batch volumes of eggs, and the eggs were of smaller mean diameter. Fertilization success was >90% in all years, increased in both groups in the first year after photomanipulation but declined to prior levels in the following year. No consistent difference in fertilization success was observed between advanced PP and ambient PP groups. Rates of cell development abnormalities were low (<10%) in both groups over the three spawning seasons. Abnormalities of cell symmetry and clarity increased in both ambient PP and advanced PP groups over the three spawning seasons. However, no consistent differences in rate of cell abnormalities were observed between advanced PP and ambient PP groups within years. We conclude that PP advancement is an effective technique to compress the time between successive spawning periods in Atlantic cod and does not negatively affect fertilization success or rates of cell developmental abnormalities. However, it has a negative effect on both volume and size of eggs produced.
Effects of Tank Wall Color and Up‐welling Water Flow on Growth and Survival of Eurasian Perch Larvae (Perca fluviatilis)
Authors: Jentoft Sissel , ØXnevad Sigurd , Aastveit Are H. , Andersen ØIvind
Published: August 2006

The influence of tank wall color and up‐welling water flow on growth and survival of Eurasian perch larvae (Perca fluviatilis) was tested in an intensive culture system. Newly hatched larvae were fedArtemianauplii, later combined with dry feed, and reared for 5 wk in either black tanks with up‐welling water flow or in gray tanks with or without up‐welling water flow. The perch larvae grew significantly faster in black tanks than in gray tanks regardless of water flow. Two weeks after hatching, a significantly higher mean weight was shown in larvae reared in black tanks compared to larvae reared in gray tanks with up‐welling water flow, and after 4 wk, the mean weight was significantly higher than in both of the other treatments. The difference in growth was further enhanced during the last week of the experiment, and the final mean weights were 51.1 ± 1.9 mg in black tanks with up‐welling water flow, 23.8 ± 2.1 mg in gray tanks with up‐welling water flow, and 23.7 ± 2.2 mg in gray tanks without up‐welling water flow. The cumulative mortality at the end of the experiment averaged 75% in all treatment groups. Taken together, the enhanced growth of Eurasian perch larvae in black tanks could be explained by high prey contrast and increased prey consumption. Up‐welling water flow had no impact on growth and survival of the perch larvae in gray tanks, indicating that the availability and consumption of the prey were independent of water movement.
A Zonal Model for Large Enclosures With Combined Stratification Cooling and Natural Ventilation: Part 1—Model Generation and its Procedure
Authors: Gao Jun , Zhao Jia-ning , Li Xiao-dong , Gao Fu-sheng
Published: August 2006

This paper describes a combined system of stratificated air conditioning and natural ventilation for large enclosures, which uses stratificated air conditioning to cool the occupied part of a space and uses natural ventilation to cool the upper part to reduce heat penetration into the lower air-conditioned part. A zonal model is constructed to predict the vertical temperature profiles of large enclosures under such a combined system. This model incorporates airflow and heat transfer throughout the space into the mass and heat balance equations for each horizontally settled zone. It introduces some particular flow dynamics and thermal effects into the predictions of mean airflows and temperature distributions. Different from those pressure-based zonal models applied generally to the predictions for small building rooms, it is termed a temperature-based zonal model, which uses correlations based on temperature differences in combination with submodels for modeling of mass flow and heat transfer in the large enclosures. The present paper provides a calculation procedure for the model. Model performances are then discussed through analyzing the impacts of some influential factors on the space air temperature profiles.
LAHU Heat Recovery System Optimal Operation and Control Schedules
Authors: Cui Yujie , Liu Mingsheng
Published: August 2006

Optimal operation and control of heat recovery in an integrated Laboratory Air Handling Unit (LAHU) system differs substantially from that in conventional dedicated AHUs for laboratory buildings with a 100% outside air AHU for laboratory spaces, since the LAHU allows economizer operation for both offices and laboratories. Optimal operation and control schedules of the heat recovery systems in the LAHU have been developed to minimize the total thermal energy cost. This paper presents the procedure, methodology, and results of generic optimal heat recovery control schedules for the LAHU and investigates its impact on the LAHU potential thermal and pump energy savings. The optimal control schedule can potentially save 14% to 27% thermal energy and 17% to 100% pump energy during the winter under weather conditions that prevail in Omaha, Nebraska. The findings discussed in this paper also apply to any heat recovery system, where AHU has an economizer function.
Impacts of Balancing Valves on Pump Energy and Control Performance in Variable Water Flow Systems
Authors: Zheng B. , Liu M.
Published: August 2006

There is no common agreement on the use of balance valves in the most popular variable water flow systems. A comprehensive theoretical analysis has been conducted to investigate the impacts of balance valves on initial cost, pump operation power, and system control performance. The investigation finds that eliminating balance valves can (i) reduce by 20–40% pump energy consumption in a typical variable flow water system, (ii) reduce the maximum pressure drop across control valves, and (iii) improve pump efficiency at most partial load conditions. The reduced pressure drops across control valves improve system control performance and may allow selecting some control valves at lower close-off pressures. Consequently, eliminating balancing valves can also potentially reduce system initial cost.
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Catalyzed SiC-Foam Absorber for Solar Reforming Receiver-Reactor
Authors: Kodama Tatsuya , Moriyama Takuya , Shimoyama Takehiro , Gokon Nobuyuki , Andou Hidemasa , Satou Nobuhiro
Published: August 2006

High-temperature solar reforming of methane with CO2 is investigated using a directly solar-irradiated absorber subjected to a solar mean flux level above 400kWm−2 (the peak flux of about 700kWm−2). The new type of catalytically activated ceramic foam absorber—a Ru∕Ni-Mg-O catalyzed SiC-foam absorber—was prepared, and its activity was tested in a laboratory-scale volumetric receiver-reactor with a transparent (quartz) window by using a sun-simulator. Compared to conventional Rh∕Al2O3 catalyzed SiC-foam absorber, this new catalytic absorber is more cost effective and is found to exhibit a superior reaction performance at the high solar flux or at high temperatures, especially above 950°C. This new absorber will be applied in solar receiver-reactor systems for converting concentrated high solar fluxes to chemical fuels via endothermic natural-gas reforming at high temperatures.
A Linear Stability Study of the Gradient Zone of a Solar Pond
Authors: Rebaï L. Kaffel , Mojtabi A. K. , Safi M. J. , Mohamad A. A.
Published: August 2006

The linear stability of a plane layer with horizontal temperature and concentration stratification corresponding to gradient zone of a solar pond is investigated. The problem is described by Navier-Stokes equations with Boussinesq-Oberbeck approximation. Two source terms are introduced in the energy equations: the absorption of solar energy characterized by the extinction radiative coefficient μe and by the parameter f defined as the ratio of extracted heat flux to absorbed heat flux in the lower convective zone. The influence of the parameters μe and f on the onset of thermosolutal convection in the case of confined and infinite layers is analyzed. It is found that convection starts in an oscillatory state, independently of the RaS value. Different convection solutions were found for marginal stability and steady state.
Dual Receiver Concept for Solar Towers up to 100 MW
Authors: Eck M. , Buck R. , Wittmann M.
Published: August 2006

The dual receiver concept presented in this paper improves the adaptation of the central receiver to the steam cycle in a solar thermal power plant. By combination of an open volumetric air heater and a tubular evaporator the dual receiver concept profits from the advantages of these two concepts while their characteristic problems are avoided. The water is evaporated directly in the tubular steam generator; preheating and superheating are done in heat exchangers by using the hot air from the volumetric receiver. This paper presents a concept study that extends previous work on the 10MWel level (Buck et al., 2004, “Dual Receiver Concept for Solar Towers,” Proc. 12th Solar PACES Int. Symposium, Oct. 6–8, Oaxaca, Mexico) to a level of 100MWel, which is the expected power range of future plants. The results confirm the benefits of the new concept, resulting from higher thermal efficiency of the receiver and lower parasitic power consumption. The annual mean efficiency is increased from 13% to 16%. Advantageous are also the reduced thermal loads in the receiver components.
Analysis of Sandwich Panels for an Energy Efficient and Self-Supporting Residential Roof
Authors: Thomas Daniel , Mantell Susan C. , Davidson Jane H. , Goldberg Louise F. , Carmody John
Published: August 2006

The structural and thermal feasibility of a self-supporting sandwich panel for energy efficient residential roof applications is assessed. The assessment is limited to symmetric sandwich panels comprising two face sheets and an insulating core. Feasible panel designs are presented for loading conditions, corresponding to southern and northern climates in the United States. The base case panel is 5.5m long for a nominal 4.6m horizontal span and an 8∕12 roof pitch. Face sheet materials considered are oriented strand board, steel, and fiber reinforced plastic. Core materials considered are expanded polystyrene, extruded polystyrene, polyurethane, and poly(vinyl-chloride) foams. A wide range of material options meet building code limits on deflection and weight and prevent face sheet fracture and buckling, and core shear failure. Panels are identified that have structural depths similar to conventional wood rafter construction. Shortening the overall panel length provides greater choice in the use of materials and decreases the required panel thickness. Suggestions for improved panel designs address uncertainty in the ability of the plastic core to withstand long term loading over the expected life of residential buildings.
Multiple Air-Jet Window Cooling for High-Temperature Pressurized Volumetric Receivers: Testing, Evaluation, and Modeling
Authors: Röger M. , Pfänder M. , Buck R.
Published: August 2006

High air outlet temperatures increase the solar share of pressurized solar receivers for gas turbines, operated in solar-fossil hybrid mode. However, an increase in outlet temperature over 800°C leads to excessive heating of the receiver window, unless it is actively cooled. This paper describes modeling, testing, and evaluation of a high-temperature receiver with external multiple air-jet window cooling. An asymmetric window-cooling design with pulsating air mass flow rates achieves suitable cooling of the concave fused-silica window. A thermodynamic receiver model, comprising nongray radiative heat transfer, convection, and conduction is the basis of the external window cooling design. In addition to high-temperature testing with window cooling in operation, solar tests at lower temperatures with no window cooling were conducted to verify the thermodynamic receiver model. Temperature distributions on the quartz window and the absorber were determined by an infrared scanner which was specially developed for temperature measurement on the high-temperature module. Comparisons of simulations and measurements show good agreement. With multiple air-jet window cooling, receiver air outlet temperatures over 1000°C could be reached, while window temperatures are kept below 800°C.
A Novel Solar-Hybrid Gas Turbine Combined Cycle With Inherent CO2 Separation Using Chemical-Looping Combustion by Solar Heat Source
Authors: Hong Hui , Jin Hongguang , Liu Baiqian
Published: August 2006

In this paper we propose a novel CO2-recovering hybrid solar-fossil combined cycle with the integration of methane-fueled chemical-looping combustion, and investigate the system with the aid of the Energy-Utilization Diagram (EUD). Chemical-looping combustion (CLC) consists of two successive reactions: first, methane fuel is oxidized by metal oxide(NiO)as an oxygen carrier (reduction of metal oxide); and second, the reduced metal (Ni) is successively oxidized by combustion air (the oxidation of metal). The oxidation of methane with NiO requires a relative low-grade thermal energy at 300°C-500°C. Then concentrated solar thermal energy at approximately 450°C-550°C can be utilized to provide the process heat for this reaction. By coupling solar thermal energy with methane-fueled chemical-looping combustion, the energy level of solar thermal energy at around 450°C-550°C can be upgraded to the chemical energy of solid fuel Ni for better utilization of solar energy to generate electricity. The synergistic integration of solar thermal energy and chemical-looping combustion could make the exergy efficiency and the net solar-to-electric efficiency of the solar hybrid system more than 60% and 30%, respectively, at a turbine inlet temperature (TIT) of 1200°C. At the same time, this new system has an extremely important advantage of directly suppressing the environmental impact due to lack of energy penalty for CO2 recovery. Approximately 9–15 percentage points higher efficiency can be achieved compared to the conventional natural gas-fired combined cycle with CO2 separation. The results obtained here are promising and indicate that this novel solar hybrid combined cycle offers the new possibility of CO2 mitigation using both green energy and fossil fuels. These results also provide a new approach for highly efficient use of solar thermal energy to generate electricity.
Two distinct fungi colonize roots and rhizomes of the myco-heterotrophic Afrothismia gesnerioides (Burmanniaceae)
Authors: Imhof Stephan
Published: August 2006

The subterranean organs of Afrothismia gesnerioides H. Maas consist of short rhizomes densely covered with ovoid root tubercles, each of which may extend into a short filiform root extension. Serial sections revealed the presence of two distinct fungi occupying different niches within the plant tissues. Rhizomes and roots are divided into separate compartments hosting different morphotypes of the aseptate, exclusively intracellular hyphae of fungus A: (i) straight and persistent hyphae in the root epidermis, root extension, and outer rhizome cortex, (ii) coiled but still persistent hyphae in the third root layer, (iii) coiled hyphae undergoing degeneration in the root cortical parenchyma, (iv) starch depositions in the inner rhizome cortex and no colonization by fungus A, and (v) a partly collapsed root hypodermis serving as compartment barrier. The colonization by fungus A is interpreted as an aberrant arbuscular mycorrhiza of the Paris type. The compartmentation allows the separation of tissues where the hyphae stay functional from those in which the fungal material is digested. This pattern may represent a complex but efficient strategy for a sustained benefit from the few fungal penetrations that occur. Comparison with earlier work on Afrothismia winkleri (Engl.) Schltr. revealed considerable differences between the mycorrhizae that are interpreted as evolutionary steps. There are signs that these changes even may have improved the mycorrhizal benefit for the plant. The monomorphic hyphae of fungus B are smaller in diameter, septate, grow inter- as well as intra-cellularly, but are always characteristically appressed to the inner cell walls. It does not change its appearance within the root/rhizome compartments as does fungus A. Neither hyphal degeneration nor interferences with fungus A, starch depositions, or alterations in the development of A. gesnerioides could be noticed. Fungus B possibly is a commensal, but relevance to the symbiosis cannot be ruled out.
An assessment of genetic diversity in Desmodium sumichrastii (Fabaceae) of central Mexico
Authors: Bedolla-Garcia Brenda Y. , Lara-Cabrera Sabina I.
Published: August 2006

The genus Desmodium contains ca. 450 species, distributed in Eastern Asia, Mexico, and Brazil, with 40 endemic species in Mexico, including Desmodium sumichrastii (Schinder) Standley. Randomly amplified polymorphic DNA (RAPD) variation was used to assess genetic variation within and among five populations of D. sumichrastii from west-central Mexico, constituting the first assessment in the tribe Desmodieae. Ninety percent of all bands were polymorphic for the 10 decamer RAPD primers used. Sixty-one percent of the variation was within populations, and 39% was among them. This pattern of higher variation within than among populations is unusual, but can be attributed to ethological characteristics of pollinators. The unweighted pair-group method with arithmetic averages (UPGMA) dendrogram based on Nei's genetic distances plots populations from Jalisco together, whereas populations from Aguililla in the neighboring state of Michoacan are separated and next to the San Miguel del Monte population (also in Michoacan). However, the dendrogram based on Dice's similarity coefficient calculated for all individuals separately groups the populations from Aguililla. We also found a significant correlation between genetic and geographic distances, which is in agreement with Dice's UPGMA dendrogram, where closer populations are more genetically similar. Interestingly the most diverse populations are located within a Biosphere Preserve, and the least diverse populations are located in heavily disturbed sites.
Composition and function of biological soil crust communities along topographic gradients in grasslands of central interior British Columbia (Chilcotin) and southwestern Yukon (Kluane)
Authors: Marsh Janet , Nouvet Sabine , Sanborn Paul , Coxson Darwyn
Published: August 2006

Grasslands in the rainshadow of the Chilcotin (British Columbia) and St. Elias (Kluane, Yukon) mountain ranges of western Canada are characterized by widely spaced clumps of bunchgrass and sage, between which can be found lichen-dominated biological soil crusts (BSC). Our examination of Chilcotin and Kluane grasslands showed differential BSC development along topographic gradients, favoring those sites with lower levels of soil disturbance. Lichen species richness was greatest in upper topographic positions, that is, on valley side terraces in the Chilcotin and esker slopes in Kluane. Common BSC lichens in both grasslands included Acarospora schleicheri, Caloplaca tominii , Collema tenax , Diploschistes muscorum , Fulgensia bracteata , Phaeorrhiza nimbosa , Placidium squamulosum , and Psora decipiens . Chilcotin BSC additionally contained many Cladonia species (e.g., C. carneola , C. chlorophaea , C. pyxidata ), particularly where vegetation had encroached on BSC. The potential for nitrogen fixation by Collema -dominated crusts in Kluane was examined using acetylene reduction assays (ARA) and soil surface microclimate monitoring. ARA activity was highly dependent upon the duration of wetting events, reaching C2H4 levels up to 63 μmol·m–2·h–1after 40 h of hydration. Given the abundance of Collema-dominated crusts in Kluane and the optimal conditions for ARA activity that are reached during wetting–drying transitions, we hypothesized that BSC communities potentially make an important contribution to ecosystem nitrogen budgets. Enrichment in total and mineralizable N, as well as 15N natural abundance values, was consistent with N fixation making an important contribution to soil N pools in these ecosystems. Both Chilcotin and Kluane BSC had similar spongy microstructures that contrasted with the platy microstructures of the underlying surface mineral soils, but only the latter site showed micromorphological evidence of burial of mosses and other BSC components by continuing loess deposition. BSC may have performed similar roles in analogous steppe-like ecosystems that existed under full-glacial conditions in the unglaciated areas of eastern Beringia in Alaska and Yukon.
Structural characterization of the stigma-style complex of Cynara cardunculus (Asteraceae) and immunolocalization of cardosins A and B during floral development
Authors: Duarte Patrícia , Figueiredo Raquel , Pereira Susana , Pissarra José
Published: August 2006

Studies were carried out on the structure of the stigma and style of Cynara cardunculus L. (cardoon) during flower development. The stigma is of the dry type with a papillate cuticularized epidermis. During development, the unicellular papillae become match-stick shaped, cuticularize, and show an increase in vacuolar volume. In mature papillae, two morphologically different vacuoles were observed, one electron-dense and the other electron-transparent, putatively corresponding to distinct vacuolar populations. These vacuoles label differently for cardosin A, specifically detected in the electron-dense compartments. The style is solid with a cuticularized epidermis and a central core of transmitting tissue (TT) several cell layers thick. The TT cells show abundant rough endoplasmic reticulum and Golgi bodies, associated with active secretion. During maturation, TT cells become increasingly separated by a polysaccharide-rich extracellular matrix. Communication between TT cells is maintained via plasmodesmata in longitudinal walls. Distribution of cardosins A and B in developing C. cardunculus flowers was also characterized. The presence of aspartic proteinases (APs) in flowers is unusual, generally occurring at low levels. Cardosins A and B are always present in cardoon florets and localize at distinct pistil levels: stigma (papillae) and style (TT), respectively. This differential localization suggests distinct biological functions for cardosins, most likely essential for reproduction in this species.
Leptographium profanumsp.nov., a new species from hardwood roots in North America
Authors: Jacobs Karin , Eckhardt Lori G. , Wingfield Michael J.
Published: August 2006

Species of Leptographium are anamorphs of Ophiostoma and best known as associates of tree-infesting bark beetles. The majority of these fungi and their insect associates are found on conifers where they typically cause sap-stain of lumber. A small number of species are also known as tree pathogens. Relatively few Leptographium species are found on angiosperm trees. Species described from these niches have increased in recent years. The objective of this study was to characterize a Leptographium species isolated from the roots of various hardwood trees in the southeastern United States. Morphology of this fungus differed from that of other Leptographium species. Comparisons of DNA sequences for part of the ITS2–28S ribosomal DNA region, the β-tubulin, and the elongation 1-α gene regions also showed that this fungus represents an undescribed taxon. The fungus is thus described as Leptographium profanum sp.nov.