bluuebunny/crossref_metadata_2025 huggingface dataset:
Zolpidem Use and Hip Fractures in Older People
Authors: Wang Philip S. , Bohn Rhonda L. , Glynn Robert J. , Mogun Helen , Avorn Jerry
Published: February 2005

OBJECTIVES: The widespread use of sedative‐hypnotics in older populations makes it imperative to identify hazardous regimens that should be avoided and safer regimens that may be used preferentially by older people. Although benzodiazepines have been shown to increase fall and fracture risk, zolpidem, a nonbenzodiazepine hypnotic, has been advocated as a safer alternative.

DESIGN: Case‐control study of hip fracture cases and controls in 1994.

SETTING: All subjects were age 65 and older and enrolled in Medicare, and in Medicaid or the Pharmaceutical Assistance to the Aged and Disabled program of New Jersey.

PARTICIPANTS: Cases (n = 1,222) were patients who underwent surgical repair of a hip fracture. They were frequency‐matched to four controls (n = 4,888) based on age and gender.

MEASUREMENTS: Use of sedative‐hypnotics and other medications was assessed in the 180 days before the index event. We assessed other covariates, including demographic, clinical, and healthcare utilization variables in the prior 180 days.

RESULTS: Zolpidem use was associated with a significant increased risk of hip fracture (adjusted odds ratio (AOR) 1.95; 95% confidence interval (CI) = 1.09–3.51). Other psychotropic medication classes with significantly increased risks included benzodiazepines (AOR 1.46; 95% CI = 1.21–1.76), antipsychotic medications (AOR 1.61; 95% CI = 1.29–2.01), and antidepressants (AOR 1.46; 95% CI = 1.22–1.75). In subanalyses, preferential use of zolpidem by subjects at greater risk of hip fracture did not appear to explain the apparent risk of hip fracture with zolpidem use.

CONCLUSION: Use of zolpidem by older people was associated with nearly twice the risk of hip fracture, even after controlling for possible demographic and clinical confounders. Rather than being a safer alternative, zolpidem may be associated with risks that are as great as those seen with conventional benzodiazepines in older patients.
Laser Lead Extraction: Is There a Learning Curve?
Authors: GHOSH NINA , YEE RAYMOND , KLEIN GEORGE J. , QUANTZ MACKENZIE , NOVICK RICHARD J. , SKANES ALLAN C. , KRAHN ANDREW D.
Published: February 2005

Laser extraction of device leads offers an attractive alternative to countertraction and electrosurgical dissection sheath, potentially increasing efficacy and reducing complications. Wider adoption of this technology depends on relative ease of use. We report the experience of a new center to define the “learning curve.” We performed 76 laser lead extractions in 75 patients (age 63 ± 17 years, 59 male) from July 2001 to January 2004. Two experienced device implanters who were novice extractors underwent a 2‐day site visit to a high volume extraction center for training. Lead extractions were performed in the operating room with immediate surgical backup. The indication for extraction was infection in 39 (systemic in 15), erosion or pain in 11, and lead related or debulking in 25. Complete removal was achieved in 139 of 145 leads (14 ICD, 131 pacemaker). Partial removal (<4 cm retained) was achieved in five leads (4%), and one lead could not be extracted. Complete success was 95% in the first third of patients, 94% in the second third, and 100% in the latter third. Fluoroscopy time fell from 19 ± 22 minute in the first third of patients to 11 ± 8 minute in the second third to 8 ± 4 minute in the latter third (ANOVA P = 0.02). No major complications occurred. Local bleeding required minor left subclavian vein repair in two individuals. Symptomatic venous thrombosis occurred in 3 of the first 11 cases 1–21 days after extraction, but did not occur in the next 64 consecutive patients who received a 1‐month anticoagulation regimen (27% vs 0%, P < 0.001). One patient developed venous thrombosis 3 weeks following cessation of warfarin therapy. Practice guidelines reasonably recommend appropriate training prior to independent performance of lead extraction. The current study suggests that experienced device implanters with appropriate operative backup taking a limited, but intensive training program can be safe and effective at lead extraction in a short time, in part a reflection of the improved technology.
The Earliest Published Electrocardiogram Showing Ventricular Preexcitation
Authors: VON KNORRE GEORG H.
Published: February 2005

When in 1930, Wolff, Parkinson, and White published what is today known as the WPW, or preexcitation syndrome, they, and subsequently others, found few comparable cases in the preceding literature. Among these the report of Cohn and Fraser, published in 1913, was the earliest. However, another even earlier documentation in a 1909 article by Hoffmann escaped notice till now. The ECG of a patient with paroxysmal tachycardia reveals a short PR interval and a delta‐wave‐induced widening of the QRS complex, even though the reproduced tachycardia was not preexcitation related. The interpretation of this poorly reproduced ECG can be confirmed by another and more detailed description of the patient in an electrocardiography textbook published in 1914 by the same author. Thus, the earliest publication of an ECG showing ventricular preexcitation now can be dated back to 1909. Moreover, the Hoffmann monograph contains two additional examples of the WPW syndrome not noticed until now. All three cases published by Hoffmann had their first ECG recordings in 1912 or earlier.
The Presence of Epsilon Waves in a Patient with Acute Right Ventricular Infarction
Authors: ZORIO ESTHER , ARNAU MIGUEL A. , RUEDA JOAQUÍN , ALMENAR LUIS , OSA ANA , MARTÍNEZ‐DOLZ LUIS , OSCA JOAQUÍN , PALENCIA. MIGUEL A.
Published: February 2005

Epsilon wave is an unusual electrocardiographical finding, which may appear in other pathological conditions besides the arrhythmogenic right ventricular dysplasia, particularly in the acute myocardial infarction of the right ventricle, the inferior, or the posterior wall of the left ventricle. Its real incidence in these acute coronary syndromes remains unknown and will be probably difficult to assert, since it may be unnoticed by inexperienced physicians because of its little voltage. The outstanding interest of this case lies in the clear electrocardiographical images and in the step‐by‐step differential diagnosis discussed by the authors.
Mechanism‐Based Modeling of Complex Biomedical Systems
Authors: Mosekilde Erik , Sosnovtseva Olga V. , Holstein‐Rathlou Niels‐Henrik
Published: February 2005

Abstract:Mechanism‐based modeling is an approach in which the physiological, pathological and pharmacological processes of relevance to a given problem are represented as directly as possible. This approach allows us (i) to test whether assumed hypotheses are consistent with observed behaviour, (ii) to examine the sensitivity of a system to parameter variation, (iii) to learn about processes not directly amenable to experimentation, and (iv) to predict system behavior under conditions not previously experienced. The paper illustrates different aspects of the application of mechanism‐based modeling through three different examples of relevance to the treatment of diabetes and hypertension: subcutaneous absorption of insulin, pulsatile insulin secretion in normal young persons, and synchronization of the pressure and flow regulation in neighbouring nephrons. The underlying ideas are that each regulatory mechanism represents the target for intervention and that the development of new and more effective drugs must be based on a deeper understanding of the biological processes.
Regulation of activity‐dependent dendritic vasopressin release from rat supraoptic neurones
Authors: Ludwig Mike , Bull Philip M. , Tobin Vicky A. , Sabatier Nancy , Landgraf Rainer , Dayanithi Govindan , Leng Gareth
Published: February 2005

Magnocellular neurones of the hypothalamus release vasopressin and oxytocin from their dendrites and soma. Using a combination of electrophysiology, microdialysis, in vitro explants, and radioimmunoassay we assessed the involvement of intracellular Ca2+ stores in the regulation of dendritic vasopressin release. Thapsigargin and cyclopiazonic acid, which mobilize Ca2+ from intracellular stores of the endoplasmic reticulum, evoked vasopressin release from dendrites and somata of magnocellular neurones in the supraoptic nucleus. Thapsigargin also produced a dramatic potentiation of dendritic vasopressin release evoked by osmotic or high potassium stimulation. This effect is long lasting, time dependent, and specific to thapsigargin as caffeine and ryanodine had no effect. Furthermore, antidromic activation of electrical activity in the cell bodies released vasopressin from dendrites only after thapsigargin pretreatment. Thus, exposure to Ca2+ mobilizers such as thapsigargin or cyclopiazonic acid primes the releasable pool of vasopressin in the dendrites, so that release can subsequently be evoked by electrical and depolarization‐dependent activation. Vasopressin itself is effective in inducing dendritic vasopressin release, but it is ineffective in producing priming.
Visualization of localized store‐operated calcium entry in mouse astrocytes. Close proximity to the endoplasmic reticulum
Authors: Golovina Vera A.
Published: February 2005

Unloading of endoplasmic reticulum (ER) Ca2+ stores activates influx of extracellular Ca2+ through ‘store‐operated’ Ca2+ channels (SOCs) in the plasma membrane (PM) of most cells, including astrocytes. A key unresolved issue concerning SOC function is their spatial relationship to ER Ca2+ stores. Here, using high resolution imaging with the membrane‐associated Ca2+ indicator, FFP‐18, it is shown that store‐operated Ca2+ entry (SOCE) in primary cultured mouse cortical astrocytes occurs at plasma membrane–ER junctions. In the absence of extracellular Ca2+, depletion of ER Ca2+ stores using cyclopiazonic acid, an ER Ca2+‐ATPase inhibitor, and caffeine transiently increases the sub‐plasma‐membrane Ca2+ concentration ([Ca2+]SPM) within a restricted space between the plasma membrane and adjacent ER. Restoration of extracellular Ca2+ causes localized Ca2+ influx that first increases [Ca2+]SPM in the same restricted regions and then, with a delay, in ER‐free regions. Antisense knockdown of the TRPC1 gene, proposed to encode endogenous SOCs, markedly reduces SOCE measured with Fura‐2. High resolution immunocytochemistry with anti‐TRPC1 antibody reveals that these TRPC‐encoded SOCs are confined to the PM microdomains adjacent to the underlying ‘junctional’ ER. Thus, Ca2+ entry through TRPC‐encoded SOCs is closely linked, not only functionally, but also structurally, to the ER Ca2+ stores.
Aberrations in the mismatch repair genes and the clinical impact on oesophageal squamous carcinomas from a high incidence area in South Africa
Authors: Naidoo R , Ramburan A , Reddi A , Chetty R
Published: February 2005

Aims:To investigate the incidence of genetic aberrations in the DNA repair genes in a cohort of oesophageal cancers.

Methods:One hundred oesophagectomy samples of squamous cell carcinoma were studied. Normal and tumour DNA were isolated using a standard phenol/chloroform extraction procedure. Six recommended microsatellite loci with high informativity were analysed. The following markers were used: D2S123 (2p), D3S659 (3p), D3S1255 (3p), Bat 25 (4q), Bat 26 (2p), and Bat 40 (1p). The results were analysed using software attached to an automated DNA sequencer. The molecular data were then correlated with clinicopathological parameters.

Results:The incidence of microsatellite instability and loss of heterozygosity was very low. There was no significant correlation between the clinicopathological and molecular data. However, D2S123 genetic abnormalities were seen more frequently in both moderately and well differentiated tumours than in poorly differentiated tumours (p  =  0.033). Follow up data were available for only 67 of the 100 patients. Fifty patients were alive and 17 patients had died.

Conclusion:Low frequencies of genetic aberrations in these mismatch repair loci are found in squamous carcinomas of the oesophagus from a high incidence area in South Africa.
Are routine iron stains on bone marrow trephine biopsy specimens necessary?
Authors: Stuart-Smith S E , Hughes D A , Bain B J
Published: February 2005

Aims:To determine the role of Perls’ staining in bone marrow trephine biopsy sections.

Methods:The haemosiderin content of 155 Perls’ stained, formic acid decalcified trephine biopsy sections was assessed and compared with Perls’ stained aspirate samples in 105 cases and haematoxylin and eosin (H&E) stained biopsy sections in all cases.

Results:An evaluable aspirate film with positive iron or at least seven negative particles was available for 105 biopsies. Only 71 of 95 cases with detectable aspirate iron had haemosiderin detectable on a Perls’ stained section. None of 10 samples with a negative aspirate had a positive trephine biopsy. Haemosiderin was positive in 101 of the 155 Perls’ stained sections, and was detectable on the H&E stained section in 71 of these cases. In five of 54 cases with negative Perls’ staining, a small amount of haemosiderin was thought to be present on H&E staining.

Conclusions:Aspirate smears reflect bone marrow iron stores more reliably than formic acid decalcified trephine biopsy sections. The presence of iron in Perls’ stained aspirates in 44% of cases with negative Perls’ stained sections indicates that iron is often lost from sections during decalcification. However, 61% of cases with unassessable aspirate samples had a positive trephine biopsy Perls’ stain, contributing useful clinical information about iron status. Preparation of Perls’ stained sections only in cases in which aspirate samples are inadequate for iron assessment and no obvious haemosiderin is present in an H&E stained section could produce savings in staff time and reagent costs.
An immunohistochemical analysis to evaluate an inverse correlation between Runx2/Cbfa1 and NFκB in human osteosarcoma
Authors: Andela V B , Siddiqui F , Groman A , Rosier R N
Published: February 2005

Background:Dominant negative inhibition of nuclear factor κB (NFκB) signalling activity in a human osteosarcoma cell line (Saos2) results in malignant reversion and the induction of the osteoblast differentiating transcription factor, Runx2/Cbfa1. This observation suggests that there is an inverse relation between a transcription factor associated with malignant progression and chemoresistance (NFκB) and an osteoblast differentiating transcription factor (Runx2/Cbfa1).

Aims:To assess and correlate Runx2/Cbfa1 and NFκB (p65) immunoreactivity in human osteosarcoma.

Methods:Runx2/Cbfa1 and NFκB (p65) immunoreactivity was assessed on 11 paraffin wax embedded archival specimens of human primary osteosarcoma by standard immunohistochemical methods and scored on a scale of 0–3. A Pearson correlation analysis between Runx2/Cbfa1 and NFκB (p65) scores was established.

Results:Runx2/Cbfa1 was expressed constitutively in all pathology specimens of human osteosarcoma. Of note, a chondroblastic osteosarcoma showed the highest Runx2/Cbfa1 immunoreactivity. A Pearson correlation did not support an inverse correlation between Runx2/Cbfa1 and NFκB (p65) scores (r =  0.57) in human osteosarcoma.

Conclusion:Runx2/Cbfa1 immunoreactivity does not inversely correlate with NFκB immunoreactivity, and thus cannot serve as an indirect measure of NFκB activity or an independent predictive or prognostic indicator.
The role of CA125 in clinical practice
Authors: Moss E L , Hollingworth J , Reynolds T M
Published: February 2005

Background:CA125 is a high molecular weight glycoprotein, which is expressed by a large proportion of epithelial ovarian cancers. The sensitivity and specificity of CA125 are poor and there are no guidelines produced by the Royal College of Pathologists or the Association of Clinical Biochemists to aid clinicians and laboratories in its most appropriate use.

Aim:To identify the patient population having a CA125 measurement and to determine its contribution to individual patient management.

Methods:A retrospective case note audit looking at patients who had a CA125 measurement performed between April 2000 and April 2002.

Results:The study comprised 799 patients; 751 (94%) were female and 48 (6%) male; 221 (29%) females and 22 (46%) males had an abnormal result. CA125 was mainly used to investigate a wide range of signs and symptoms, and few tests were for follow up or screening of ovarian cancer. In female patients having a CA125 for suspicion of malignancy/ovarian cancer, only 39 (20%) of the abnormal results were caused by ovarian cancer. False positive results were largely caused by another malignancy (48 cases; 26%), benign ovarian disease (26 cases; 14%), and benign gynaecological conditions, particularly leiomyomas (18 cases; 9%). The specificity of CA125 for ovarian cancer increased with concentrations >1000 kU/litre.

Conclusions:These results confirm the high false positive rate and poor sensitivity and specificity associated with CA125. The substantial inappropriate usage of CA125 has led to results that are useless to the clinician, have cost implications, and add to patient anxiety and clinical uncertainty.
Ultrarapid Ki-67 immunostaining in frozen section interpretation of gliomas
Authors: Haapasalo J , Mennander A , Helen P , Haapasalo H , Isola J
Published: February 2005

Background:Astrocytic tumours, the most common gliomas, are often classified intraoperatively using standard morphological staining. The final diagnosis and grading of gliomas on paraffin wax sections is often assisted by Ki-67 immunohistochemistry, but standard immunostaining protocols take too long to be used intraoperatively.

Aims:To investigate a new rapid Ki-67 immunohistochemical test for its use in an intraoperative setting.

Methods:The new Ki-67 immunostaining (Ultrarapid-Ki67®) method on frozen sections can be carried out in 10 minutes. Thirty four pilocytic and diffuse astrocytomas were immunostained by rapid Ki-67 and results were compared with corresponding MIB-1 staining, histological grading, and prognosis.

Results:The staining protocol was practical to perform and the results were morphologically and quantitatively indistinguishable from those after immunostaining with MIB-1, an antibody recognising Ki-67 in paraffin wax embedded tissue. A comparison of Ultrarapid-Ki67 and MIB-1 immunostaining of paraffin wax sections showed almost identical quantitative correlation in astrocytic gliomas (r = 0.916; p<0.001). The Ultrarapid-Ki67 indices (percentage of positive cells) of low grade (I/II) astrocytomas ranged from 0% to 6.1%, whereas those of representative high grade (III/IV) tumours were significantly higher (range, 5.6–45%; p<0.001). The best prognostic cutoff point for Ultrarapid-Ki67 was 7.5%, which divided diffuse grade II–IV astrocytomas into significantly differing subsets (p = 0.0008).

Conclusion:Ultrarapid-Ki67 immunostaining is a useful adjunct to morphological diagnosis and grading of astrocytic tumours, and as a fast test (∼10 minutes for staining plus three to four minutes for scoring), it could be used in routine intraoperative diagnosis of gliomas and other neoplastic diseases.
Myelodysplastic syndrome with erythroid hypoplasia
Authors: Goyal R , Varma N , Marwaha R K
Published: February 2005

The incidence of myelodysplastic syndrome (MDS) with erythroid hypoplasia/aplasia is probably underestimated because in most patients it is mistaken for acquired pure red blood cell aplasia. This report describes three children who fulfilled the criteria for MDS with erythroid hypoplasia/aplasia. All these patients had transfusion dependent anaemia, reticulocytopenia, erythroid hypoplasia/aplasia, severe dysgranulopoiesis, and dysmegakaryopoiesis.
The use of digital imaging, video conferencing, and telepathology in histopathology: a national survey
Authors: Dennis T , Start R D , Cross S S
Published: February 2005

Aims:To undertake a large scale survey of histopathologists in the UK to determine the current infrastructure, training, and attitudes to digital pathology.

Methods:A postal questionnaire was sent to 500 consultant histopathologists randomly selected from the membership of the Royal College of Pathologists in the UK.

Results:There was a response rate of 47%. Sixty four per cent of respondents had a digital camera mounted on their microscope, but only 12% had any sort of telepathology equipment. Thirty per cent used digital images in electronic presentations at meetings at least once a year and only 24% had ever used telepathology in a diagnostic situation. Fifty nine per cent had received no training in digital imaging. Fifty eight per cent felt that the medicolegal implications of duty of care were a barrier to its use. A large proportion of pathologists (69%) were interested in using video conferencing for remote attendance at multidisciplinary team meetings.

Conclusions:There is a reasonable level of equipment and communications infrastructure among histopathologists in the UK but a very low level of training. There is resistance to the use of telepathology in the diagnostic context but enthusiasm for the use of video conferencing in multidisciplinary team meetings.
CagA in Barrett’s oesophagus in Colombia, a country with a high prevalence of gastric cancer
Authors: Kudo M , Gutierrez O , El-Zimaity H M T , Cardona H , Nurgalieva Z Z , Wu J , Graham D Y
Published: February 2005

Background:In the USA, atrophic gastritis and gastric cancer are rare, whereas gastro-oesophageal reflux disease (GERD) is common. Infection withHelicobacter pylori, especially a CagA positive strain, is unusual in patients with GERD/Barrett’s oesophagus in the USA.

Aim:To examine the relation between Barrett’s oesophagus and CagA positiveH pyloriin Colombia, a country with a high prevalence of CagA positiveH pyloriassociated atrophic gastritis and gastric cancer.

Methods:Helicobacter pyloriand CagA status was determined among Colombian patients with long segment Barrett’s oesophagus and a control group with simpleH pylorigastritis.Helicobacter pyloristatus was determined using a triple stain and CagA status was determined by immunohistochemistry using a specific rabbit anti-CagA serum.

Results:Gastric and oesophageal mucosal biopsies were obtained from 51 patients—39 men (mean age, 57.8 years; SD, 13.1) and 12 women (mean age, 51.8 years; SD, 14.4)—with documented long segment Barrett’s oesophagus. The results were compared with 24 Colombian patients withH pylorigastritis without oesophageal disease. Thirty two patients with Barrett’s oesophagus had activeH pyloriinfection. CagA status was evaluated in a subset of 23H pyloriinfected patients with Barrett’s oesophagus, and was positive in eight of these patients compared with 19 of 24 controls (p  =  0.01).

Conclusions:Although most Colombian patients with Barrett’s oesophagus hadH pyloriinfection, CagA positive infections were unusual. These data illustrate how consistent corpus inflammation reduces acid secretion, which prevents Barrett’s oesophagus among those with abnormal gastro-oesophageal reflux barriers.
Clostridium bacteraemia characterised by 16S ribosomal RNA gene sequencing
Authors: Woo P C Y , Lau S K P , Chan K-m , Fung A M Y , Tang B S F , Yuen K-y
Published: February 2005

Background:Owing to problems in accurate species identification of the diverse genus clostridium, the epidemiology and pathogenicity of many species are not fully understood. Moreover, previous studies on clostridium bacteraemia have been limited and relied only on phenotypic species identification.

Aims:To characterise the epidemiology, disease spectrum, and outcome of clostridium bacteraemia using 16S ribosomal RNA (rRNA) gene sequencing.

Method:During a four year period (1998–2001), all cases of clostridium bacteraemia were prospectively studied and all “non-perfringens” clostridium isolates identified to the species level by 16S rRNA gene sequencing.

Results:Fifty one blood culture isolates were identified asClostridium perfringensand 17 belonged to 11 other clostridium species. The first case ofC disporicuminfection and two cases of clostridium bacteraemia in children with intussusception were also described. Of the 68 clostridium isolates from 68 different patients, 38 were associated with clinically relevant bacteraemia. The gastrointestinal and hepatobiliary tracts were common sites of both underlying disease and portal of entry in these patients.Clostridium perfringensaccounted for 79% of all clinically relevant bacteraemia, with the remainder caused by a diversity of species. The attributable mortality rate of clinically relevant clostridium bacteraemia was 29%. Younger age and underlying gastrointestinal/hepatobiliary tract disease were associated with mortality (p < 0.05).

Conclusions:Patients with clinically relevant clostridium bacteraemia should be investigated for the presence of underlying disease processes in the gastrointestinal or hepatobiliary tracts. 16S rRNA gene analysis will continue to be useful in further understanding the pathogenicity of various clostridium species.
History of the endangered thread-leaved sundew (Drosera filiformis) in southern Nova Scotia
Authors: Landry Mark , Cwynar Les C
Published: February 2005

We used the techniques of plant macrofossil analysis and radiocarbon dating to determine the minimum residence time of the endangered thread-leaved sundew (Drosera filiformis Raf.) in three bogs of southern Nova Scotia. The minimum residence times are 4240 cal. year BP for Swain's Road Bog, 2050 cal. year BP for Villagedale Bog, and very recent (modern radiocarbon age) for Port La Tour Bog, indicating that the species has likely been in the region for the past 4240 years. Analysis of nearby Old School Road Bog, which lacks D. filiformis today, failed to find any evidence that it formerly occurred there, suggesting that it may not have been more widespread in the past than it is today.Key words: Drosera filiformis, thread-leaved sundew, plant macrofossil analysis, radiocarbon dating, bogs, minimum residence time.
The biomass and nutrient levels of Calamagrostis canadensis and Carex stricta under different hydrologic and fungicide regimes
Authors: Wetzel Paul R , van der Valk Arnold G
Published: February 2005

We examined whether fungicide and the subsequent reduction of soilborne pathogenic fungi would differentially enhance the productivity and foliar nutrient content of two coexisting species, Calamagrostis canadensis (Michx.) Beauv. and Carex stricta Lam. This was tested under hydrologic regimes that simulated those in prairie wetlands and included a 32-d cycle (flooded 16 d, dry 16 d), 6-d cycle (flooded 3 d, dry 3 d), flooded, well-watered, and dry hydroperiods. Calamagrostis canadensis biomass increased 26%45% in the wet hydroperiods (6-d cycle, well watered, and flooded) when fungicide was applied but remained fairly constant over all hydroperiods in nonfungicide treatments. Calamagrostis canadensis grown in the wet hydroperiods without fungicide produced the same biomass and growth rates as plants treated with fungicide in the dry hydrologic regime, suggesting that pathogenic fungi in wet hydrologic regimes have the same effect as major environmental stresses such as drought. In contrast, the biomass and growth rate of Carex stricta generally did not vary significantly with fungicide treatment. The only exception was in the rapidly alternating hydroperiod (6-d cycle), where Carex stricta treated with fungicide produced 48% more biomass and grew 46% faster than plants not treated with fungicide. Mean concentrations of foliar phosphorus generally were not significantly different between the fungicide and nonfungicide treatments for either plant species, while foliar nitrogen concentrations were higher in both species when treated with fungicide in the 32-d cycle, dry, and well-watered hydroperiods. The effect of fungicide on the biomass and foliar nutrients of these two co-occurring plant species depended on the species and the hydrologic regime, and our results suggest that seasonal and interannual changes in hydrologic regimes may confer a temporary advantage to one species or the other that, over the long term, allow them to coexist.Key words: benomyl fungicide, foliar nitrogen, foliar phosphorus, hydroperiod, marsh reed grass, wetland.
Establishment of a plastochron index for growth assessment of Phalaenopsis
Authors: Jin Jung-Kang , Chen Hui-Ling , Yu Chih-Wen , Lin Chin-Ho
Published: February 2005

A plastochron index was established for four commercial cultivars of Phalaenopsis: Phalaenopsis 'Taisuco Carol' × (Doritaenopsis 'New Cinderella' × P. 'Isaribi') (Taiwan Sugar Corp., code No. S88-41); Phalaenopsis 'Taisuco Swan' × (P. 'Casablanca Dream' × (P. 'Hohoemi' × P. 'Grace Palm')) (code No. S88-89); Doritaenopsis 'I-Hsin Dreamer' × Phalaenopsis 'Taisuco Harmonylip' (code No. S88-104), and Phalaenopsis aphrodite. The plastochron was based on a 20-mm reference leaf length. Semilogarithmical plots of ln-transformed leaf lengths versus time and linear regression analysis were used to evaluate three criteria of the plastochron index. The results showed that leaves 39 of Phalaenopsis aphrodite and leaves 38 of the other cultivars grow exponentially (r2 values between 0.90 and 0.97). Therefore, leaves that fulfilled all three criteria for the plastochron index were leaves 35 of No. S88-41, leaves 34 of No. S88-89, leaves 56 of No. S88-104, and leaves 45 of Phalaenopsis aphrodite. However the plastochron index can not be used for the slow-growing Phalaenopsis, because two successive leaves could not be measured simultaneously during the exponential phase of leaf development. The average relative growth rate of 0.43 mm/week for Phalaenopsis aphrodite was significantly lower than that of the other three cultivars (0.52 mm/week); plastochron duration also showed significant variation among the four cultivars (P value = 0.0269). In addition, the linear relationship (r2 = 0.970.99) of the plastochron index plotted versus time indicates that the intervals between initiation of successive leaves was equal for each of four cultivars. Thus, for these cultivars of Phalaenopsis, leaves that emerge before the reproductive phase can not be fully assessed by the plastochron index.Key words: plastochron index, Phalaenopsis.
Fungi associated with roots of cucumber grown in different greenhouse root substrates
Authors: Menzies J G , Ehret D L , Koch C , Hall J W , Seifert K A , Bissett J , Barr D JS
Published: February 2005

Hydroponic soilless culture systems are commonly used in the greenhouse industry to mitigate soilborne root pathogens, but root diseases continue to be a major problem. A thorough knowledge of the root zone ecology of greenhouse crops is needed for the successful biological control of root diseases. The objectives of this study were to characterize the fungi associated with symptomless cucumber roots grown using different greenhouse substrates and to determine the effects of these fungi on plant growth. A total of 1250 fungal isolates were collected from cucumber roots grown in soil, rockwool, sawdust, or nutrient film and identified to genus and species. There was a greater density of fungal colonies on roots grown in soil than on roots grown in other substrates. Penicillium (87.2% of all isolates), Trichoderma (4.6%), and Pythium (3.0%) were the most common genera isolated from the cucumber roots. The two most common species were Penicillium oxalicum Currie & Thom (69.9%) and Penicillium janthinellum Biourge(13.4%). Pythium group F, Pythium group G, Pythium aphanidermatum (Edson) Fitzp., and Pythium irregulare Buisman were also isolated from healthy cucumber roots and all except Pythium group F were pathogenic to germinating cucumber seedlings. Treatment of cucumber seeds with Penicillium spp. resulted in significantly greater shoot length, root length, and seedling fresh weight of the resulting cucumber seedlings than did treatment with Trichoderma spp. One isolate of Penicillium janthinellum and one of Aspergillus sp. significantly improved survival of cucumber seedlings growing in a Pythium aphanidermatum-infested medium.Key words: hydroponics, Penicillium, Trichoderma, Pythium, Cucumis sativus.
CommentRubus alceifolius, une espèce exotique envahissante, pourrait-elle progressivement coloniser la totalité d'une forêt tropicale humide ?
Authors: Baret Stéphane , Bourgeois Thomas Le , Strasberg Dominique
Published: February 2005

Few quantitative studies confirm or refute actual theories on the capacity of exotic species to invade and colonize new environments. To evaluate these theories, we tested some biological traits of an invasive bramble (Rubus alceifolius Poiret), known for the importance of its sexual reproduction on lowlands, at La Réunion (Indian Ocean). We studied R. alceifolius seed distribution in one of the last tropical lowland rainforests of the island. Seed count was greater under R. alceifolius patches (> 10 000 seed/m2) than in understoreys not colonized by the bramble (approximately 3000 seed/m2). In R. alceifolius patches, localized within gaps, our results showed that seed-rain and seed-bank before and after the fruit period decreased significantly from the center to the edge of the gap. This pattern was certainly due to the variation in luminosity, which decreased from the center of the gap to the edge. We conclude that seed dispersal of this species within the forest is mainly via running water. A number of seeds (10%20%) were able to wait for a new opening in which to germinate. A small proportion of these seeds remained viable in the soil for many years. Monospecific R. alceifolius patches can be considered nurseries and are the main source for colonization of new areas within the forest. Our quantitative results confirm that copious sexual reproduction, a large soil seedbank, and a high germination rate are biological traits that greatly contribute to the invasiveness of this plant. They also provide important information for forestry services establishing adapted control plans.Key words: seedbank, dissemination, introduced plant, biological invasion, life history traits, viability.
Temporal synchrony and variation in abundance of Atlantic salmon (Salmo salar) in two subarctic Barents Sea rivers: influence of oceanic conditions
Authors: Niemelä Eero , Erkinaro Jaakko , Dempson J Brian , Julkunen Markku , Zubchenko Alexander , Prusov Sergei , Svenning Martin A , Ingvaldsen Randi , Holm Marianne , Hassinen Esa
Published: February 2005

Long-term variation in Atlantic salmon (Salmo salar) stocks was analyzed in two Barents Sea rivers, the Teno and Näätämöjoki, that represent the northernmost distribution area of the species. In contrast to most of the North Atlantic area, these rivers are among a group of northern salmon rivers that, despite wide annual variation in catches, demonstrate no consistent trend for declining abundance. Variations in abundance were generally synchronous for the total catch and numbers of 1-sea-winter (1SW) and 2SW salmon during period of 19722003. Part of the variation observed in catches could be related to ocean climate conditions as the mean seawater temperature in July during the year of smoltification for the Kola section of the Barents Sea was significantly related to numbers of 1SW, 2SW, and 3SW salmon in the large River Teno. In contrast, NAO (North Atlantic Oscillation) indices were not related to salmon catches. The latest increase (19992001) in salmon catches in these rivers reflects both temporarily improved oceanic conditions and past management measures affecting offshore, coastal, and river fisheries.
Factors affecting marine production of Atlantic salmon (Salmo salar)
Authors: Jonsson Bror , Jonsson Nina
Published: February 2005

This paper reviews recent advances in our understanding of factors influencing the marine production of wild Atlantic salmon (Salmo salar). Population abundance has declined during the last 30 years because of decreased marine growth rate, survival-rate, and production of multi-sea-winter fish. Mortality appears density-independent, indicating that the marine abundance is beneath the carrying capacity for the species. Correlations between the North Atlantic Oscillation winter index for the post-smolt year and production variables indicate that unfavourable climatic conditions are partly responsible for the decline. Low sea temperature may be the ultimate reason for the poor salmon production, whereas predation is one proximate mortality factor, which is probably both size and temperature dependent. Low growth rate during cold years was associated with low sea age at maturity and small salmon, contrary to the common observation that fast growth leads to young age at maturity. It is suggested that low water temperature may stimulate lipid storage relative to protein production and that the energy density needed to attain sexual maturity is lower in small than in large salmon. Future research should focus on the relationships between smolt age and (or) size and adult age and (or) size, and the association among water temperature, growth rate, growth efficiency, and age at sexual maturity.
On the static analysis of constrained structural systems
Authors: Eun Hee-Chang , Lee Eun-Taik , Chung Heon-Soo
Published: February 2005

Complete structures might contain so many degrees of freedom that it would be infeasible to perform a structural analysis. The derivation of the equilibrium equations of an entire structure to utilize kinematical compatibility conditions at the interfaces of the substructures requires complicated intermediate processes or numerical schemes for determining multipliers. This study derives an explicit matrix form of the equilibrium equations of structural systems subjected to constraints like compatibility conditions or linear displacement relations. The equation is obtained by minimizing a quadratic form of the variation in unconstrained and constrained displacements with respect to all constrained displacements that satisfy the constraints. And the physical meaning of the constraint forces required to satisfy the constraints is investigated. The validity of the proposed method is illustrated by several applications.Key words: constraints, compatibility, equilibrium equation, generalized inverse.
Simulation of the supercooling process and frazil evolution in turbulent flows
Authors: Ye Shi Qiang , Doering Jay
Published: February 2005

A model to simulate the supercooling process and frazil ice evolution in a counter-rotating flume is developed based on a series of laboratory experiments. The characteristics of the supercooling process were found to be related to air temperature and flow turbulence. Frazil ice growth was observed to follow a log-normal distribution model. The model avoids the need to simulate seeding, secondary nucleation, flocculation–breakup, and gravitational removal. Only the overall heat balance is considered during the entire process. The simulations show good agreements with experimental time–temperature curves and frazil evolution.Key words: supercooling, frazil ice, size distribution, concentration, turbulence, simulation.
A laboratory study of frazil evolution in a counter-rotating flume
Authors: Ye Shi Qiang , Doering Jay , Shen Hung Tao
Published: February 2005

A series of experiments was carried out using a counter-rotating flume that is housed in a computer-controlled cold room. A digital image process system (DIPS) was used to observe frazil ice processes. In particular, the effects of air temperature and flow velocity on the supercooling and frazil ice processes were examined. The super cooling process was found to be strongly related to air temperature and water depth, but only weakly related to water velocity. The water velocity has a strong influence on frazil evolution, frazil size, and number of the particles, however. The measured frazil size distribution by volume was found to be reasonably well approximated by a log-normal distribution. Frazil growth continues in number and size during supercooling and appears to reach a stable state at the end of the principal period of supercooling. All characteristic parameters of the supercooling processes and frazil size distribution were found to be related to the Reynolds number, an index of the intensity of flow turbulence. This information can be used in the development of models of frazil ice dynamics.Key words: supercooling, frazil ice, distribution, flow velocity, air temperature, turbulence.
Rehabilitation criteria for post-tensioned voided-slab bridges
Authors: Scollard C R , Bartlett F M
Published: February 2005

Current rehabilitation practices for aging, post-tensioned, voided-slab bridges typically reduce the geometric properties of the concrete cross section and so permanently increase post-tensioning stresses, change primary and secondary prestress moments, and create new primary and secondary moments because the original concrete restrains shrinkage of the new concrete. These changes affect the resistance of the rehabilitated bridge at limit states specified for new construction in the Canadian Highway Bridge Design Code (CHBDC) and may cause other limit states not currently identified in the CHBDC to govern. Rehabilitation schemes should be checked for a serviceability limit state of tensile stresses due to permanent service loads that exceed the cracking strength of the original concrete, which is typically not detailed to control crack widths. Ultimate limit states to check are (i) flexural resistance over interior supports, where the total factored demand can be increased markedly by the rehabilitation; and (ii) creep-initiated failure of concrete due to permanent compressive stresses. The application of these procedures is illustrated through example calculations for a typical continuous bridge.Key words: post-tensioned concrete, serviceability, ultimate limit state, restrained shrinkage, secondary prestress moments, critical stress, cracking.
Nonlinear modeling of concentrically loaded reinforced blockwork masonry columns
Authors: Köksal Hasan Orhun , Doran Bilge , Ozsoy Ayse Elif , Alacali Sema Noyan
Published: February 2005

Since only a limited number of experimental and analytical studies have been carried out for the purpose of developing strength design procedures for reinforced blockwork masonry columns, there is a certain need for further studies that reflect material properties and behavior of blockwork masonry more closely. This paper deals with a nonlinear finite element modeling of the concentrically loaded reinforced blockwork masonry columns making use of both elasto-plastic and isotropic damage models. If the damage model is enriched with the introduction of a simple relation for the material damage parameter that accounts for the mesh size effect, three-dimensional finite element analyses of columns for the well-known experimental works in the literature are accomplished. Finally, the predictions from both the numerical analyses and the existing expressions for the ultimate load of the masonry columns are compared with the experimental results.Key words: compressive strength, reinforced blockwork masonry column, finite element method, Drucker-Prager yield criterion, isotropic damage theory.
Strengthening of dapped timber beams using glass fibre reinforced polymer bars
Authors: Amy K , Svecova D
Published: February 2005

An economical rehabilitation scheme to strengthen creosote-treated dapped timber stringers in both flexure and shear is proposed. An experimental program was conducted to test stringers under monotonic load in three-point bending load configuration. Eight control beams with no reinforcement, 12 reinforced for flexure only, and 6 reinforced for flexure and shear were tested. Glass fibre reinforced polymer (GFRP) dowel bars were placed at an angle of 60° from the horizontal to reinforce for shear and to bridge the dapped end. Test results from previous studies by Gentile et al. (C. Gentile, D. Svecova, and S.H. Rizkalla. ASCE Journal of Composites for Construction, 6(1): 11–20, 2002.) and Svecova and Eden (D. Svecova and R.J. Eden. Canadian Journal of Civil Engineering, 31: 45–55, 2004) are combined with the results of this investigation for a total sample size of 54 beams. Large sample sizes are essential to study the performance of timber beams strengthened using GFRP bars in various schemes. An overall increase of 70% in the 10th percentile ultimate strength was obtained for stringers reinforced for both flexure and shear. Ductility was increased with the addition of the GFRP reinforcement, but the modulus of elasticity appeared to be unaffected.Key words: timber, bridge, glass fibre reinforced polymer, rehabilitation, modulus of rupture, analysis.
Comparing back-calculated and laboratory resilient moduli of bituminous paving mixtures
Authors: Shalaby Ahmed , Liske Tara , Kavussi Amir
Published: February 2005

The stiffness of bituminous mixes is an important indicator of mix performance and a required input for mechanistic pavement design. Resilient modulus is one of many stiffness indicators of mixes which can be determined using laboratory testing methods or non-destructive field tests such as falling weight deflectometer (FWD) tests through back calculation. In this paper, two Manitoba mixes known as Bituminous B (Bit B) and Bituminous C (Bit C) are analysed using laboratory testing and FWD back calculation. The experiment involved samples from eight paving sites. Each site included two side-by-side sections having a common Bit B surface course over either a Bit B or a Bit C binder course. Cored samples were tested following the guidelines of the long term pavement performance protocol P07 at 5, 25, and 40 °C. The modulus of each layer was also estimated from FWD deflection measurements. Findings include correlations between the various material and test parameters and a comparison between back calculated and laboratory stiffnesses.Key words: falling weight deflectometer, indirect tensile test, resilient modulus, asphalt concrete.
Optimizing geometric design of single-lane roundabouts: consistency analysis
Authors: Easa Said , Mehmood Atif
Published: February 2005

One of the main objectives to promote traffic safety at roundabouts is design consistency. Design consistency ensures that the speed differences along a vehicle path or between conflicting paths are smaller than a specified criterion. Traditionally, roundabout design involves an iterative process. Initially, the vehicle path radii are determined from drawing each path by freehand on the proposed roundabout geometry, and then the speeds along path elements are calculated. The process is repeated until design consistency is satisfied. This paper presents an optimization model that directly provides the design parameters that maximize design consistency. The radii of different vehicle paths (through, right, and left) are mathematically modeled for given design parameters. The optimum design parameters include vehicle path radii, approach entry widths, inscribed circle diameter, circulating width, and central island diameter. The optimization model is applicable to single-lane roundabouts with four legs intersecting at right angles. The proposed model not only makes the design process more efficient, but also guarantees the optimum design consistency.Key words: geometric design, roundabouts, horizontal curve radius, consistency, safety, optimization.