bluuebunny/crossref_metadata_2025 huggingface dataset:
Spontaneous retroperitoneal and rectus muscle hemorrhage as a potentially lethal complication of cirrhosis
Authors: Di Bisceglie Adrian M. , Richart John M.
Published: November 2006

Abstract: Aims/Background: Cirrhosis may be complicated by bleeding from varices at sites of porto‐systemic anastomosis and may be exacerbated by coagulopathy.

Methods: We describe two cases with decompensated cirrhosis who developed spontaneous retroperitoneal hemorrhage, with rectus sheath hematoma additionally in one case.

Results: The diagnosis was readily made by physical examination as both patients had Grey Turner's sign – ecchymosis of the flank. In addition, non‐contrast computed tomography was very useful in confirming the diagnosis. The hemorrhage in both patients was associated with the coagulopathy typical of liver disease. However, one patient had features of disseminated intravascular coagulation initially while the other developed this complication during the course of the illness. Both patients died despite vigorous efforts to correct the coagulopathy together with surgical exploration in one case and angiography in the other.

Conclusions: We speculate that the hemorrhage may have originated from varices within the retroperitoneum and abdominal wall, as both patients had significant hypertension. This suggests that variceal decompression may be useful in the management of such cases in the future.
Serum levels of cytokeratin‐18 (tissue polypeptide‐specific antigen) in liver diseases
Authors: Gonzalez‐Quintela Arturo , Mallo Nieves , Mella Carmen , Campos Joaquín , Perez Luis‐Fernando , Lopez‐Rodriguez Raimundo , Tome Santiago , Otero Esteban
Published: November 2006

Abstract: Objective: The tissue polypeptide‐specific antigen (TPS, cytokeratin‐18, a normal constituent of the hepatocyte cytoskeleton) is a standard tumour marker. This study aimed to evaluate serum TPS levels in patients with liver disease.

Methods: Serum TPS was measured with a commercial immunoassay in 884 individuals (753 outpatients from a liver disease clinic, 131 patients admitted to the hospital with acute liver disease).

Results: Abnormally high (>80 U/l) TPS levels were found in 57.7% (95% CI 54.0–61.3%) of outpatients with liver disease. Elevated TPS levels were observed for all liver diseases, including fatty liver, alcoholic disease, chronic viral hepatitis, autoimmune hepatitis, cholestasis, transplantation, and hepatocarcinoma. TPS levels correlated with liver markers, particularly serum AST. In addition, TPS levels correlated with Knodell's score in patients with chronic hepatitis. TPS was increased in one‐third of patients with normal liver enzyme values. Serum TPS levels decreased after specific therapy in patients with hepatitis C and autoimmune hepatitis. Abnormally high TPS levels were found in the vast majority of patients admitted to the hospital, with markedly high (>800 U/l) values being observed in 47.5% (95% CI 36.1–55.7%) of patients with alcoholic liver disease and in 80.8% (95% CI 60.0–92.7%) of patients with acute hepatitis.

Conclusions: Serum TPS (cytokeratin‐18) is elevated in patients with non‐malignant liver diseases, particularly in those with prominent cytolysis. Further studies are needed to evaluate the use of TPS as a marker of liver disease.
Using Step Activity Monitoring to Characterize Ambulatory Activity in Community‐Dwelling Older Adults
Authors: Cavanaugh James T. , Coleman Kim L. , Gaines Jean M. , Laing Linda , Morey Miriam C.
Published: November 2006

OBJECTIVES: To explore the potential of using step activity monitoring to detect differences in ambulatory activity associated with advancing age and declining function in community‐dwelling seniors.

DESIGN: Cross‐sectional pilot study.

SETTING: General communities of Seattle, Washington; Catonsville, Maryland; and Durham, North Carolina.

PARTICIPANTS: Thirty healthy younger adults, 28 healthy older adults, and 12 older adults reporting functional limitations.

MEASUREMENTS: Ambulatory activity data were collected over 6 days with the StepWatch 3. Average daily values were calculated for number of steps, number of minutes of activity, number of activity bouts, variability of minute‐to‐minute activity, and randomness of minute‐to‐minute activity fluctuations.

RESULTS: Healthy older adults engaged in fewer bouts of activity (P=.03) and displayed less‐variable activity (P=.02) than younger adults. Older adults reporting functional limitations not only engaged in fewer bouts of activity (P=.009) and less variable activity (P<.001) than younger adults, but also accumulated fewer total steps (P=.003) and minutes of activity (P=.008) and had less‐random minute‐to‐minute activity fluctuations (P=.02).

CONCLUSION: Step activity monitoring data were useful for detecting differences in ambulatory activity according to age and functional limitation. Monitor‐based measures reflecting patterns of ambulatory activity show promise for use in studies of physical functioning.
Two Items of Evidence, No Putative Source: An Inference Problem in Forensic Intelligence
Authors: Taroni Franco , Bozza Silvia , Biedermann Alex
Published: November 2006

ABSTRACT:Intelligence analysts commonly associate cases on the basis of similarities found in compared characteristics of scientific evidence. The present paper studies some of the inferential difficulties associated with such operations. An analysis is proposed that breaks down the reasoning process intoinference to common source, andinference to case linkage. The former requires an approach to the difficulty associated with evaluating the similarities of items of evidence from different cases with no putative source being available. The latter requires consideration to be given to the relevance of evidence. Throughout the paper, probability theory is used to describe the nature of the proposed inferences. Graphical models are also introduced with the aim of providing further insight into the dependence and independence relationships assumed to hold among the various propositions considered. Notions from decision theory are used to discuss ways in which intelligence analysts may assist investigators in deciding whether or not cases should be considered as linked.
Periodontal infection profiles in type 1 diabetes
Authors: Lalla Evanthia , Kaplan Selma , Chang Shu‐mei J. , Roth Georg A. , Celenti Romanita , Hinckley Karen , Greenberg Ellen , Papapanou Panos N.
Published: November 2006

Objectives: We investigated the levels of subgingival plaque bacteria and serum IgG responses in patients with type 1 diabetes and non‐diabetic controls of comparable periodontal status.

Material and Methods: Fifty type 1 diabetes patients (mean duration 20.3 years, range 6–41) were age‐and gender‐matched with 50 non‐diabetic individuals with similar levels of periodontal disease. Full‐mouth clinical periodontal status was recorded, and eight plaque samples/person were collected and analysed by checkerboard hybridization with respect to 12 species. Homologous serum IgG titres were assessed by checkerboard immunoblotting. In a sub‐sample of pairs, serum cytokines and selected markers of cardiovascular risk were assessed using multiplex technology.

Results: Among the investigated species, only levels of Eubacterium nodatum were found to be higher in diabetic patients, while none of the IgG titres differed between the groups, both before and after adjustments for microbial load. Patients with diabetes had significantly higher serum levels of soluble E‐selectin (p=0.04), vascular cell adhesion molecule‐1 (VCAM‐1; p=0.0008), adiponectin (p=0.01) and lower levels of plasminogen activator inhibitor‐1 (PAI‐1; p=0.02).

Conclusions: After controlling for the severity of periodontal disease, patients with type 1 diabetes and non‐diabetic controls showed comparable subgingival infection patterns and serum antibody responses.
Prevalence and risk variables for peri‐implant disease in Brazilian subjects
Authors: Ferreira S. D. , Silva G. L. M , Cortelli J. R. , Costa J. E. , Costa F. O.
Published: November 2006

Objectives: The aim of this study was to verify the prevalence of peri‐implant disease and analyse possible risk variables associated with peri‐implant mucositis and peri‐implantitis. The study group consisted of 212 partially edentulous subjects rehabilitated with osseointegrated implants.

Material and Methods: The implants placed were examined clinically and radiographically to assess the peri‐implant status. The degree of association between peri‐implant disease and various independent variables was investigated using a multinomial regression analysis.

Results: The prevalence of peri‐implant mucositis and peri‐implantitis were 64.6% and 8.9%, respectively. In univariate modelling, healthy peri‐implant subjects presented lower plaque scores, less periodontal bleeding on probing, and less time elapsed since placement of supra‐structures. In multivariate analyses, the risk variables associated with increased odds for having peri‐implant disease included: gender, plaque scores, and periodontal bleeding on probing. Presence of periodontitis and diabetes were statistically associated with increased risk of peri‐implantitis. The only two factors, which did not contribute to the presence of the disease, were the time elapsed since placement of supra‐structures and the frequency of visits for maintenance care.

Conclusion: Our data suggest that subjects with periodontitis, diabetes, and poor oral hygiene were more prone to develop peri‐implantitis.
Bone augmentation in rabbit calvariae: comparative study between Bio‐Oss® and a novel β‐TCP/DCPD granulate
Authors: Tamimi Faleh Mariño , Torres Jesús , Tresguerres Isabel , Clemente Celia , López‐Cabarcos Enrique , Blanco Luis Jerez
Published: November 2006

Aim: In the present in vivo study, we compare the bone regeneration capacity of a novel brushite cement synthesized in our laboratory (DTG) with Bio‐Oss® using rabbits as an animal model.

Methods: The study was performed in a group of 14 adult New Zealand rabbits using the bone conduction model. Two titanium cylinders were fixed into perforated slits made on the parietal cortical bone of each rabbit. One cylinder was left empty (negative control) and the other was filled with either Bio‐Oss® or brushite set‐cement granules (test cylinder). Four weeks after the intervention, the animals were sacrificed and biopsies were taken. The following parameters were analysed: bone tissue augmentation, bone mineral density and biomaterial resorption. The comparison of data between the different groups was performed using the Mann–Whitney test with a significance level of p<0.05.

Results: The mean bone mineral density and augmented mineral tissue inside the test cylinders were similar but higher than those of negative controls. Material resorption and bone tissue augmentation were significantly higher in the defects treated with the brushite‐based set cement (p<0.05).

Conclusions: Brushite cement granules were more resorbable and generated more bone tissue than Bio‐Oss® inside the titanium cylinders placed in the rabbit calvaria.
Primary flap closure combined with Emdogain® alone or Emdogain® and Cerasorb® in the treatment of intra‐bony defects
Authors: Bokan Ivan , Bill Josip S. , Schlagenhauf Ulrich
Published: November 2006

Objectives: To compare clinical outcomes of three different modalities of treatment for deep intra‐bony defects.

Material and methods: Fifty‐six patients were paralleled for clinical parameters and randomly assigned to treatment. They displayed one angular defect each with an intra‐bony component 3 mm, probing pocket depth (PPD) and probing attachment level (PAL) 7 mm, and plaque index (PI) <1. Nineteen defects were treated, respectively, with enamel matrix derivative (EMD)+tricalcium phosphate (TCP) or EMD alone and 18 defects with modified Widman flap (MWF). Primary flap closure was used in all three groups. PI, gingival index, bleeding on probing, PPD, PAL, and recession (REC) were measured before and 12 months after treatment.

Results: Treatment with EMD alone yielded a 3.9±1.3 mm PPD decrease and a 3.7±1.0 mm PAL gain (p<0.001), whereas EMD+β‐TCP produced a 4.1±1.2 mm PPD reduction and a 4.0±1.0 mm PAL gain (p<0.001). These outcome parameters did not differ between the two groups. REC increased by 0.7±1.3 mm. After MWF treatment, attachment gain was 2.1±1.4 mm (p<0.001) and PPD reduction was 3.8±1.8 mm, whereas REC increased by 1.5±0.7 mm (p=0.042 versus EMD).

Conclusion: Both EMD treatments showed similar clinical effects, with significant PAL gain and a significantly lower REC increase in comparison with MWF treatment.
Immediate Loading of Brånemark System Implants®: A Comparison Between TiUniteTM and Turned Implants Placed in the Anterior Mandible
Authors: Fröberg Kjell‐Krister , Lindh Christina , Ericsson Ingvar
Published: November 2006

Purpose:  The aim of the present study was to compare the treatment outcome of TiUniteTM‐ and turned‐surfaced Brånemark System® (Nobel Biocare AB, Göteborg, Sweden) implants when applying immediate loading of cross‐arch designed fixed partial dentures in the anterior mandible.

Materials and Methods:  Fifteen patients with edentulous mandibles participated in the study. In one half of the jaw, between the exit of the nerve‐vessel bundle and the midline, one type of implant was placed and in the remaining half the other type. The implants were loaded the day of surgery via a fixed, temporary supra‐construction. Ten days later, the permanent one was screw retained to the implant pillars.

Results:  The present 18‐month clinical trial failed to demonstrate any differences regarding healing and cumulative success rate of an an‐oxidized implant surface (TiUnite) and a turned (turned) one when implants in the anterior mandible were exposed to functional load within 24 hours after installation.

Conclusion:  A high predictability regarding the treatment outcome for immediately loaded Brånemark implants in the anterior mandible was observed. Furthermore, no difference between the traditional turned and the an‐oxidized implant surface (TiUnite) could be observed. However, it has to be stressed that all implants (irrespective of surface) were placed in the anterior mandible and also that all the patients demonstrated a high level of oral hygiene.
Clinical Experiences with Laser‐Welded Titanium Frameworks Supported by Implants in the Edentulous Mandible: A 10‐Year Follow‐Up Study
Authors: Örtorp Anders , Jemt Torsten
Published: November 2006

Background:  Long‐term follow‐up studies for more than 5 years are not available on laser‐welded titanium frameworks.

Purpose:  To report and compare 10‐year data on implant‐supported prostheses in the edentulous mandible provided with laser‐welded titanium frameworks and conventional gold alloy frameworks.

Materials and Methods:  Altogether, 155 patients were consecutively treated with prostheses at abutment level with two generations of fixed laser‐welded titanium frameworks (test groups). A control group of 53 randomly selected patients with conventional gold alloy castings was used for comparison. Clinical and radiographic 10‐year data were collected for the three groups.

Results:  All patients followed‐up for 10 years (n=112) still had fixed prostheses in the mandible (cumulative success rate CSR] 100%). The overall 10‐year cumulative success rate (CSR) was 92.8 and 100.0% for titanium and gold alloy frameworks, respectively. Ten‐year implant cumulative survival rate (CSR) was 99.4 and 99.6% for the test and control groups, respectively. Average 10‐year bone loss was 0.56 (SD 0.45) mm for the titanium group and 0.77 (SD 0.36) mm for the control group (p < 0.05). The most common complications for titanium frameworks were resin or veneer fractures, soft tissue inflammation, and fractures (12.9%) of the metal frame. Loose and fractured implant screw components were below 3%.

Conclusion:  Excellent overall long‐term results with 100% CSR could be achieved with the present treatment modality. Fractures of the metal frames and remade prostheses were more common for the laser‐welded titanium frameworks, and the first generation of titanium frameworks worked poorly when compared with gold alloy frameworks during 10 years (p < 0.05). However, on average more bone loss was observed for implants supporting gold alloy frameworks during 10 years. The reasons for this difference are not clear.
A longitudinal study of medication exposure and xerostomia among older people
Authors: Murray Thomson W. , Chalmers Jane M. , John Spencer A. , Slade Gary D. , Carter Knute D.
Published: November 2006

Objective:  To describe the incidence of xerostomia among a population of older people over a 6‐year period, with particular attention to medications as risk factors.

Background:  Understanding the natural history of xerostomia requires longitudinal epidemiological research, but only one study has examined changes in xerostomia over time. While medication is a recognised risk factor for dry mouth, the role of particular medication categories continues to be controversial.

Materials and methods:  Older South Australians (aged 60+) underwent an interview and dental examination at baseline, and these assessments were repeated 2, 5 and 11 years afterward. Medication data were collected at baseline, 5 and 11 years. Xerostomia data were collected at 5 and 11 years using the Xerostomia Inventory (XI) and a standard question.

Results:  Of the 1205 dentate participants assessed at baseline, 669 remained after 5 years, and 246 were assessed at 11 years. Medication prevalence increased over the observation period, such that 94.8% of the cohort were taking at least one medication by 11 years. The prevalence of xerostomia increased from 21.4% to 24.8% between 5 and 11 years (p > 0.05), and the mean XI score increased from 20.0 (SD, 6.7) to 21.5 (SD, 7.9; p < 0.001). Some 14.7% of participants were incident cases of xerostomia, while 11.4% were remitted cases; 10.1% were cases at both 5 and 11 years. After controlling for gender and ‘baseline’ xerostomia severity (represented by the XI score at 5 years), participants who commenced taking daily aspirin after 5 years had over four times the odds of becoming incident cases, while those who commenced taking a diuretic after 5 years had nearly six times the odds of doing so.

Conclusions:  While the overall prevalence of xerostomia increased during the observation period, there was considerable instability, with one‐quarter of the cohort changing their status. Medication exposure was strongly associated with the incidence of the condition, with recent exposure to diuretics or daily aspirin strongly predicting it.
Oral hygiene of elderly people in long‐term care institutions – a cross‐sectional study
Authors: De Visschere Luc M. , Grooten Lieve , Theuniers Guy , Vanobbergen Jacques N.
Published: November 2006

Objective:  The aim of this cross‐sectional study was to assess the level of oral hygiene in elderly people living in long‐term care institutions and to investigate the relationship between institutional and individual characteristics, and the observed oral cleanliness.

Materials and methods:  Clinical outcome variables, denture plaque and dental plaque were gathered from 359 older people (14%) living in 19 nursing homes. Additional data were collected by a questionnaire filled out by all health care workers employed in the nursing homes.

Results:  Only 128 (36%) residents had teeth present in one or both dental arches. About half of the residents (47%) wore complete dentures. The mean dental plaque score was 2.17 (maximum possible score = 3) and the mean denture plaque score was 2.13 (maximum possible score = 4). Significantly more plaque was observed on the mucosal surface of the denture with a mean plaque score of 2.33 vs. 1.93 on the buccal surface (p < 0.001). In the multiple analyses only the degree of dependency on an individual level was found to be significantly correlated with the outcome dental plaque (odds ratio: 3.09) and only the management of the institution with denture plaque (odds ratio: 0.43).

Conclusion:  Oral hygiene was poor, both for dentures and remaining teeth in residents in long‐term care institutions and only the degree of dependency of the residents and the management of the institutions was associated with the presence of dental plaque and denture plaque respectively.
HPLC ANALYSIS OF RICE BRAN OIL
Authors: KADAM M. , BHOWMICK D.N.
Published: November 2006

A simple isocratic reversed phase high‐performance liquid chromatographic method was developed to study lipase‐catalyzed esterification of high free fatty acid (FFA) rice bran oil. The method was used to separate and quantify FFAs, monoacylglycerols, diacylglycerols and triacylglycerols of rice bran oil as different lipid classes. Separation was obtained with a C18 column using acetone/acetonitrile/methanol (50:50:10, v/v/v) as the mobile phase at 30C with refractive index detection.
SCREENING OF LIPASES FOR ENZYMATIC CONCENTRATION OF γ‐LINOLENIC ACID (GLA) FROM SEED OILS
Authors: LÓPEZ‐MARTÍNEZ J.C. , CAMPRA‐MADRID P. , RAMÍREZ‐FAJARDO A. , ESTEBAN‐CERDÁN L. , GUIL‐GUERRERO J.L.
Published: November 2006

An enzymatic method that involves seed oil hydrolysis and selective esterification of free fatty acids (FFAs) has been essayed for screening of lipases in order to concentrate γ‐linolenic acid (GLA; 18:3n‐6). This procedure has been essayed by using the seed oil of two plant species, Borago officinalis and Echium fastuosum. No GLA enrichment was observed in the FFA fractions resulting from the enzymatic hydrolysis performed by all essayed lipases. However, starting from the FFA fraction of B. officinalis seed oil, and after esterfication with Candida rugosa lipase, in the fatty acid (FA) unesterified fraction a 91% GLA purity was obtained after two successive esterifications, yielding 59% GLA. GLA from E. fastuosum seed oil was also esterified; GLA was concentrated in the FA unesterified fraction by using Mucor javanicus lipase, obtaining 64% purity and 68% GLA yield.
PREFERENCE MAPPING OF TEXTURE OF DULCE DE LECHE
Authors: ARES GASTÓN , GIMÉNEZ ANA , GÁMBARO ADRIANA
Published: November 2006

The texture of 12 commercial samples of dulce de leche was characterized by means of texture profile analysis. Two sensory manual texture attributes (hardness and ropiness) were evaluated by a panel of 11 trained assessors. A panel of 50 consumers evaluated the texture acceptability of the samples using a 9‐point structured scale. Consumers showed highly significant different degrees of liking for the texture of the evaluated samples of dulce de leche. Clusters identified with Pearson's correlation coefficient showed opposite preference patterns and provided more useful information regarding market segmentation than clusters identified with Euclidean distances. External preference mapping and partial least squares regression showed that hardness was a driver of liking for one segment of consumers, whereas for the other one it was a driver of disliking. When all the consumers were considered, external preference mapping indicated that the ideal texture of dulce de leche would be intermediate, showing the importance of identifying preference patterns and suggesting that data averaging in consumer preferences might affect information recovery, and may lead to wrong conclusions. Different preference mapping techniques were compared; it was found out that when the relationship between acceptability and texture attributes was not linear, external preference mapping showed the best results.
DIFFERENTIATION OF SUPRAHYOID ACTIVITY PATTERNS DURING SWALLOWING OF UMAMI‐TASTING FOODS
Authors: MIYAOKA YOZO , ASHIDA ICHIRO , KAWAKAMI SHIN‐YA , MIYAOKA SATOMI
Published: November 2006

In the preceding study, the present authors differentiated the activity patterns of the suprahyoid (SH) muscles during pharyngeal swallowing of tasty and tasteless foods by using “TP” values that assigned activity of electromyograms (EMG) to a standardized time scale. In the present study, we calculated not only the TP values but also the InP values (by subtracting the preceding TP‐10 values from TP) to analyze activity patterns of the SH EMG during pharyngeal swallowing of foods dissolved in unitary (monosodium glutamate [MSG] and disodium inosine‐5′‐monophosphate [IMP]) and binary (MSG + IMP) “umami‐” tasting solutions of low and high concentration. We found that SH activity patterns differed slightly between low and high concentration of unitary and binary umami‐tasting foods, but that SH activity patterns measured while swallowing umami‐tasting foods did not differ from those measured while swallowing sweet‐ or salty‐tasting foods, or tasteless food.
IMPACT OF FROZEN STORAGE ON FLAVOR OF CAPRINE MILK CHEESES
Authors: PARK Y.W. , GERARD P.D. , DRAKE M.A.
Published: November 2006

The impact of freezing and frozen storage on flavor profiles of soft and semisoft caprine milk cheeses was evaluated. Plain soft pasteurized milk cheeses were purchased from a grade A goat dairy and semisoft cheeses were made from pasteurized caprine milk at a university creamery on three separate occasions. Cheeses were assigned to one of four storage regimes: refrigeration (5C) for 30 days; freezing (−20C) for 24 h followed by thawing and refrigeration for 30 days; and frozen storage (−20C) for 3 or 6 months followed by thawing and refrigerated storage. Cheeses were sampled for sensory analysis initially (time 0 and initially after thawing) and subsequently across refrigerated storage. A descriptive sensory panel received 75 h of training on 13 terms for cheese flavor attributes and basic tastes from a previously adopted sensory lexicon for caprine milk cheeses. Cheeses were evaluated by each panelist in duplicate. Freezing and frozen storage had minimal effects on flavor properties of soft or semisoft cheeses (P > 0.05 for most attributes). Concurrent with previous instrumental studies, frozen storage appears to be a viable option for fresh soft caprine milk cheeses to maintain a year‐round supply.
Towards inclusion: Local government, public space and homelessness in New Zealand
Authors: Laurenson Penelope , Collins Damian
Published: November 2006

Abstract:  This paper considers the political and normative dimensions of local government responses to homelessness in New Zealand. It outlines the context for local government action, the approaches adopted by three case study cities, and arguments for rejecting anti‐homeless regulations in favour of supportive policies conducive to forging inclusive public space. It contributes to debates over homelessness policy by articulating an approach that integrates regulatory, funding and leadership roles. It argues that in addressing antisocial behaviour in public spaces, policy‐makers must eschew approaches which effectively criminalize the sight, and status, of poverty.
‘On the rocks’: New Zealand's coastal bach landscape and the case of Rangitoto Island
Authors: Kearns Robin , Collins Damian
Published: November 2006

Abstract:  A distinctive feature of many of New Zealand's coastal landscapes has been the rudimentarily constructed holiday home known as a ‘bach’. In recent years, however, rapidly escalating beachfront property prices, and the associated development of elite residential landscapes, have threatened the status of the bach. This commentary examines the diminishing number of ‘classic’ kiwi baches, and specifically considers the case of Rangitoto, a volcanic island close to central Auckland. Here, the location of baches on publicly owned land has been controversial and the small number that remains symbolize curiosities from another time and place.
Science Literacy and Backward Priorities
Authors: Hobson Art
Published: November 2006

“The life-enhancing potential of science and technology cannot be realized unless the public in general comes to understand science, mathematics, and technology and to acquire scientific habits of mind; without a scientifically literate population, the outlook for a better world is not promising.” [Italics added.]
Reflection with a Twist: The Helical Mirror
Authors: DeWeerd Alan J. , Hill S. Eric
Published: November 2006

Over the last few years, the helical mirror or “spinner” has become a popular decoration for gardens and elsewhere. Even casual observation reveals intriguing optical properties, so the spinner is a good teaching tool. To facilitate student exploration, we suggest some questions and provide brief explanations.
Using Tide Data in Introductory Classes
Authors: De Jong Marvin L.
Published: November 2006

Ocean tides are not typically high in our consciousness here in Missouri, but in teaching astronomy and physical science the subject always comes up, and teachers of physical science and astronomy are all quite familiar with the textbook explanations. Our goal here is not to explain tides1,2 but to make some suggestions about how, on their own, students can discover relationships between hypotheses and actual evidence.
Noise Reduction by Signal Accumulation
Authors: Kraftmakher Yaakov
Published: November 2006

The aim of this paper is to show how the noise reduction by signal accumulation can be accomplished with a data acquisition system. This topic can be used for student projects. In many cases, the noise reduction is an unavoidable part of experimentation. Several techniques are known for this purpose, and among them the signal accumulation is the simplest one. It is based on exactly knowing the period of a signal to be expected. This is possible when the signal is a response to periodic changes of some external parameters set by the experimenter. For instance, the sample may be subjected to periodic changes of temperature, pressure, irradiation, magnetic or electric field, etc. Therefore, the response of the sample is of exactly the same periodicity as the external influence. A source of this influence provides a signal strictly defining the period of the signal.
Rain-Induced Shadows
Authors: Bartlett Albert A.
Published: November 2006

Several times a week I walk by a metal chair that is fastened to a flat concrete slab at an outdoor bus stop here in Boulder. One day I noticed on the concrete a nice shadow image of the woven metal seat of the chair (Fig. 1). The seat and back of the chair are formed from 3.8-cm wide strips of metal spaced 3.8 cm apart. The seat is about 39 cm above the concrete. Here's how I think this shadow image was produced.
Simple and Cooperatively Built Wave Motion Demonstrator
Authors: Cortel Adolf
Published: November 2006

Some designs of simple wave demonstration devices have been described in this journal and elsewhere.1–5 A new simple model can be built using only dowels, binder clips, and loops of thread. Not only can it be easily assembled, stored, or disassembled, but also all the students in a class can cooperate in its building by connecting successive pieces (units), which make the apparatus as long as desired.
A Simple Photometer to Study Skylight
Authors: McIntosh Gordon
Published: November 2006

A simple photometer constructed from an LED and an op amp can be used to measure light in a number of physical situations. A variety of LEDs exist to investigate different wavelength ranges. Combined with an inexpensive transit, the LED photometer can be used to carry out skylight studies and atmospheric optical depth measurements. The activities described in this paper can help students understand why the sky is blue and introduce students to the basics of radiation scattering and planetary atmospheres.
Nitrogen Availability and TOR Regulate the Snf1 Protein Kinase in
Saccharomyces cerevisiae
Authors: Orlova Marianna , Kanter Ellen , Krakovich David , Kuchin Sergei
Published: November 2006

In the yeast
Saccharomyces cerevisiae
, the Snf1 protein kinase of the Snf1/AMP-activated protein kinase (AMPK) family regulates a wide range of responses to stress caused by glucose deprivation. The stress signal is relayed via upregulation of Snf1, which depends on phosphorylation of its activation loop Thr210 residue by upstream kinases. Although Snf1 is also required for coping with various stresses unrelated to glucose deprivation, some evidence suggests a role for low-level basal activity of unphosphorylated Snf1, rather than a specific signaling function. We previously found that Snf1 is required for diploid pseudohyphal differentiation, a developmental response to nitrogen limitation. Here, we present evidence that Snf1 is directly involved in nitrogen signaling. First, genetic analyses suggest that pseudohyphal differentiation depends on the stimulatory phosphorylation of Snf1 at Thr210. Second, immunochemical data indicate that nitrogen limitation improves Thr210 phosphorylation. Analyses of pseudohyphal differentiation in cells with catalytically inactive and hyperactive Snf1 support the role of Snf1 activity. Finally, we show that Snf1 is negatively regulated by the rapamycin-sensitive TOR kinase which plays essential roles in signaling nitrogen and amino acid availability. This and other evidence implicate Snf1 in the integration of signals regarding nitrogen and carbon stress. TOR and Snf1/AMPK are highly conserved in evolution, and their novel functional interaction in yeast suggests similar mechanisms in other eukaryotes.
Novel Mitogen-Activated Protein Kinase MpkC of
Aspergillus fumigatus
Is Required for Utilization of Polyalcohol Sugars
Authors: Reyes Guadalupe , Romans Angela , Nguyen C. Kim , May Gregory S.
Published: November 2006

The genome of
Aspergillus fumigatus
has four genes that encode mitogen-activated protein kinases (MAPKs),
sakA/hogA
,
mpkA
,
mpkB
, and
mpkC
. The functions of the MpkB and MpkC MAPKs are unknown for
A. fumigatus
and the closely related and genetically amenable species
Aspergillus nidulans. mpkC
deletion mutants of
A. fumigatus
were made and their phenotypes characterized. The
mpkC
deletion mutants were viable and had normal conidial germination and hyphal growth on minimal or complete media. This is in contrast to deletion mutants with deletions in the closely related MAPK gene
sakA/hogA
that we previously reported had a nitrogen source-dependent germination phenotype. Similarly, the growth of the
mpkC
deletion mutants was wild type on high-osmolarity medium. Consistent with these two MAP kinase genes regulating different cellular responses, we determined that the
mpkC
deletion mutants were unable to grow on minimal medium with sorbitol or mannitol as the sole carbon source. This result implicates MpkC signaling in carbon source utilization. Changes in mRNA levels for
sakA
and
mpkC
were measured in response to hypertonic stress, oxidative stress, and a shift from glucose to sorbitol to determine if there was overlap in the SakA and MpkC signaling pathways. These studies demonstrated that SakA- and MpkC-dependent patterns of change in mRNA levels are distinct and have minimal overlap in response to these environmental stresses.
A Transcription Factor Cascade Involving Fep1 and the CCAAT-Binding Factor Php4 Regulates Gene Expression in Response to Iron Deficiency in the Fission Yeast
Schizosaccharomyces pombe
Authors: Mercier Alexandre , Pelletier Benoit , Labbé Simon
Published: November 2006

We have identified genes encoding candidate proteins involved in iron storage (
pcl1

+

), the tricarboxylic acid cycle (
sdh4

+

), and iron-sulfur cluster assembly (
isa1

+

) that are negatively regulated in response to iron deprivation. Promoter deletion and site-directed mutagenesis permitted identification of a new
cis
-regulatory element in the promoter region of the
pcl1

+

gene. This
cis
-acting regulatory sequence containing the pentanucleotide sequence CCAAT is responsible for transcriptional repression of
pcl1

+

under low iron supply conditions. In
Schizosaccharomyces pombe
, the CCAAT-binding factor is a heteromeric DNA-binding complex that contains three subunits, designated Php2, Php3, and Php5. Inactivation of the
php2

+

locus negatively affects the transcriptional competency of
pcl1

+

. A fourth subunit, designated Php4, is not essential for the transcriptional activation of target genes under basal and iron-replete conditions. We demonstrate that, in response to iron-limiting conditions, Php4 is required for down-regulation of
pcl1

+

,
sdh4

+

, and
isa1

+

mRNA levels. In vivo RNase protection studies reveal that the expression of
php4

+

is negatively regulated by iron and that this regulated expression requires a functional
fep1

+

gene. The results of these studies reveal that Fep1 represses
php4

+

expression in response to iron. In contrast, when iron is scarce, Fep1 becomes inactive and
php4

+

is expressed to act as a regulatory subunit of the CCAAT-binding factor that is required to block
pcl1

+

,
sdh4

+

, and
isa1

+

gene transcription.
Glutathione Reductase and a Mitochondrial Thioredoxin Play Overlapping Roles in Maintaining Iron-Sulfur Enzymes in Fission Yeast
Authors: Song Ji-Yoon , Cha Joonseok , Lee Joon , Roe Jung-Hye
Published: November 2006

In the fission yeast
Schizosaccharomyces pombe
, the
pgr1

+

gene encoding glutathione (GSH) reductase (GR) is essentially required for cell survival. Depletion of GR caused proliferation arrest at the G
1
phase of the cell cycle under aerobic conditions. Multicopy suppressors that restore growth were screened, and one effective suppressor was found to be the
trx2

+

gene, encoding a mitochondrial thioredoxin. This suggests that GR is critically required for some mitochondrial function(s). We found that GR resides in both cytosolic and organellar fractions of the cell. Depletion of GR lowered the respiration rate and the activity of oxidation-labile Fe-S enzymes such as mitochondrial aconitase and cytosolic sulfite reductase. Trx2 did not reverse the high ratio of oxidized glutathione to GSH or the low respiration rate observed in GR-depleted cells. However, it brought the activity of oxidation-labile Fe-S enzymes to a normal level, suggesting that the maintenance of Fe-S enzymes is a critical factor in the survival of
S. pombe
. The activity of succinate dehydrogenase, an oxidation-insensitive Fe-S enzyme, however, was not affected by GR depletion, suggesting that GR is not required for the biogenesis of the Fe-S cluster. The total iron content was greatly increased by GR depletion and was brought to a nearly normal level by Trx2. These results indicate that the essentiality of GR in the aerobic growth of
S. pombe
is derived from its role in maintaining oxidation-labile Fe-S enzymes and iron homeostasis.
Expressed in the Yeast
Saccharomyces cerevisiae
, Human ERK5 Is a Client of the Hsp90 Chaperone That Complements Loss of the Slt2p (Mpk1p) Cell Integrity Stress-Activated Protein Kinase
Authors: Truman Andrew W. , Millson Stefan H. , Nuttall James M. , King Victoria , Mollapour Mehdi , Prodromou Chrisostomos , Pearl Laurence H. , Piper Peter W.
Published: November 2006

ERK5 is a mitogen-activated protein (MAP) kinase regulated in human cells by diverse mitogens and stresses but also suspected of mediating the effects of a number of oncogenes. Its expression in the
slt2
Δ
Saccharomyces cerevisiae
mutant rescued several of the phenotypes caused by the lack of Slt2p (Mpk1p) cell integrity MAP kinase. ERK5 is able to provide this cell integrity MAP kinase function in yeast, as it is activated by the cell integrity signaling cascade that normally activates Slt2p and, in its active form, able to stimulate at least one key Slt2p target (Rlm1p, the major transcriptional regulator of cell wall genes). In vitro ERK5 kinase activity was abolished by Hsp90 inhibition. ERK5 activity in vivo was also lost in a strain that expresses a mutant Hsp90 chaperone. Therefore, human ERK5 expressed in yeast is an Hsp90 client, despite the widely held belief that the protein kinases of the MAP kinase class are non-Hsp90-dependent activities. Two-hybrid and protein binding studies revealed that strong association of Hsp90 with ERK5 requires the dual phosphorylation of the TEY motif in the MAP kinase activation loop. These phosphorylations, at positions adjacent to the Hsp90-binding surface recently identified for a number of protein kinases, may cause a localized rearrangement of this MAP kinase region that leads to creation of the Hsp90-binding surface. Complementation of the
slt2
Δ yeast defect by ERK5 expression establishes a new tool with which to screen for novel agonists and antagonists of ERK5 signaling as well as for isolating mutant forms of ERK5.
Separating genetic and environmental influences on temporal spawning distributions of largemouth bass (Micropterus salmoides)
Authors: Rogers Mark W , Allen Micheal S , Porak Wesley F
Published: November 2006

Environmental and genetic factors influence fish spawning periodicity (i.e., the distribution of spawning events during the breeding season), but their relative contributions have rarely been evaluated. We evaluated the relative contribution of genetic and environmental effects on spawning periodicity by rearing Florida largemouth bass (FLMB, Micropterus salmoides floridanus) from Lake Okeechobee and intergrade largemouth bass (ILMB, Micropterus salmoides salmoides × M. s. floridanus) from Lake Seminole in a similar environment. Fish from each genetic source population were translocated to experimental ponds at an intermediate latitude in Gainesville, Florida, in September 2003. We used estimated ages of offspring as an index of spawning events to compare spawning distributions between brood sources in ponds and related those results to spawning distributions at source populations for 2004. FLMB began spawning earlier than ILMB in all ponds, and FLMB had a longer spawning season than ILMB. Similarly, FLMB at Lake Okeechobee began spawning earlier and had a longer spawning season than ILMB at Lake Seminole. Environmental factors (e.g., temperature effects) influenced spawning periodicity for both FLMB and ILMB, but spawning periodicity was also influenced by genetic composition in ponds because translocated fish reflected characteristics of their source populations. Thus, both environmental factors and genetic composition influenced spawning periodicity.
A comparison of species assemblages between drainage systems with and without floodgates: implications for coastal floodplain management
Authors: Kroon Frederieke J , Ansell Dean H
Published: November 2006

Coastal floodplains provide essential nursery habitat for a large number of fish and prawn species, many of which are commercially and recreationally important. Human activities in coastal floodplains, such as those associated with agriculture and (or) development, can have detrimental impacts on this nursery function. We examined the potential role of flood mitigation structures, in particular tidal floodgates, in depleting estuarine and inshore fisheries stocks in eastern Australia. We compared species assemblages (abundance and biomass) in reference and gated drainage systems in the Clarence River floodplain (New South Wales, Australia) over a 1-year period. We subsequently determined which environmental variables were associated with the observed patterns in species assemblages. Our results show that abundance, biomass, and assemblages of juvenile fishes and invertebrates differed significantly and consistently between drainage systems with and without floodgates. The major environmental variables of concern in systems with floodgates were (i) presence of a floodgate, (ii) elevated concentrations of nutrients, and (iii) abundance of aquatic weeds. We discuss our findings in light of potential strategies to improve coastal floodplain management for fisheries production purposes.
Discharge and hydraulic interactions in contrasting channel morphologies and their influence on site utilization by spawning Atlantic salmon (Salmo salar)
Authors: Moir Hamish J , Gibbins Chris N , Soulsby Chris , Webb John H
Published: November 2006

Six study sites were selected to represent the range of channel morphologies, extending from dynamic pool–riffle to transitional step–pool/plane bed reach types, used by spawning Atlantic salmon (Salmo salar) in a small upland Scottish stream. The hydraulic functioning of reaches over the range of discharges used by spawning fish was characterized, and the influence of hydraulic heterogeneity and rates of change in discharge on the frequency of spawning was assessed. Relationships between discharge and depths and velocities differed significantly between sites; thus, hydraulic responses to changes in discharge were different. The range of discharges used for spawning differed between sites, although optimum discharges were similar. Integration of hydraulic information with microhabitat suitability predicted that spawning conditions should occur at discharges higher than those utilized by fish. There was no evidence that hydraulically heterogeneous sites were used more frequently than homogeneous ones. Rather, data suggest that the frequency of utilization of sites was governed principally by the availability of suitable sediment. Flow stability was important for spawning, with periods of rapidly varying discharge avoided. It is suggested that the rate of change in discharge should be considered more explicitly when assessing environmental flow needs.
Tributary streams create spatial discontinuities in habitat, biological productivity, and diversity in mainstem rivers
Authors: Kiffney P M , Greene C M , Hall J E , Davies J R
Published: November 2006

Lotic ecosystems are made up of numerous tributary streams forming a complex branching network. The point where smaller tributaries flow into larger rivers, or tributary junctions, may be sites in the network where spatial discontinuities or “hot spots” are created and maintained, because small streams funnel important materials captured from the surrounding landscape and carry them by gravity downstream. We hypothesized that habitat complexity, environmental productivity, and abundance of primary consumers and predators peak in mainstem rivers at or downstream of tributary junctions. We conducted surveys in three river basins and 13 reaches to examine interdependence between tributary streams and the larger rivers they enter. Wood abundance and volume, variability in median substrate size (i.e., substrate heterogeneity), concentrations of nitrogen and phosphorus in water, algal biomass, and abundance of consumers and predators peaked with a higher frequency at or downstream of tributary junctions. For several variables, the size of the tributary relative to the main stem contributed to the strength of tributary affect. These findings suggest that some tributary streams have fundamental effects on the larger rivers they enter. We argue that maintaining the integrity of connections among and between ecosystems is essential for promoting habitat complexity and community structure within river networks.
Hierarchical approach to the assessment of fishing effects on non-target chondrichthyans: case study of Squalus megalops in southeastern Australia
Authors: Braccini J Matías , Gillanders Bronwyn M , Walker Terence I
Published: November 2006

A three-levelled hierarchical risk assessment approach was trialed using piked spurdog (Squalus megalops) to evaluate the suitability of the approach for chondrichthyan species. At level 1, a qualitative assessment indicated that the only fishing-related activity to have moderate or high impact on S. megalops was "capture fishing" by otter trawl, Danish seine, gillnet, and automatic longline methods. At level 2, a semi-quantitative assessment ranked S. megalops at risk because of its low biological productivity and, possibly, its catch susceptibility from cumulative effects across the separate fishing methods. Finally, at level 3, a quantitative assessment showed that population growth is slow even under the assumption of density-dependent compensation where the fishing mortality rate equals the natural mortality rate. Although published information indicates that relative abundance has been stable in several regions of southern Australia, it is concluded that given its low biological productivity, changed fishing practices leading to increased fishing mortality could quickly put S. megalops at high risk. The hierarchical approach appears particularly useful for assessment of chondrichthyan species in data-limited fisheries. This approach allows for a management response at any level, optimizing research and management efforts by identifying and excluding low-risk species from data intensive assessments.