bluuebunny/crossref_metadata_2025 huggingface dataset:
Dead or Alive? The Federalism Revolution and Its Meaning for Public Administration
Authors: Christensen Robert K. , Wise Charles R.
Published: August 2009

Federalism jurisprudence shapes the powers that public administrators have to achieve policy priorities. Federalism, however, is neither static nor simplistic as a concept, and a proper understanding of the environment in which public administrators work rests on a careful analysis of U.S. Supreme Court decisions. The authors review claims that a 2005 decision, Gonzales v. Raich, terminated a federalism revolution that had been ushered in a decade earlier. Does Raich in fact mark the end of the Supreme Court's federalism doctrine? Analysis of this question clarifies whether the past and current Court has articulated any direction touching on administrators' powers at both the national and state levels. The authors argue that before the federalism revolution is declared dead or alive, public administration can better understand the realities of the Supreme Court's doctrinal boundaries by examining a more detailed analysis of jurisprudence for what is says about the foundations of federalism such as the commerce clause, Fourteenth Amendment, Tenth Amendment, Eleventh Amendment, spending clause, and statutory interpretation issues.
Revising the Leadership Paradigm in Sub‐Saharan Africa: A Study of Community‐Based Leadership
Authors: Haruna Peter Fuseini
Published: August 2009

Much of the discourse on leadership in sub‐Saharan Africa emphasizes leader characteristics, skills, styles, and behaviors, while ignoring the relationships, interactions, practical judgments, and unique contexts that make up leadership in everyday cultural community life. This essay argues that the focus on individual leaders hardly reflects leadership as practice in African communities. An alternative, pragmatic view based on unique historicity and cultural community norms is proposed, one that has a chance of fostering social change and institutional transformation.
Antioxidants and periodontitis in 60–70‐year‐old men
Authors: Linden Gerard J. , McClean Kathy M. , Woodside Jayne V. , Patterson Chris C. , Evans Alun , Young Ian S. , Kee Frank
Published: August 2009

Objective: The aim was to investigate the association between periodontal health and the serum levels of various antioxidants including carotenoids, retinol and vitamin E in a homogenous group of Western European men.

Materials and Methods: A representative sample of 1258 men aged 60–70 years, drawn from the population of Northern Ireland, was examined between 2001 and 2003. Each participant had six or more teeth, completed a questionnaire and underwent a clinical periodontal examination. Serum lipid‐soluble antioxidant levels were measured by high‐performance liquid chromatography with diode array detection. Multivariable analysis was carried out using logistic regression with adjustment for possible confounders. Models were constructed using two measures of periodontal status (low‐ and high‐threshold periodontitis) as dependent variables and the fifths of each antioxidant as a predictor variable.

Results: The levels of α‐ and β‐carotene, β‐cryptoxanthin and zeaxanthin were highly significantly lower in the men with low‐threshold periodontitis (p<0.001). These carotenoids were also significantly lower in high‐threshold periodontitis. There were no significant differences in the levels of lutein, lycopene, α‐ and γ‐tocopherol or retinol in relation to periodontitis. In fully adjusted models, there was an inverse relationship between a number of carotenoids (α‐ and β‐carotene and β‐cryptoxanthin) and low‐threshold periodontitis. β‐Carotene and β‐cryptoxanthin were the only antioxidants that were associated with an increased risk of high‐threshold severe periodontitis. The adjusted odds ratio for high‐threshold periodontitis in the lowest fifth relative to the highest fifth of β‐cryptoxanthin was 4.02 (p=0.003).

Conclusion: It is concluded that low serum levels of a number of carotenoids, in particular β‐cryptoxanthin and β‐carotene, were associated with an increased prevalence of periodontitis in this homogenous group of 60–70‐year‐old Western European men.
Clinical and microbiological benefits of strict supragingival plaque control as part of the active phase of periodontal therapy
Authors: Feres Magda , Gursky Lauren Christine , Faveri Marcelo , Tsuzuki Claudia Ota , Figueiredo Luciene Cristina
Published: August 2009

Aim: To compare the clinical and microbiological effects of scaling and root planing (SRP) alone or combined with mechanical [professional plaque control (PPC)] or chemical [chlorhexidine rinsing (CHX)] control of supragingival plaque in the treatment of chronic periodontitis.

Material and Methods: Sixty subjects were randomly assigned to receive SRP alone or combined with PPC (twice a week) or with CHX rinsing (twice a day). The adjunctive treatments began with SRP and were continued for 42 days. Clinical and microbiological examinations were performed at baseline, 2 and 6 months post‐therapy. Subgingival plaque samples were analysed for 38 bacterial species by checkerboard DNA–DNA hybridization.

Results: The two test treatments were more effective in improving probing depth and clinical attachment level (CAL) than SRP alone, even in intermediate and deep sites. CAL gain was better maintained in the CHX group. The most beneficial microbiological changes were observed in CHX‐treated subjects, who showed a significant reduction in the proportions of red and orange complexes, as well as an increase in the proportions of the host‐compatible bacterial species.

Conclusion: Strict plaque control performed during and after SRP improves periodontal treatment outcomes. The greatest microbiological and clinical benefits were observed with the use of CHX rinsing.
Photocarcinogenesis and toxicity of benzoyl peroxide in hairless mice after simulated solar radiation
Authors: Lerche Catharina M. , Philipsen Peter A. , Poulsen Thomas , Wulf Hans Christian
Published: August 2009

Please cite this paper as: Photocarcinogenesis and toxicity of benzoyl peroxide in hairless mice after simulated solar radiation. Experimental Dermatology 2009;

Abstract:  Topical benzoyl peroxide (BPO) gel has long been used to treat acne vulgaris and has recently been combined with clindamycin (BPO‐clin). No skin malignancies have been reported after clinical use of BPO, but there has been concern about the possible carcinogenicity of BPO alone and in combination with UV radiation. BPO can promote skin tumorigenesis in a mouse skin chemical carcinogenesis model. As acne vulgaris is frequently localized on sun‐exposed areas, we investigated whether BPO or BPO‐clin accelerates photocarcinogenesis in combination with simulated solar radiation (SSR) in 12 groups of 25 hairless female C3.Cg/TifBomTac‐immunocompetent mice. BPO or BPO‐clin was applied topically to the back five times each week, followed by SSR three times each week (2, 3, or 4 standard erythema doses) 3–4 h later, for 365 days or until death. Generally BPO and BPO‐clin did not accelerate the time to first, second or third tumor. Therefore, there is no evidence suggesting that BPO or BPO‐clin is photocarcinogenic. However, we found significantly higher mortality in the SSR exposed groups receiving BPO and BPO‐clin compared with groups receiving only BPO or BPO‐clin. Our results show that BPO and the combination of BPO and clindamycin do not accelerate photocarcinogenesis, but are toxic in hairless mice. Based on the current data, the cancer risk associated with the use of BPO and BPO‐clin in sun‐exposed areas is minimal. Thus, while the carcinogenic potential of BPO is not fully understood, at the present time, evidence suggests that this compound is safe to use.
Metabolic responses to submaximal treadmill walking and cycle ergometer pedalling in obese adolescents
Authors: Lafortuna C. L. , Lazzer S. , Agosti F. , Busti C. , Galli R. , Mazzilli G. , Sartorio A.
Published: August 2009

Physical activity is essential in obesity management because of the impact of exercise‐related energy expenditure (EE) and fat oxidation (Fox) rate on a daily balance, but the specific physiological effects of different exercise modalities are scarcely known in obese individuals. The objective of the study was to compare the metabolic responses to treadmill (TM) and cycle ergometer (CE) exercise in obese adolescents. Gas exchange, heart rate (HR), blood lactate (LA) concentration, EE and Fox were determined at different intensity levels (up to about 85% of maximal oxygen uptake) during TM and CE in 14 pubertal (Tanner stage: >3) obese (BMI SDS: 2.15–3.86) male adolescents (age: 13–18 years). At comparable HR, oxygen uptake, EE and Fox were higher, and LA lower, during TM than CE (P<0.05–0.001), suggesting that cycling imposes a metabolic involvement at the level of the single active muscles greater than walking. Therefore, due to different physiological responses to TM and CE, walking was more convenient than cycling in obese adolescents, permitting to attain the same EE at lower HR, with lower blood LA concentration and with greater Fox. These conclusions seem clinically relevant when using exercise as a part of multidisciplinary treatment for juvenile obesity and amelioration of related metabolic disturbances.
A growth curve to model changes in sport participation in adolescent boys
Authors: Maia J. A. R. , Lefevre J. , Claessens A. L. , Thomis M. A. , Peeters M. W. , Beunen G. P.
Published: August 2009

The aims of this study are twofold: (1) to present the latent growth model, its strategy and usefulness in modelling sport participation over a 6‐year period in youngsters (2) and to study the impact of biological maturation in sport participation changes. A standardized sport participation questionnaire using h/week/year as the unit of analysis was applied to 588 Belgium boys 13–18 years of age followed longitudinally for 6 years. Skeletal age was used to estimate biological maturation. Growth curve modelling with robust estimation was used. Sport participation changes showed a curvilinear trend: baseline values (3.18±0.13 h/week/year), a linear trend that indicates the rate of change (0.70±0.11) and a quadratic trend indicating deceleration, i.e. a change in the rate of change (−0.07±0.02) were all statistically significant (P<0.05), as well as inter‐individual differences in these three parameters. Up to 16.8 years, the rate of sports participation increased 0.70 h/week/year and then declined. Biological maturation did not show any association with adolescent changes in sport participation.
Colorimetry provides a rapid objective measurement of de novo hair growth rate in mice
Authors: Tzung Tien‐Yi , Yang Chia‐Yi , Huang Yung‐Chang , Kao Fu‐Jen
Published: August 2009

Background: Depilated mice have been used as a test platform for hair growth‐regulating agents. However, currently available assessment tools for hair growth in mice are less than ideal.

Methods: Tristimulus colorimetry of the fur color of depilated agouti, albino, and black mice with L*, a*, and b* values were performed daily until the full growth of pelage. Using light‐emitting diode (LED) irradiation (650 and 890 nm) with a daily dose of 3.5 J/cm2 as hair growth regulators, the hair growth rates observed by the global assessment were compared with those derived from colorimetry.

Results: In contrast to a* and b* values, L* values changed more drastically over time in the anagen phase regardless of fur color. Unlike the inhibitory effect of 650 nm irradiation, LED of 890 nm promoted de novo hair regrowth in mice. The difference in hair growth rates detected by colorimetry paralleled the observation made by the global assessment.

Conclusion:
The L* value of fur color obtained by tristimulus colorimetry was a sensitive yet quantitative indicator of de novo hair growth, and could be used to project the hair growth rate in mice.
Red Listing: Deciding Which Species are at Risk
Authors: Keith David
Published: August 2009

Darwin explained how species began. Today we may be witnessing the sixth great extinction. Conservationists rely on the so-called “red list” of most-threatened species, but the red list has been criticised as arbitrary, subjective and based on inadequate data. David Keith looks at the science and the statistics of the red list.
Quantifying Biodiversity
Authors: Buckland Steve
Published: August 2009

Darwin's Theory of Evolution explains the astonishing variety of life on earth. But many species are vanishing. We pass resolutions to slow the decline in biodiversity but we cannot tell whether those resolutions are met because we have no effective way of measuring biodiversity. Steve Buckland believes there are solutions.
Cousins: Charles Darwin, Sir Francis Galton and the Birth of Eugenics
Authors: Gillham Nicholas W.
Published: August 2009

Sir Francis Galton, scientist, African Explorer and statistician, was a key figure in statistical history. He was the man who devised the statistical concepts of regression and correlation. He was also Charles Darwin's cousin. And, inspired by his reading of Darwin, he was the founder of eugenics: the “science” of improving the human race through selective breeding. Nicholas Gillham tells of a darker side to statistics and heredity.
Life: What is the Chance that We are Alone?
Authors: Burchell Mark
Published: August 2009

The Earth is full of life. If life evolved here, why not elsewhere? The Universe is a big place and our galaxy has many stars with planets. So are we alone? What is out there? And how do we know?Mark Burchell looks at the probability of life beyond our planet.
Toward a Blue Cultural Studies: The Sea, Maritime Culture, and Early Modern English Literature
Authors: Mentz Steven
Published: August 2009

This article explores the cultural meanings of the maritime world in early modern English literature. Placing English literary culture in the context of the massive ocean‐bound expansion of European culture that began in the 15th century, it suggests that the sea’s ancient meanings shifted in the early modern period as geographic experience and knowledge increased. The article examines some recent developments in maritime studies, sometimes called a ‘new thalassology’ (from the Greek thalassos, the sea); distinguishes these trends from now‐traditional New Historicist and Atlantic studies; and suggests how these methods can contribute to a ‘blue cultural studies’. The new maritime humanities speaks to a series of modern discourses, including globalization, postcolonialism, environmentalism, ecocriticism, and the history of science and technology. The article provides two examples of how these maritime discourses can change our interpretations of early modern English literature, first by examining a canonical poem – Milton’s ‘Lycidas’– and second through reconsidering a historical context, the ‘Bermuda pamphlets’ on which Shakespeare seems to have drawn in The Tempest.
The Saccharomyces cerevisiae vacuolar acid trehalase is targeted at the cell surface for its physiological function
Authors: He Susu , Bystricky Kerstin , Leon Sebastien , François Jean M. , Parrou Jean L.
Published: August 2009

Previous studies in the yeast Saccharomyces cerevisiae have proposed a vacuolar localization for Ath1, which is difficult to reconcile with its ability to hydrolyze exogenous trehalose. We used fluorescent microscopy to show that the red fluorescent protein mCherry fused to the C‐terminus of Ath1, although mostly localized in the vacuole, was also targeted to the cell surface. Also, hybrid Ath1 truncates fused at their C‐terminus with the yeast internal invertase revealed that a 131 amino acid N‐terminal fragment of Ath1was sufficient to target the fusion protein to the cell surface, enabling growth of the suc2Δ mutant on sucrose. The unique transmembrane domain appeared to be indispensable for the production of a functional Ath1, and its removal abrogated invertase secretion and growth on sucrose. Finally, the physiological significance of the cell‐surface localization of Ath1 was established by showing that fusion of the signal peptide of invertase to N‐terminal truncated Ath1 allowed the ath1Δ mutant to grow on trehalose, whereas the signal sequence of the vacuolar‐targeted Pep4 constrained Ath1 in the vacuole and prevented growth of this mutant on trehalose. Use of trafficking mutants that impaired Ath1 delivery to the vacuole abrogated neither its activity nor its growth on exogenous trehalose.
Sediment Hosted Primary Tin Deposit Associated with Biotite Granite and Fault Zone at Gunung Paku, Klian Intan, Upper Perak, Malaysia
Authors: Ariffin Kamar Shah
Published: August 2009

Gunung Paku near Klian Intan, Perak, is a primary tin deposit in Malaysia mined since 200 years ago, contributing 3–5% of tin ore concentrates previously, and recently over 70% of the Malaysian tin. Gunung Paku is located within the western Tin belt of Peninsular Malaysia associated with biotite granite (184–230 Ma) of the Main Range Granitoid which extends up to the southern part of Peninsular and Central Thailand. The primary tin mineralization style at the Gunung Paku is mainly associated with widespread occurrence of sheet‐like quartz veining systems parallel to the strike of the host rocks and confined within a narrow N–S trending fault zone. The mineralization formed within a thick sequence of metasedimentry rock that belongs to the Baling Formation of Palaeozoic age. The host rock of weakly metamorphosed argillite generally experienced strong tropical weathering that resulted in a thick sequence of light grey to light brown oxidized profile. The mineralized veins range from simple quartz‐cassiterite, quartz‐tourmaline‐cassiterite to complex quartz‐cassiterite‐polymetallic sulfide veins. Wall rock alterations at Gunung Paku are mainly characterized by the hypogene type alteration consisting of silicification, tourmalinization, chloritization, sericitization and kaolinization normally adjacent to mineralized quartz veins and brecciated‐fault gouge zones. Pyrite, arsenopyrite, cassiterite, rutile, chalcopyrite, trippkeite (CuAsO4), scorodite, covellite and other secondary iron‐oxyhydroxide are the common metallic minerals that accompanied the tin mineralization. Other minor occurrences include trace amounts of complex lead‐bismuth‐antimony‐molybdenum bearing minerals.
Origin of Bornite Pods in Intrusive Rocks at the Kingking Porphyry Copper‐gold Deposit, Southeastern Mindanao, Philippines
Authors: Imai Akira , Suerte Leilanie Osano , Nishihara Sho
Published: August 2009

At the Kingking porphyry copper‐gold deposit, Compostela Valley, south‐eastern Mindanao, Philippines, bornite pods occur in the brecciated parts in the biotite diorite porphyry, together with the volcanic rock and diorite fragments without associated stockworks of quartz veinlets. These pods are generally elongated in shape and measure several centimeters across their longest axes. They are composed of bornite and chalcopyrite with traces of calaverite. The δ34S of bornite and subordinate chalcopyrite of bornite pods ranging from −2.2‰ to +0.1‰ are similar to the δ34S of sulfides associated with quartz veinlets such as bornite and chalcopyrite ranging from −4.7‰ to ±0.0‰. This suggests that the ultimate source of sulfur is identical for bornite pods and sulfides associated with quartz veinlets. Bornite pods are associated with volcanic rock and dioritic fragments in the brecciated portion of the biotite diorite porphyry. It was observed that some dioritic fragments contain quartz veinlets, which may indicate an earlier episode of mineralization. Fragments of the earlier dioritic intrusive rocks and the volcanic rocks, together with the sulfides were incorporated into the biotite diorite porphyry magma. A molten sulfide is possible for the composition between bornite and intermediate solid solution at ∼800°C. The sulfides from the earlier dioritic intrusive rocks in the molten state were segregated and then eventually coalesce to form the bornite pods in the brecciated section of the biotite diorite porphyry.
Detection of circulating antierythropoietin antibodies in patients with end stage renal disease on regular hemodialysis
Authors: EL‐DIN M. M. , ATTIA F. M. , LABIB S. M. , OMAR W.
Published: August 2009

Recombinant human erythropoietin (rHuEPO) has been successfully and safely used to treat anemia in patients with end stage renal disease (ESRD). The safety profile of rHuEPO had been considered to be excellent with possible exception of hypertension and increased risk of dialysis access thrombosis. Recently, antibody‐mediated pure red cell aplasia associated with administration of rHuEPO has been identified as a cause of major concern; we aimed to detect and evaluate the presence of anti‐EPO antibodies in patients with ESRD on regular dialysis who are using rHuEPO. Serum anti‐EPO antibodies were detected by enzyme‐linked immunosorbant assay technique in a total of 90 patients who are currently on regular hemodialysis and using rHuEPO alpha subcutaneously for more than 6 months. All patients were subjected to full history taking and clinical examination. Complete blood count, reticulocytes count, serum creatinine, blood urea, serum albumin, serum ferritin, and hepatitis markers were performed for all patients. Our results showed that 35 patients (38.9%) had the anti‐EPO antibodies in their blood, while 55 patients (61.1%) did not have the circulating antibodies. The mean hemoglobin (Hb) level was significantly lower in the antibody positive group (8.8 g/dl ± 1.35) than in the antibody negative group (9.42 g/dl ± 1.32) (P = 0.000). The reticulocytes count was also significantly much lower in the patients who had anti‐EPO antibodies with mean of (1.99 ± 1.14) vs. (3.15 ± 0.89) in the antibody negative (P = 0.000). The dose of EPO administrated in both studied groups was insignificantly different. The incidence of anti‐EPO antibodies is high in ESRD patients on maintenance hemodialysis. Its presence is associated with increased incidence of anemia possibly due to immune‐mediated inhibition of erythropoiesis as evidenced by reticulocytopenia.
Manipulation of charged residues within the two‐peptide lantibiotic lacticin 3147
Authors: Deegan Lucy H. , Suda Srinivas , Lawton Elaine M. , Draper Lorraine A. , Hugenholtz Floor , Peschel Andreas , Hill Colin , Cotter Paul D. , Ross R. Paul
Published: August 2009

Lantibiotics are antimicrobial peptides which contain a high percentage of post‐translationally modified residues. While most attention has been paid to the role of these critical structural features, evidence continues to emerge that charged amino acids also play a key role in these peptides. Here 16 ‘charge’ mutants of the two‐peptide lantibiotic lacticin 3147 [composed of Ltnα (2+, 2−) and Ltnβ (2+)] were constructed which, when supplemented with previously generated peptides, results in a total bank of 23 derivatives altered in one or more charged residues. When examined individually, in combination with a wild‐type partner or, in some instances, in combination with one another, these mutants reveal the importance of charge at specific locations within Ltnα and Ltnβ, confirm the critical role of the negatively charged glutamate residue in Ltnα and facilitate an investigation of the contribution of positively charged residues to the cationic Ltnβ. From these investigations it is also apparent that the relative importance of the overall charge of lacticin 3147 varies depending on the target bacteria and is most evident when strains with more negatively charged cell envelopes are targeted. These studies also result in, for the first time, the creation of a derivative of a lacticin 3147 peptide (LtnβR27A) which displays enhanced specific activity.
Microaerobic and anaerobic metabolism of a Methylocystis parvus strain isolated from a denitrifying bioreactor
Authors: Vecherskaya Margarita , Dijkema Cor , Saad Hugo Ramírez , Stams Alfons J. M.
Published: August 2009

An obligate methanotrophic bacterium, strain MTS, was isolated from a methane‐fed microaerobic denitrifying bioreactor. 16S rRNA and DNA–DNA hybridization analysis revealed that this organism was most closely related to Methylocystis parvus, a Type II methanotroph, belonging to the α‐subclass of the Proteobacteria. The metabolism of the bacterium under microaerobic and anaerobic conditions was studied by 13C‐NMR. 13C‐labelled poly‐β‐hydroxybutyrate (PHB) formation occurred in cell suspensions incubated with 13C‐labelled methane at low (5–10%) oxygen concentration. Under these conditions low levels of succinate, acetate and 2,3‐butanediol were formed and excreted into the culture medium. Intracellular PHB degradation was observed in intact cells under anaerobic conditions in the absence of an exogenous carbon source during a long‐term incubation of 90 days. Multiple 13C‐labelled β‐hydroxybutyrate, butyrate, acetate, acetone, isopropanol, 2,3‐butanediol and succinate were identified as products in in vivo13C‐NMR spectra and in the spectra of culture medium during the dynamic PHB degradation. The isolated obligate methanotroph clearly shows a fermentative metabolism of PHB under anaerobic conditions. The excreted products may serve as substrates for denitrifying bacteria.
Models for individual oral health promotion and their effectiveness: a systematic review
Authors: Yevlahova D , Satur J
Published: August 2009

Background:  There is a recognized need to deliver oral health information to people during clinical encounters to enable them to develop personal skills in managing their own oral health. Traditional approaches to individual oral health education have been shown to be largely ineffective and new approaches are required to address personal motivations for preventive behaviour. This systematic review aims to identify and assess the effectiveness of behaviour models as a basis for individual oral health promotion.

Methods:  Electronic databases were searched for articles evaluating the effectiveness of health behaviour models in oral and general health between 2000 and 2007. Eighty‐nine studies were retrieved and data were extracted from the 32 studies that met the inclusion criteria.

Results:  Thirty‐two studies were identified in the fields of clinical prevention and health education, motivational interviewing (MI), counselling, and models based interventions. MI interventions were found to be the most effective method for altering health behaviours in a clinical setting.

Conclusions:  There is a need to develop an effective model for chairside oral health promotion that incorporates this evidence and allows oral health professionals to focus more on the underlying social determinants of oral disease during the clinical encounter. There is potential to further develop the MI approach within the oral health field.
Access to dental care among adults with physical and intellectual disabilities: residence factors
Authors: Pradhan A , Slade GD , Spencer AJ
Published: August 2009

Background:  There is limited information about access and barriers to dental care among adults with disabilities.

Methods:  A mailed questionnaire survey of carers of 18–44‐year‐old South Australians with physical and intellectual disabilities (care recipients; n = 485) in family homes, community housing and institutions. Bivariate associations were tested using chi‐square tests. Odds ratios (ORs) and 95 per cent confidence intervals (CI) were estimated for irregular dental visits (IDV).

Results:  Carers from family homes and community housing were more likely to report problems in obtaining dental care than those at institutions (p < 0.001). Lack of dentists with adequate skills in special needs dentistry (SND) was the most frequently reported problem for carers from family homes and community housing. IDV were less likely (p < 0.01) for care recipients in institutions and community housing than in family homes. After adjusting for care recipients’ age, gender and disability, odds of IDV was lower in community housing (OR = 0.2, 95% CI = 0.1, 0.3) and in institutions (OR = 0.1, 95% CI = 0.04, 0.3) relative to family homes.

Conclusions:  Care recipients in institutions and community housing had better access to dental care than those at family homes. The shortage of dentists in SND and treatment costs needs to be addressed.
The effects of saliva on the erosive potential of three different wines
Authors: Brand HS , Tjoe Fat GM , Veerman ECI
Published: August 2009

Background:  The erosive potential of wine on teeth may be modified by the buffering capacity of saliva. This potential effect was studied for three different wines in vitro and in vivo.

Methods:  The buffering capacity was studied in vitro by stepwise addition of small volumes of a dry white wine, a medium sweet white wine and a red wine to collected stimulated saliva. In vivo, this was studied by six volunteers vigorously rinsing 5 mL of each wine in their mouth for 15 to 45 seconds. Changes in salivary flow rate and pH were measured during a period of 10 minutes after rinsing with 5 mL wine.

Results:  pH values < 5.5 were observed in vitro after addition of 0.2 mL dry white wine and medium sweet wine and after 0.3 mL red wine to 1 mL saliva. During rinsing with all wines, the intra‐oral pH decreased to below 4 within 15 seconds and remained below this value for at least 45 seconds. After expectoration, the salivary pH remained significantly low for two to six minutes, despite a doubling of the flow rate observed during the first two minutes.

Conclusions:  Vigorously rinsing wine induced a decrease in intra‐oral pH of significant degree and duration, which increases the risk of developing dental erosion.
Consumption of milk with added casein phosphopeptide‐amorphous calcium phosphate remineralizes enamel subsurface lesions in situ
Authors: Walker GD , Cai F , Shen P , Bailey DL , Yuan Y , Cochrane NJ , Reynolds C , Reynolds EC
Published: August 2009

Background:  Casein phosphopeptide‐amorphous calcium phosphate (CPP‐ACP) is an anticariogenic agent that is suitable to be added to foods. The aim of this double‐blind, three‐way crossover randomized study was to investigate the capacity of CPP‐ACP, when added to bovine milk, to remineralize enamel subsurface lesions in situ.

Methods:  Ten subjects drank 100 mL of bovine milk containing no added CPP‐ACP (control milk), 0.2% (w/v) CPP‐ACP or 0.3% (w/v) CPP‐ACP, for 30 seconds once daily for 15 days, whilst wearing removable appliances with attached slabs of enamel containing subsurface enamel lesions. After each treatment and a one‐week washout period, subjects crossed over to another treatment and this was repeated until they had consumed each of the three milk products. At the completion of each treatment the enamel slabs were removed and remineralization was determined using microradiography.

Results:  The results demonstrated that all three milk samples remineralized enamel subsurface lesions in situ. However, the two milk samples containing added CPP‐ACP each produced significantly greater remineralization than the control milk.

Conclusions:  The remineralizing effect of CPP‐ACP in milk was dose‐dependent with milk containing 0.2% CPP‐ACP and 0.3% CPP‐ACP producing an increase in mineral content of 81% and 164%, respectively, relative to the control milk.
Severe necrotizing stomatitis and osteomyelitis after chemotherapy for acute leukaemia
Authors: Santos FA , Pochapski MT , Pilatti GL , Kozlowski Jr VA , Goiris FAJ , Groppo FC
Published: August 2009

Background:  Leukaemia is a malignant neoplasm characterized by clonal proliferation of white blood cells within the bone marrow. Despite an increase in the white blood cell count, the leukaemic leukocytes are non‐functional. The oral complications arising in leukaemic patients can be attributed to the direct and indirect effects of immunosuppressive chemotherapy.

Methods:  This case report describes severe maxillary and mandibular necrotizing stomatitis and osteomyelitis in a young female patient after chemotherapy for acute leukaemia. On physical examination, the patient presented malnourished with pale skin, cervical lymphadenitis, frequent fever and generalized pain. The intra‐oral clinical examination found halitosis, multiple ulcers, necrotizing stomatitis and osteomyelitis located in the maxillary and mandibular regions. The necrotizing stomatitis and osteomyelitis were treated locally with atraumatic removal of the necrotized tissues. The patient received a daily preventive protocol consisting of oral hygiene care, including twice daily brushing, and mouthrinses with a solution of chlorhexidine. She was also treated with systemic metronidazole and amoxicillin for 21 days.

Results:  During the course of management the patient's oral condition improved with some re‐epithelialization being noted. However, severe alveolar bone destruction remained evident. Thirty‐two months after presentation of the initial symptoms, the patient died due to complications related to leukaemia recurrence (haemorrhage, sepsis and respiratory distress syndrome).

Conclusions:  Dental monitoring during cancer treatment is imperative in order to emphasize the importance of dental plaque control and the maintenance of a healthy periodontal condition throughout medical treatment.
A measure & conquer approach for the analysis of exact algorithms
Authors: Fomin Fedor V. , Grandoni Fabrizio , Kratsch Dieter
Published: August 2009

For more than 40 years, Branch & Reduce exponential-time backtracking algorithms have been among the most common tools used for finding exact solutions of NP-hard problems. Despite that, the way to analyze such recursive algorithms is still far from producing tight worst-case running time bounds. Motivated by this, we use an approach, that we call “Measure & Conquer”, as an attempt to step beyond such limitations. The approach is based on the careful design of a nonstandard measure of the subproblem size; this measure is then used to lower bound the progress made by the algorithm at each branching step. The idea is that a smarter measure may capture behaviors of the algorithm that a standard measure might not be able to exploit, and hence lead to a significantly better worst-case time analysis.

In order to show the potentialities of Measure & Conquer, we consider two well-studied NP-hard problems: minimum dominating set and maximum independent set. For the first problem, we consider the current best algorithm, and prove (thanks to a better measure) a much tighter running time bound for it. For the second problem, we describe a new, simple algorithm, and show that its running time is competitive with the current best time bounds, achieved with far more complicated algorithms (and standard analysis).

Our examples show that a good choice of the measure, made in the very first stages of exact algorithms design, can have a tremendous impact on the running time bounds achievable.
Local policies for resource usage analysis
Authors: Bartoletti Massimo , Degano Pierpaolo , Ferrari Gian-Luigi , Zunino Roberto
Published: August 2009

An extension of the λ-calculus is proposed, to study resource usage analysis and verification. It features usage policies with a possibly nested, local scope, and dynamic creation of resources. We define a type and effect system that, given a program, extracts a history expression, that is, a sound overapproximation to the set of histories obtainable at runtime. After a suitable transformation, history expressions are model-checked for validity. A program is resource-safe if its history expression is verified valid: If such, no runtime monitor is needed to safely drive its executions.
A study of asynchronous design methodology for robust CMOS-nano hybrid system design
Authors: Chakraborty Rajat Subhra , Bhunia Swarup
Published: August 2009

Among the emerging alternatives to CMOS, molecular electronics based diode-resistor crossbar fabric has generated considerable interest in recent times. Logic circuit design with future nano-scale molecular devices using dense and regular crossbar fabrics is promising in terms of integration density, performance and power dissipation. However, circuit design using molecular switches involve some major challenges: 1) lack of voltage gain of these switches that prevents logic cascading; 2) large output voltage level degradation; 3) vulnerability to parameter variations that affect yield and robustness of operation; and 4) high defect rate. In this article, we analyze some of the above challenges and investigate the effectiveness of asynchronous design methodology in a hybrid system design platform using molecular crossbar and CMOS interfacing elements. We explore different approaches of asynchronous circuit design and compare their suitability in terms of several circuit design parameters. We then develop the methodology and an automated synthesis flow to support two different asynchronous design approaches (
Micropipelines
and
Four phase Dual-rail
) for system designs using nano-crossbar logic stages and CMOS interface data-storage elements. Circuit-level simulation results for several benchmarks show considerable advantage in terms of performance and robustness at moderate area and power overhead compared to two different synchronous implementations.
A hybrid nano-CMOS architecture for defect and fault tolerance
Authors: Simsir Muzaffer O. , Cadambi Srihari , Ivančić Franjo , Roetteler Martin , Jha Niraj K.
Published: August 2009

As the end of the semiconductor roadmap for CMOS approaches, architectures based on nanoscale molecular devices are attracting attention. Among several alternatives, silicon nanowires and carbon nanotubes are the two most promising nanotechnologies according to the ITRS. These technologies may enable scaling deep into the nanometer regime. However, they suffer from very defect-prone manufacturing processes. Although the reconfigurability property of the nanoscale devices can be used to tolerate high defect rates, it may not be possible to locate all defects. With very high device densities, testing each component may not be possible because of time or technology restrictions. This points to a scenario in which even though the devices are tested, the tests are not very comprehensive at locating defects, and hence the shipped chips are still defective. Moreover, the devices in the nanometer range will be susceptible to transient faults which can produce arbitrary soft errors. Despite these drawbacks, it is possible to make nanoscale architectures practical and realistic by introducing defect and fault tolerance. In this article, we propose and evaluate a hybrid nanowire-CMOS architecture that addresses all three problems—namely high defect rates, unlocated defects, and transient faults—at the same time. This goal is achieved by using multiple levels of redundancy and majority voters. A key aspect of the architecture is that it contains a judicious balance of both nanoscale and traditional CMOS components. A companion to the architecture is a compiler with heuristics to quickly determine if logic can be mapped onto partially defective nanoscale elements. The heuristics make it possible to introduce defect-awareness in placement and routing. The architecture and compiler are evaluated by applying the complete design flow to several benchmarks.
VL2
Authors: Greenberg Albert , Hamilton James R. , Jain Navendu , Kandula Srikanth , Kim Changhoon , Lahiri Parantap , Maltz David A. , Patel Parveen , Sengupta Sudipta
Published: August 2009

To be agile and cost effective, data centers should allow dynamic resource allocation across large server pools. In particular, the data center network should enable any server to be assigned to any service. To meet these goals, we present VL2, a practical network architecture that scales to support huge data centers with uniform high capacity between servers, performance isolation between services, and Ethernet layer-2 semantics. VL2 uses (1) flat addressing to allow service instances to be placed anywhere in the network, (2) Valiant Load Balancing to spread traffic uniformly across network paths, and (3) end-system based address resolution to scale to large server pools, without introducing complexity to the network control plane. VL2's design is driven by detailed measurements of traffic and fault data from a large operational cloud service provider. VL2's implementation leverages proven network technologies, already available at low cost in high-speed hardware implementations, to build a scalable and reliable network architecture. As a result, VL2 networks can be deployed today, and we have built a working prototype. We evaluate the merits of the VL2 design using measurement, analysis, and experiments. Our VL2 prototype shuffles 2.7 TB of data among 75 servers in 395 seconds - sustaining a rate that is 94% of the maximum possible.
De-anonymizing the internet using unreliable IDs
Authors: Xie Yinglian , Yu Fang , Abadi Martin
Published: August 2009

Today's Internet is open and anonymous. While it permits free traffic from any host, attackers that generate malicious traffic cannot typically be held accountable. In this paper, we present a system called HostTracker that tracks dynamic bindings between hosts and IP addresses by leveraging application-level data with unreliable IDs. Using a month-long user login trace from a large email provider, we show that HostTracker can attribute most of the activities reliably to the responsible hosts, despite the existence of dynamic IP addresses, proxies, and NATs. With this information, we are able to analyze the host population, to conduct forensic analysis, and also to blacklist malicious hosts dynamically.
In defense of wireless carrier sense
Authors: Brodsky Micah Z. , Morris Robert T.
Published: August 2009

Carrier sense is often used to regulate concurrency in wireless medium access control (MAC) protocols, balancing interference protection and spatial reuse. Carrier sense is known to be imperfect, and many improved techniques have been proposed. Is the search for a replacement justified? This paper presents a theoretical model for average case two-sender carrier sense based on radio propagation theory and Shannon capacity. Analysis using the model shows that carrier sense performance is surprisingly close to optimal for radios with adaptive bitrate. The model suggests that hidden and exposed terminals usually cause modest reductions in throughput rather than dramatic decreases. Finally, it is possible to choose a fixed sense threshold which performs well across a wide range of scenarios, in large part due to the role of the noise floor. Experimental results from an indoor 802.11 testbed support these claims.
Interference alignment and cancellation
Authors: Gollakota Shyamnath , Perli Samuel David , Katabi Dina
Published: August 2009

The throughput of existing MIMO LANs is limited by the number of antennas on the AP. This paper shows how to overcome this limit. It presents interference alignment and cancellation (IAC), a new approach for decoding concurrent sender-receiver pairs in MIMO networks. IAC synthesizes two signal processing techniques, interference alignment and interference cancellation, showing that the combination applies to scenarios where neither interference alignment nor cancellation applies alone. We show analytically that IAC almost doubles the throughput of MIMO LANs. We also implement IAC in GNU-Radio, and experimentally demonstrate that for 2x2 MIMO LANs, IAC increases the average throughput by 1.5x on the downlink and 2x on the uplink.
LIPSIN
Authors: Jokela Petri , Zahemszky András , Esteve Rothenberg Christian , Arianfar Somaya , Nikander Pekka
Published: August 2009

A large fraction of today's Internet applications are internally publish/subscribe in nature; the current architecture makes it cumbersome and inept to support them. In essence, supporting efficient publish/subscribe requires data-oriented naming, efficient multicast, and in-network caching. Deployment of native IP-based multicast has failed, and overlay-based multicast systems are inherently inefficient. We surmise that scalable and efficient publish/subscribe will require substantial architectural changes, such as moving from endpoint-oriented systems to information-centric architectures.

In this paper, we propose a novel multicast forwarding fabric, suitable for large-scale topic-based publish/subscribe. Due to very simple forwarding decisions and small forwarding tables, the fabric may be more energy efficient than the currently used ones. To understand the limitations and potential, we provide efficiency and scalability analysis via simulations and early measurements from our two implementations. We show that the system scales up to metropolitan WAN sizes, and we discuss how to interconnect separate networks.
Towards automated performance diagnosis in a large IPTV network
Authors: Mahimkar Ajay Anil , Ge Zihui , Shaikh Aman , Wang Jia , Yates Jennifer , Zhang Yin , Zhao Qi
Published: August 2009

IPTV is increasingly being deployed and offered as a commercial service to residential broadband customers. Compared with traditional ISP networks, an IPTV distribution network (i) typically adopts a hierarchical instead of mesh-like structure, (ii) imposes more stringent requirements on both reliability and performance, (iii) has different distribution protocols (which make heavy use of IP multicast) and traffic patterns, and (iv) faces more serious scalability challenges in managing millions of network elements. These unique characteristics impose tremendous challenges in the effective management of IPTV network and service.

In this paper, we focus on characterizing and troubleshooting performance issues in one of the largest IPTV networks in North America. We collect a large amount of measurement data from a wide range of sources, including device usage and error logs, user activity logs, video quality alarms, and customer trouble tickets. We develop a novel diagnosis tool called Giza that is specifically tailored to the enormous scale and hierarchical structure of the IPTV network. Giza applies multi-resolution data analysis to quickly detect and localize regions in the IPTV distribution hierarchy that are experiencing serious performance problems. Giza then uses several statistical data mining techniques to troubleshoot the identified problems and diagnose their root causes. Validation against operational experiences demonstrates the effectiveness of Giza in detecting important performance issues and identifying interesting dependencies. The methodology and algorithms in Giza promise to be of great use in IPTV network operations.
Every microsecond counts
Authors: Kompella Ramana Rao , Levchenko Kirill , Snoeren Alex C. , Varghese George
Published: August 2009

Many network applications have stringent end-to-end latency requirements, including VoIP and interactive video conferencing, automated trading, and high-performance computing---where even microsecond variations may be intolerable. The resulting fine-grain measurement demands cannot be met effectively by existing technologies, such as SNMP, NetFlow, or active probing. We propose instrumenting routers with a hash-based primitive that we call a Lossy Difference Aggregator (LDA) to measure latencies down to tens of microseconds and losses as infrequent as one in a million.

Such measurement can be viewed abstractly as what we refer to as a coordinated streaming problem, which is fundamentally harder than standard streaming problems due to the need to coordinate values between nodes. We describe a compact data structure that efficiently computes the average and standard deviation of latency and loss rate in a coordinated streaming environment. Our theoretical results translate to an efficient hardware implementation at 40 Gbps using less than 1% of a typical 65-nm 400-MHz networking ASIC. When compared to Poisson-spaced active probing with similar overheads, our LDA mechanism delivers orders of magnitude smaller relative error; active probing requires 50--60 times as much bandwidth to deliver similar levels of accuracy.