bluuebunny/crossref_metadata_2025 huggingface dataset:
‘Inadequate’ dietary habits and mastication in elderly men
Authors: Liedberg Birgitta , Stoltze Kaj , Norlén Per , Öwall Bengt
Published: February 2007

Objective: The aim of this study was to re‐evaluate data about oral status, mastication and nutrition in elderly men in Malmö, Sweden, recorded in 1985–1987, to assess associations between inadequate dietary habits, oral conditions and masticatory function.

Materials and methods: Four hundred and eighty‐one men, aged 67–68, participated in a comprehensive health examination, including tooth and denture status and masticatory tests. A separate study of dietary habits and nutritional status was made. Ninety‐five men had inadequate dietary habits. The databases of dental/denture status, mastication, nutritional status and social network factors were re‐evaluated for assessment of associations.

Results: No significant differences between those with adequate or inadequate nutrition were found with regard to the number of teeth, occlusal contacts or removable dentures. Also self‐assessed chewing did not show any differences.

Conclusion: Inadequate dietary habits were independent of teeth and denture status. Some correlations to social network conditions could be identified. Overweight, obesity, low physical activity and high alcohol intake were more common among those with inadequate nutritional intake.
Abnormal giant cells in the cerebral lesions of tuberous sclerosis complex
Authors: Mizuguchi Masashi
Published: February 2007

ABSTRACT Tuberous sclerosis complex (TSC) is an autosomal dominant disorder caused by mutations of either of the two tumor suppressor genes,TSC1andTSC2, encoding hamartin and tuberin, respectively. TSC is pathologically characterized by the occurrence of multiple hamartias (focal dysplasias) and hamartomas (benign tumors) in the brain and many other organs. Cortical tubers are hamartias in the cerebral cortex responsible for many neuropsychiatric symptoms of TSC. Unlike TSC‐associated hamartomas, cortical tubers do not result from second somatic mutations of theTSCgene, and the mechanism by which they occur remains obscure. Histologically, the most conspicuous feature of cortical tubers is the presence of abnormal giant cells, which show abnormal size and differentiation. Recent studies on human TSC and its animal models have elucidated the critical roles of hamartin and tuberin regulating the growth and differentiation of neural cells.
Maternal vitamin B12deficiency affects spermatogenesis at the embryonic and immature stages in rats
Authors: Watanabe Toshiaki , Ebara Shuhei , Kimura Sachiko , Maeda Kunihiko , Watanabe Yoshitaka , Watanabe Hiroshi , Kasai Shigenobu , Nakano Yoshihisa
Published: February 2007

ABSTRACT To evaluate the role of cobalamin (Cbl) on spermatogenesis, the effect of dietary vitamin B12deficiency on early spermatogenesis was histologically investigated in male fetuses and newborns in the first filial generation (F1males) of rats. There was no difference in the number of gonocytes and supporting cells of Sertoli in the gonad in male fetuses on day 16 of gestation and in the testes in F1males at 0 days of age between vitamin B12‐deficient (VB12‐D) and vitamin B12‐supplemented (VB12‐S) groups. However, at 21 days of age, a decreased number of spermatogonia and no spermatocytes were observed in the VB12‐D group. Numerous TUNEL positive cells were located among spermatocytes of the spermatogenic epithelium. The ultrastructural features examined using transmission electron microscopy were considered to be indicative of apoptosis. The incidence of seminiferous tubules having apoptotic cells was 51.5% in the VB12‐D group. At 60 days of age, aplasia of the spermatids and spermatozoa was detected in the VB12‐D group. In the connective tissue between the seminiferous tubules, many interstitial Leydig cells and blood vessels were observed in the VB12‐D group, as compared with the VB12‐S group. These changes produced by vitamin B12deficiency can be reversed by providing a VB12‐S diet after weaning at 21 days of age. From these findings, such a vitamin B12deficiency during gestation and lactation could affect the germ cells and especially damage spermatocytes in F1male rats, which indicates that Cbl may be an essential constituent in the meiosis of spermatogenesis.
No teratogenic effect of prenoxdiazine: A population‐based case–control study
Authors: Bártfai Zoltan , Somoskövi Akos , Puhó Erzsébet H. , Czeizel Andrew E.
Published: February 2007

ABSTRACT  The objective of this study was to investigate the human teratogenic potential of oral prenoxdiazine treatment during pregnancy. The analysis of cases with congenital abnormalities and their matched controls without congenital abnormalities was performed in the large population‐based data set of the Hungarian Case–Control Surveillance of Congenital Abnormalities, 1980–1996. Of the 22 843 pregnant women who had offspring with congenital abnormalities, 158 (0.7%) were treated with prenoxdiazine. Of the 38 151 pregnant women who had babies without any defects in the study period (control group), 226 (0.6%) were treated with prenoxdiazine (adjusted prevalence odds ratio, 1.0; 95% confidence interval, 0.8–1.3). The comparison of cases and their matched controls did not show a significantly higher rate of prenoxdiazine treatment during the second and third months of gestation in the total (adjusted prevalence odds ratio, 1.4; 95% confidence interval, 0.9–2.2) or in any group of congenital abnormalities. Treatment with prenoxdiazine during pregnancy did not have any teratogenic risk to the fetus. Thus, prenoxdiazine treatment in pregnant women with an unproductive cough may be beneficial.
Erythropoietin contributes to implantation: Ectopic hemoglobin synthesis in decidual cells of mice
Authors: Yasuda Yoshiko , Sasaki Tohru , Takagawa Masanori , Maeda Mitsuyo , Yasuda Megumi , Atsumi Tadao , Fujita Yoshihiko , Fujita Hiroyoshi
Published: February 2007

ABSTRACT  Erythropoietin, by binding to its receptor, stimulates definitive erythroblasts to accumulate hemoglobin (Hb) by up‐regulating erythroid‐specific genes and causes differentiation of erythroblasts into erythrocytes. In mouse decidua we have found the expression of transcripts for the erythropoietin receptor, the function of which has not yet been elucidated. Erythropoietin signaling was inhibited by the injection of a soluble form of the erythropoietin receptor capable of binding with erythropoietin into the mouse uterine cavity on day 4 of gestation, and pale and defective decidual bodies appeared three days later. These pale decidual bodies contained defective embryos without extension to the ectoplacental region, while normal reddish decidual bodies contained normal developing embryos and expressed embryonic and adult Hb with characteristic location of the respective hemoglobins in which an ɛ‐ or β‐globin signal was confirmed. Furthermore, blocking of erythropoietin signaling destroyed Hb‐containing cells and resulted in apoptosis that caused embryonic death. Thus, erythropoietin‐mediated Hb synthesis is essential for the survival of decidual cells. In addition, although no transcripts for GATA‐1 and erythroid heme enzymes could be detected, genes for β‐globin, as well as non‐specific δ‐aminolevulinate synthase, were expressed and regulated in an erythropoietin‐dependent manner. This is the first evidence that ectopic Hb synthesis exists and that erythropoietin coregulates erythroid (globin) and nonerythroid (δ‐aminolevulinate synthase) genes.
Fronto‐nasal dysplasia and atrio‐ventricular canal in a fetus with trisomy 18 identified by absent nasal bones during first trimester screening scan
Authors: Tonni Gabriele , De Felice Claudio , Asioli Silvia , Ventura Alessandro
Published: February 2007

ABSTRACT  Failed ultrasonographic visualization of nasal bones is associated with an increased risk of fetal malformations. Maternal ethnicity and chromosomal abnormalities influence the incidence and visualization rate of nasal bones. A case of absent nasal bones with fronto‐nasal dysplasia and septated cystic hygroma identified at 13+5 weeks’ gestation in a trisomy 18 fetus is reported. The crown–rump length was 82 mm and the absent nasal bones were associated with micrognathia and a flattened face. The risks for trisomy 21 and 18 were subsequently calculated. The couple refused chorionic villus sampling. At 19 weeks’ gestation a follow‐up scan revealed, apart from the resolution of septated cystic hygroma, hypertelorism, a large interventricular septum defect with an atrio‐ventricular canal and an abnormal A wave Doppler pulsation at the level of the ductus venosus. Bilateral choroid plexus cysts were additional ultrasound findings. At that time, an uneventful cordocentesis was performed showing a 47,XY(+18) karyotype. Termination of pregnancy was achieved and pathologic examination confirmed the ultrasonographically detected fetal malformations. When screening the fetal face for the presence or absence of nasal bones during the first trimester pregnancy scan the following points must be taken into consideration: (i) the ethnicity of the mother; (ii) if the nasal bones are absent, measurement of nuchal translucency and risk calculations for trisomy 21 and trisomy 18 should be performed; (iii) if the calculated risks are high, karyotyping should be recommended; and (iv) determine whether the absent nasal bones are an isolated or an associated finding and, in the latter case, discriminate between minor or major fetal malformations.
Identifying Essential Topics in General and Special Education Introductory Assessment Textbooks
Authors: Campbell Cynthia , Collins Vicki L.
Published: February 2007

We reviewed the five top‐selling introductory assessment textbooks in both general and special education to identify topics contained in textbooks and to determine the extent of agreement among authors regarding the essentialness of topics within and across discipline. Content analysis across the 10 assessment textbooks yielded 73 topics related to 13 categories: Decisions, Law, Technical Adequacy, Plan Assessment, Create Assessment, Score Assessment, Assessment Target, Assessment Type, Assessment Method, Interpret Assessment, Communicate Assessment Results, Assessment Population, and Computer‐Assisted Assessment. Many of the topics identified were consistent with traditional assessment expectations of general and special education environments, while other, arguably important, topics were not identified as essential. The idea of core assessment topics for all teachers is introduced.
Multiple Sources of Evidence: An Analysis of Stakeholders' Perceptions of Various Indicators of Student Learning
Authors: Guskey Thomas R.
Published: February 2007

This study compared different stakeholders' perceived validity of various indicators of student learning used to judge the quality of students' academic performance. Data were gathered from the questionnaire responses of 314 educators in three states that have implemented comprehensive state‐wide assessment programs with high‐stakes consequences both for educators and for students. MANOVA results showed that while educators generally hold similar perceptions, significant differences exist between school administrators and teachers. Administrators perceived the results from nationally normed standardized assessments, state assessments, and district assessments to be more valid indicators of student achievement than did teachers. In contrast, teachers granted more validity to classroom observations and homework completion and quality than did administrators. The implications of these differences for reform initiatives are discussed, particularly with regard to teachers' motivation to improve results.
Quality Control Procedures in the Scoring, Equating, and Reporting of Test Scores
Authors: Allalouf Avi
Published: February 2007

There is significant potential for error in long production processes that consist of sequential stages, each of which is heavily dependent on the previous stage, such as the SER (Scoring, Equating, and Reporting) process. Quality control procedures are required in order to monitor this process and to reduce the number of mistakes to a minimum. In the context of this module, quality control is a formal systematic process designed to ensure that expected quality standards are achieved during scoring, equating, and reporting of test scores. The module divides the SER process into 11 steps. For each step, possible mistakes that might occur are listed, followed by examples and quality control procedures for avoiding, detecting, or dealing with these mistakes. Most of the listed quality control procedures are also relevant for Internet‐delivered and scored testing. Lessons from other industries are also discussed. The motto of this module is: There is a reason for every mistake. If you can identify the mistake, you can identify the reason it happened and prevent it from recurring.
EFFECTS OF EMULSIFIERS ON CRYSTAL BEHAVIOR OF PALM OIL BLENDS ON SLOW CRYSTALLIZATION
Authors: MISKANDAR M.S. , MAN Y.B. CHE , RAHMAN R. ABDUL , AINI I. NOR , YUSOFF M.S.A.
Published: February 2007

The effects of sorbitan tristearate (STS) and soy lecithin on blends of palm oil (PO) and olein by slow crystallization were studied. The blends of PO and olein were melted at 80C for 30 min and slowly cooled at a rate of 0.7C/min for 32 min and at 20 ± 0.1C for 48 min. Nuclear magnetic resonance was used to measure the solid fat content (SFC) development. Crystallization without emulsifier was influenced by trisaturated and disaturated triacylglycerol content of PO manifesting significant (P < 0.05) changes in SFC, crystal dispersion and viscosity, but emulsifiers in the blends disturbed these behaviors. The reaction of lecithin was very selective and was determined that at 0.03%, it generally served as a crystal promoter, while at 0.06–0.09%, it was a crystal inhibitor. Viscosity was closely related to the crystal dispersion in the liquid. The blends had low viscosity with 0.03% lecithin, while blends with high trisaturate content had high viscosity with 0.06% lecithin. STS was generally a crystal inhibitor, although at various levels, it was a crystal promoter for the middle‐range saturates. Slow crystallization process of PO and olein blends with 0.03% lecithin produced homogenous crystals with low SFC and viscosity for fluidized products.
STABILIZATION OF SUNFLOWER OIL WITHMORINGA OLEIFERALEAVES UNDER AMBIENT STORAGE
Authors: ANWAR FAROOQ , SIDDIQ ASMA , IQBAL SHAHID , ASI M. RAFIQUE
Published: February 2007

The effect ofMoringa oleiferaleaves on the stability of sunflower oil (SFO) was investigated. The samples ofM. oleiferaleaves were extracted using 80 and 100% methanol, and 80 and 100% acetone, respectively. Preliminary assessment of antioxidant activity of the extracts was carried out by the estimation of total phenolic contents (TPCs), loss of β‐carotene and percent inhibition of peroxidation in linoleic acid. The TPC of different solvent extracts ofM. oleiferaleaves was 5.32–8.00 g/100 g (dry mass basis). The level of inhibition of peroxidation in the linoleic acid system was 85.00–91.86%. Furthermore, preheated refined, bleached and deodorized (RBD) SFO samples were stabilized with crude extracts at a concentration of 600 ppm and subjected to ambient storage for 2 months. The progression of oxidation was followed by the measurement of peroxide value, conjugated dienes, conjugated trienes, andp‐anisidine values. The overall order of antioxidant efficacy of the extracts ofM. oleiferaleaves, as determined by various antioxidant assays and oxidation parameters, was as follows: 80% methanolic extract,>100% methanolic extract,>80% acetone extract and>100% acetone extract.
THE EFFECT OF D‐ALPHA‐TOCOPHEROL ON THE SOLUBILIZATION OF DIPALMITOYLPHOSPHATIDYLCHOLINE MEMBRANE BY ANIONIC DETERGENT SODIUM DODECYL SULFATE
Authors: DWIECKI KRZYSZTOF , GÓRNAŚ PAWEŁ , JACKOWIAK HANNA , NOGALA‐KAŁUCKA MAŁGORZATA , POLEWSKI KRZYSZTOF
Published: February 2007

The effect of D‐alpha‐tocopherol (alpha‐T) on phospholipid dipalmitoylphosphatidylcholine (DPPC) membrane solubilization in their gel phase by anionic detergent sodium dodecyl sulfate has been studied using fluorescence spectroscopy, turbidometric and optical microscopy methods. The solubilization process of DPPC occurs in the range of seconds, whereas the equilibration of the resulting mixed micelles occurs over a much longer timescale. The turbidity changes reflecting the membrane solubilization depended on the D‐alpha‐T/DPPC ratios and detergent concentration. Increasing alpha‐T concentration embedded into DPPC membrane, up to 10 mol%, decreases the solubility of the membrane by 45%. Endogenous alpha‐T fluorescence indicated that during solubilization, the formation of detergent/alpha‐T/phosphatidylcholine aggregates occurred, which led to the mixed micelle formation. Images of the vesicles obtained by optical micros copy visualized that DPPC membrane solubilization and showed that the presence of alpha‐T in the membrane increases its resistance to detergent solubilization. The observed processes were discussed on the basis of the hydrophobic–hydrophilic balance in the bilayer.
FATTY ACID REGIODISTRIBUTION ANALYSIS OF DIVERGENT ANIMAL TRIACYLGLYCEROL SAMPLES – A POSSIBLE APPROACH FOR SPECIES DIFFERENTIATION
Authors: SZABÓ ANDRÁS , FÉBEL HEDVIG , SUGÁR LÁSZLÓ , ROMVÁRI RÓBERT
Published: February 2007

Possible species specificity was tested in storage lipids of red deer, moose, wild boar, extensively farmed pig, badger, rabbit and goose, by fatty acid positional distribution analysis of triacylglycerols (TAG) and 2‐monoacylglycerols (2MAG). All species were proven to preferentially store monoenoic and n‐6 polyenoic fatty acids in TAGs, and had higher chain length and unsaturation (except pigs) at the sn‐2 position. More symmetric fatty acids were proven to acylate preferentially at the sn‐2 position. In the native TAGs, the high abundance of odd‐chain‐length fatty acids was specific for the ruminants and rabbit. Ruminants had n‐6/n‐3 ratios close to 1, as was the badger, while all other species showed n‐6 dominance. In 2MAGs, pigs had lower unsaturation, in a species‐specific manner. The occurrence frequency of n‐9 acids was lower at the sn‐2 position only in pigs. The determination of the fatty acid positional distribution seems to be powerful in sample differentiation.
ASSOCIATION BETWEEN THE DIETARY LIPID INTAKE AND THE DEVELOPMENT OF ORAL PRECANCEROUS LESIONS IN UNIVERSITY STUDENTS
Authors: ACTIS ADRIANA , PEROVIC NILDA , BIGLIANI VIRGINIA , BERTOLOTTO PATRICIA
Published: February 2007

Although the effects of dietary lipids on cancer have been reported, no references were found with respect to oral precancerous lesions (OPLs). The purpose of this study was to analyze the association between the dietary lipids and the risk of developing OPL in university students. Ninety‐eight out of 658 examined subjects of both sexes, age range 18–45 years old, were distributed in 30 cases and 68 controls. After clinical diagnosis of OPL and selection of controls, a food frequency and non‐nutritional factor‐based questionnaires were applied to both groups. A positive association was observed for a low intake of total saturated fatty acids (FAs) (95% confidence interval [CI] = 1.31–24.40) and of stearic acid 18:0 (95% CI = 1.25–35.11) while an inverse association was found for butyric acid 4:0 (95% CI = 0.03–0.69). An inverse trend was observed for a high intake of saturated lauric acid 12:0 (90% CI = 0.11–0.97) and myristic acid 14:0 (90% CI = 0.07–0.96), total polyunsaturated (90% CI = 0.09–0.94) and polyunsaturated linoleic acid 18:2 (90% CI = 0.08–0.90) and ω‐3 tymnodonic acid 20:5 FAs (90% CI = 0.08–0.91) as well as a positive trend of a low intake of total fat (90% CI = 1.04–9.73) and monounsaturated palmitoleic acid 16:1 FA (90% CI = 1.06–10.52). Although further research is required, dietary lipids appear to be associated with the development of OPL in 18‐ to 45‐year‐old university students.
Strain Accumulation in Polymer Electrolyte Membrane and Membrane Electrode Assembly Materials During a Single Hydration/Dehydration Cycle
Authors: Hector Louis G. , Lai Yeh-Hung , Tong Wei , Lukitsch Michael J.
Published: February 2007

A digital image correlation technique was used to measure drying-induced strains in perfluorosulfonic acid (PFSA) membrane and membrane electrode assembly (MEA) materials which are key components of fuel cells. Circular coupons of each material were constrained in a stainless-steel drum fixture and hydration was achieved by immersing the drum/coupon assembly in 80°C water for 5min. During air drying at 25°C and 50% relative humidity, a series of 1280×960 digital images of each coupon surface was recorded with a digital camera and image acquisition system for drying periods up to 26h. Cumulative correlation of an initial image recorded prior to hot water immersion and the final image at the end of drying produced in-plane strain contour maps. Incremental correlation was employed to track strain evolution at the coupon centers and at peripheral points. During the earliest drying stages, where both materials exhibited viscoelastic behavior, peak radial strains of 9.50% and 2.50% were measured in the PFSA membrane and MEA materials, respectively. At longer drying times, peak radial strains reached constant values of 5.70% and 1.25% in the PFSA membrane and MEA materials, respectively. Strain accumulation in the MEA tends to be less uniform than that in the membrane, and corresponding peak strain values in the MEA tend to be less than those in the membrane independent of drying duration. Reinforcement from the electrode layers lowers strain accumulation in the MEA, but it does not preclude crack nucleation in these layers as drying proceeds.
Novel Nanostructured Media for Gas Storage and Transport: Clathrate Hydrates of Methane and Hydrogen
Authors: Di Profio Pietro , Arca Simone , Germani Raimondo , Savelli Gianfranco
Published: February 2007

In the last years the development of fuel cell (FC) technology has highlighted the correlated problem of storage and transportation of gaseous fuels, particularly hydrogen and methane. In fact, forecasting a large scale application of the FC technology in the near future, the conventional technologies of storage and transportation of gaseous fuels will be inadequate to support an expectedly large request. Therefore, many studies are being devoted to the development of novel efficient technologies for gas storage and transport; one of those is methane and hydrogen storage in solid, water-based clathrate hydrates. Clathrate hydrates (CH) are nonstoichiometric, nanostructured complexes of small “guest” molecules enclosed into water cages, which typically form at relatively low temperature-high pressure. In nature, CH of natural gas represent an unconventional and unexploited energy source and methane hydrate technology is already applied industrially. More recently, striking literature reports showed a rapid approach to the possibility of obtaining hydrogen hydrates at room temperature/mild pressures. Methane hydrate formation has been shown to be heavily promoted by some chemicals, notably amphiphiles. Our research is aimed at understanding the basic phenomena underlying CH formation, with a goal to render hydrate formation conditions milder, and increase the concentration of gas within the CH. In the present paper, we show the results of a preliminary attempt to relate the structural features of several amphiphilic additives to the kinetic and thermodynamic parameters of methane hydrate formation—e.g., induction times, rate of formation, occupancy, etc. According to the present study, it is found that a reduction of induction time does not necessarily correlate to an increase of the formation rate and occupancy, and so on. This may be related to the nature of chemical moieties forming a particular amphiphile (e.g., the hydrophobic tail, head group, counterion, etc.). Moreover, a chemometric approach is presented which is aimed at obtaining information on the choice of coformers for H2 storage in hydrates at mild pressures and temperatures.
Preparation of Highly Stable Ion Exchange Membranes by Radiation-Induced Graft Copolymerization of Styrene and Bis(vinyl phenyl)ethane Into Crosslinked Polytetrafluoroethylene Films
Authors: Yamaki Tetsuya , Tsukada Junichi , Asano Masaharu , Katakai Ryoichi , Yoshida Masaru
Published: February 2007

We prepared novel ion exchange membranes for possible use in polymer electrolyte fuel cells (PEFCs) by the radiation-induced graft copolymerization of styrene and new crosslinker bis(vinyl phenyl)ethane (BVPE) into crosslinked polytetrafluoroethylene (cPTFE) films and subsequent sulfonation and then investigated their water uptake, proton conductivity, and stability in an oxidizing environment. In contrast to the conventional crosslinker, divinylbenzene (DVB), the degree of grafting of styrene∕BVPE increased in spite of high crosslinker concentrations in the reacting solution (up to 70mol%). Quantitative sulfonation of the aromatic rings in the crosslinked graft chains resulted in the preparation of membranes with a high ion exchange capacity that reached 2.9meq∕g. The bulk properties of the membranes were found to exceed those of Nafion membranes except for chemical stability. The emphasis was on the fact that the BVPE-crosslinked membranes exhibited the higher stability in the H2O2 solution at 60°C compared to the noncrosslinked and DVB-crosslinked ones, as well as decreased water uptake and reasonable proton conductivity. These results are rationalized by considering the reactivity between styrene and the crosslinker, which is an important factor determining the distribution of the crosslinks in the graft component. In the case of BVPE, the crosslinks at a high density were homogeneously incorporated even into the interior of the membrane because of its compatibility with styrene while the far too reactive DVB led to a crosslink formation only near the surface. The combination of both the cPTFE main chain and BVPE-based grafts, i.e., a perfect “double” crosslinking structure, is likely to effectively improve the membrane performances for PEFC applications.
Performance of Internal and External Reforming Molten Carbonate Fuel Cell Systems
Authors: Musa A. , Steeman H. J. , De Paepe M.
Published: February 2007

Molten carbonate fuel cells (MCFC) are a promising alternative power source for distributed or residential power plants. Therefore, thermodynamic models are built in an Aspen customer modeler for the externally reformed (ER) MCFC and internally reformed (IR) MCFC. These models are integrated in Aspen Plus™. In this article the performance of internal and external reforming molten carbonate fuel cell systems are investigated. To this end the gas temperature at the anode inlet is varied to be able to exam the effect of operating temperature on the operating conditions for different modes of MCFC systems in a range between 600 and 700°C. It is found that the operating temperature has more effect on the cell voltage of IR-MCFC system compared to ER-MCFC system. Simulations show that the IR-MCFC system is more efficient than the ER-MCFC system. The cycle efficiency is rather independent of the operating temperature for as well ER-MCFC as IR-MCFC systems.
Physicochemical Properties of Alkaline Aqueous Sodium Metaborate Solutions
Authors: Cloutier Caroline R. , Alfantazi Akram , Gyenge Elod
Published: February 2007

Background: The transition to a hydrogen fuel economy is hindered by the lack of a practical storage method and concerns associated with its safe handling. Chemical hydrides have the potential to address these concerns. Sodium borohydride (sodium tetrahydroborate, NaBH4), is the most attractive chemical hydride for H2 generation and storage in automotive fuel cell applications, but recycling from sodium metaborate (NaBO2), is difficult and costly. An electrochemical regeneration process could represent an economically feasible and environmentally friendly solution. Method of Approach: We report a study of the properties of concentrated NaBO2 alkaline aqueous solutions that are necessary to the development of electrochemical recycling methods. The solubility, pH, density, conductivity, and viscosity of aqueous NaBO2 solutions containing varying weight percentages (1, 2, 3, 5, 7.5, and 10wt.%) of alkali hydroxides (NaOH, KOH, and LiOH) were evaluated at 25°C. The precipitates formed in supersaturated solutions were characterized by x-ray diffraction and scanning electron microscopy. Results: All NaBO2 physicochemical properties investigated, except solubility, increased with increased hydroxide ion concentration. The solubility of NaBO2 was enhanced by the addition of KOH to the saturated solution, but decreased when LiOH and NaOH were used. The highest ionic conductivity (198.27S∕m) was obtained from the filtrate of saturated aqueous solutions containing more than 30wt.%NaBO2 and 10wt.% NaOH prior to filtration. At 10wt.% hydroxide, the viscosity of the NaBO2 solution was the highest in the case of LiOH (11.38 cP) and lowest for those containing NaOH (6.37 cP). The precipitate was hydrated, NaBO2 for all hydroxides, but its hydration level was unclear. Conclusions: The use of KOH as the electrolyte was found to be more advantageous for the H2 storage and generation system based on NaBO2 solubility and solution half-life. However, the addition of NaOH led to the highest ionic conductivity, and its use seems more suitable for the electroreduction of NaBO2. Further investigations on the impact of KOH and NaOH on the electroreduction of NaBO2 in aqueous media have the potential to enhance the commercial viability of NaBH4.
The Standing Wave on a String as an Oscillator
Authors: Sobel Michael
Published: February 2007

In the usual treatment of waves in introductory courses, one begins with traveling waves and the frequency/wavelength relationship fλ = v, where v is the wave velocity. One then makes the point about superposition and shows that two waves traveling in opposite directions can add up to a standing wave; Eq. (1) still applies. This approach is problematic in two ways: (1) The motion being described, standing waves, has no apparent “velocity,” and so it seems unnecessarily complex—perhaps unreasonably complex—to construct it out of moving waves; (2) It is not easy to derive the formula for the velocity of waves, especially for an audience without calculus or without multi-variate calculus (the wave equation).
Material and Optical Densities
Authors: Gluck Paul
Published: February 2007

The bending of a laser beam in a medium with a density and refractive index gradient in the same direction has been described previously.1–3 When a transparent container is half filled with a salt or sugar solution and an equal amount of water is floated on top of it, then diffusion will create a concentration gradient from top to bottom. A laser light beam shone from the side of the container will then be bent gradually. Its path is shown in Fig. 1.
Ultrasonic Interferometers Revisited
Authors: Greenslade Thomas B.
Published: February 2007

I have been tinkering with ultrasonic transducers once more. In earlier notes I reported on optics-like experiments performed with ultrasonics,1 described a number of ultrasonic interferometers,2 and showed how ultrasonic transducers can be used for Fourier analysis.3 This time I became interested in trying the technique of using two detectors in acoustic interferometers instead of the usual one.
How Circulation of Water Affects Freezing in Ponds
Authors: Moreau Theresa , Lamontagne Robert , Letzring Daniel
Published: February 2007

One means of preventing the top of a pond from freezing involves running a circulating pump near the bottom to agitate the surface and expose it to air throughout the winter months. This phenomenon is similar to that of the flowing of streams in subzero temperatures and to the running of taps to prevent pipe bursts in winter. All of these cases appear to support the assertion that “flowing water does not freeze,” a myth debunked in the case of shaken water in the December 2004 issue of TPT.1
“Physics with a Smile”—Explaining Phenomena with a Qualitative Problem-Solving Strategy
Authors: Mualem Roni , Eylon Bat-Sheva
Published: February 2007

Various studies indicate that high school physics students and even college students majoring in physics have difficulties in qualitative understanding of basic concepts and principles of physics.1–5 For example, studies carried out with the Force Concept Inventory (FCI)1,6 illustrate that qualitative tasks are not easy to solve even at the college level. Consequently, “conceptual physics” courses have been designed to foster qualitative understanding, and advanced high school physics courses as well as introductory college-level courses strive to develop qualitative understanding. Many physics education researchers emphasize the importance of acquiring some qualitative understanding of basic concepts in physics as early as middle school or in the context of courses that offer “Physics First” in the ninth grade before biology or chemistry.7 This trend is consistent with the call to focus the science curriculum on a small number of basic concepts and ideas, and to instruct students in a more “meaningful way” leading to better understanding. Studies7–10 suggest that familiar everyday contexts (see Fig. 1) are useful in fostering qualitative understanding.
Teaching Physics Using Appropriate Technology Projects
Authors: Pearce Joshua M.
Published: February 2007

Appropriate technologies able to be easily and economically constructed from readily available materials by local craftspeople have a central role in the alleviation of poverty in the developing world. However, research and development of these technologies are generally apportioned relatively modest support by the developed world's institutions, in part because the operation of many of these appropriate technologies is dependent on relatively well-understood science accessible even to introductory college physics students. This paper describes a project-based assignment used to capitalize on this opportunity to motivate students to learn physics by offering them a chance to make concrete contributions to the optimization of appropriate technologies for sustainable development.
Hydraulic Capacitor Analogy
Authors: Baser Mustafa
Published: February 2007

Students have difficulties in physics because of the abstract nature of concepts and principles.1 One of the effective methods for overcoming students' difficulties is the use of analogies to visualize abstract concepts to promote conceptual understanding.2,3 According to Iding,4 analogies are consistent with the tenets of constructivist learning theories, which claim that learners should be actively involved and new concepts should be based on learners' previous experiences. When analogies are used during the teaching-learning process, they may promote students' understanding of abstract science concepts.5 This paper suggests a capacitor analogy that aims to foster students' conceptual understanding of capacitors in a slightly different way than Greenslade's analogy.6
A Measurement of g Listening to Falling Balls
Authors: White J. A. , Medina A. , Román F. L. , Velasco S.
Published: February 2007

A ball placed on the edge of a horizontal table is hit with a pendulum and thrown over the floor. The fall time is measured by recording the sounds produced by the collisions with the pendulum and the floor. If the height of the ball with respect to the floor is known, one can determine the acceleration of gravity.
Snell's Law with Large Blocks
Authors: Lynch John J.
Published: February 2007

The introductory physics lab curriculum usually has one experiment devoted to the study of the refraction of light. The most obvious way to study the refraction of light is to lay a transparent block down on the lab bench and aim a laser beam horizontally at the block so that it refracts twice—inward upon entering the block and outward upon exiting. The vendors that provide us with lab equipment (Sargent-Welch, PASCO, Fisher Scientific, and Frey Scientific to name a few) sell acrylic blocks for this very purpose, but these are either too small or they are too expensive. If students are going to measure angles of incidence and refraction, the blocks should be larger than the typical student protractor, which has a radius of 3 in (≈ 7½ cm). These blocks are just not large enough. They are generally not thick enough either so that the beam from a typical laser passes over them and not through them. The vendors mentioned above do sell blackboard optics kits that contain, among other parts, three blocks that are large enough—on the order of 10 to 20 cm. Unfortunately, these kits cost more than $1000.
Fluoroquinolone Resistance in
Streptococcus pneumoniae
: Area Under the Concentration-Time Curve/MIC Ratio and Resistance Development with Gatifloxacin, Gemifloxacin, Levofloxacin, and Moxifloxacin
Authors: LaPlante Kerry L. , Rybak Michael J. , Tsuji Brian , Lodise Thomas P. , Kaatz Glenn W.
Published: February 2007

The potential for resistance development in
Streptococcus pneumoniae
secondary to exposure to gatifloxacin, gemifloxacin, levofloxacin, and moxifloxacin at various levels was examined at high inoculum (10
8.5
to 10
9
log
10
CFU/ml) over 96 h in an in vitro pharmacodynamic (PD) model using two fluoroquinolone-susceptible isolates. The pharmacokinetics of each drug was simulated to provide a range of free areas under the concentration-time curves (
f
AUC) that correlated with various fluoroquinolone doses. Potential first (
parC
and
parE
)- and second-step (
gyrA
and
gyrB
) mutations in isolates with raised MICs were identified by sequence analysis. PD models simulating
f
AUC/MICs of 51 and ≤60, 34 and 37, ≤82 and ≤86, and ≤24 for gatifloxacin, gemifloxacin, levofloxacin, and moxifloxacin, respectively, against each isolate were associated with first-step
parC
(S52G, S79Y, and N91D) and second-step
gyrA
(S81Y and S114G) mutations. For each fluoroquinolone a delay of first- and second-step mutations was observed with increasingly higher
f
AUC/MIC ratios and recovery of topoisomerase mutations in
S. pneumoniae
was related to the
f
AUC/MIC exposure. Clinical doses of gatifloxacin, gemifloxacin, and moxifloxacin exceeded the
f
AUC/MIC resistance breakpoint against wild-type
S. pneumoniae
, whereas those of levofloxacin (500 and 750 mg) were associated with first- and second-step mutations. The exposure breakpoints for levofloxacin were significantly different (
P
< 0.001) from those of the newer fluoroquinolones gatifloxacin, gemifloxacin, and moxifloxacin. Additionally, moxifloxacin breakpoints were significantly lower (
P
< 0.002) than those of gatifloxacin. The order of resistance development determined from
f
AUC/MIC breakpoints was levofloxacin > gatifloxacin > moxifloxacin = gemifloxacin, which may be related to structural differences within the class.
Pharmacokinetics of Saquinavir, Atazanavir, and Ritonavir in a Twice-Daily Boosted Double-Protease Inhibitor Regimen
Authors: von Hentig Nils , Müller Axel , Rottmann Carsten , Wolf Timo , Lutz Thomas , Klauke Stephan , Kurowski Michael , Oertel Bruno , Dauer Brenda , Harder Sebastian , Staszewski Schlomo
Published: February 2007

The objective of this study was to evaluate the pharmacokinetics of atazanavir (ATV), saquinavir (SQV), and ritonavir (RTV) in a boosted double-protease inhibitor (PI) therapy regimen without reverse transcriptase inhibitors (RTIs). The study design was as follows. Patients with limited RTI options received a PI combination of 300/100 mg ATV/RTV once daily and 1,000 mg SQV twice daily (group 1;n= 49) without RTI comedication. The results were compared to the plasma concentrations of PIs of patients taking either 300 mg ATV/100 mg RTV once daily plus RTIs (group 2;n= 72) or patients taking 1,000 mg SQV/100 mg RTV plus RTIs (group 3;n= 90). The study methods were as follows. Patients were given a 12/24-h pharmacokinetic assessment at steady state. Drug concentrations were measured by liquid chromatography-tandem mass spectrometry. The minimum and maximum concentrations (CminandCmax), area under the concentration-time curve under steady-state conditions (AUCss), elimination half-life, time of maximum concentration and lag time were subject to statistical analysis. The results show that patients treated with ATV/SQV/RTV exhibited significantly high SQV concentrations and moderate enhancement of the AUCssof ATV in comparison to those of patients of the control groups: for SQV in groups 1 and 3, the geometric mean (GM) of the AUCsswas 22,794 versus 15,759 ng·h/ml (GM ratio [GMR] = 1.45;P< 0.05), the GM of theCmaxwas 3,257 versus 2,331 ng/ml (GMR = 1.40;P< 0.05), and the GM of theCminwas 438 versus 437 ng/ml (GMR = 1.00); for ATV in groups 1 and 2, the GM of the AUCsswas 39,154 versus 33,626 ng·h/ml (GMR = 1.16), the GM of theCmaxwas 3,488 versus 2,924 ng/ml (GMR = 1.20), and the GM of theCminwas 515 versus 428 ng/ml (GMR = 1.21). RTV levels were comparable for all groups. A subgroup analysis detected only marginal differences in ATV plasma exposure if combined with tenofovir-disoproxilfumarate and without it. We conclude that our pharmacokinetic results support the use of a boosted double-PI regimen of ATV/SQV/RTV as a treatment option for patients who need antiretroviral therapy without RTIs.
Novel Synthetic Antimicrobial Peptides against
Streptococcus mutans
Authors: He Jian , Eckert Randal , Pharm Thanh , Simanian Maurice D. , Hu Chuhong , Yarbrough Daniel K. , Qi Fengxia , Anderson Maxwell H. , Shi Wenyuan
Published: February 2007

Streptococcus mutans
, a common oral pathogen and the causative agent of dental caries, has persisted and even thrived on the tooth surface despite constant removal and eradication efforts. In this study, we generated a number of synthetic antimicrobial peptides against this bacterium via construction and screening of several structurally diverse peptide libraries where the hydrophobicity and charge within each library was varied incrementally in order to generate a collection of peptides with different biochemical characteristics. From these libraries, we identified multiple peptides with robust killing activity against
S. mutans
. To further improve their effectiveness, the most bactericidal peptides from each library were synthesized together as one molecule, in various combinations, with and without a flexible peptide linker between each antimicrobial region. Many of these “fusion” peptides had enhanced killing activities in comparison with those of the original nonconjoined molecules. The results presented here illustrate that small libraries of biochemically constrained peptides can be used to generate antimicrobial peptides against
S. mutans
, several of which may be likely candidates for the development of anticaries agents.
EDP-420, a Bicyclolide (Bridged Bicyclic Macrolide), Is Active against
Mycobacterium avium
Authors: Bermudez Luiz E. , Motamedi Nima , Chee Christopher , Baimukanova Gyulnar , Kolonoski Peter , Inderlied Clark , Aralar Priscilla , Wang Guoqiang , Phan Ly Tam , Young Lowell S.
Published: February 2007

Infection caused by
Mycobacterium avium
complex (MAC) is common in patients with immunosuppression, such as AIDS, and deficiencies of gamma interferon and interleukin-12, as well as patients with chronic lung diseases. Treatment of MAC disease is limited since few drugs show in vivo activity. We tested a new bridged bicyclic macrolide, EDP-420, against MAC in vitro and in beige mice. EDP-420 was inhibitory in vitro at a concentration ranging from 2 to 8 μg/ml (MIC
50
of 4 μg/ml and MIC
90
of 8 μg/ml). In macrophages, EDP-420 was inhibitory at 0.5 μg/ml, suggesting that the drug concentrates intracellularly. Mice infected with macrolide-susceptible MAC strain 101 were given 100 mg of EDP-420/kg of body weight daily for 4 weeks and showed a significant reduction in the number of bacteria in both liver and spleen which was greater than the reduction observed with clarithromycin treatment at the same dose (
P
< 0.05). However, macrolide-resistant MAC 101 did not respond to EDP-420 treatment. A combination of EDP-420 with mefloquine was shown to be indifferent; mefloquine alone was active against macrolide-resistant MAC. The frequency of resistance to EDP-420 in MAC 101 was 10
−9
, which is significantly less than the emergence of resistance to clarithromycin, ∼10
−7
(
P
< 0.05). Further evaluation of EDP-420 in the treatment of MAC disease is warranted.
Efficacy of Oseltamivir Therapy in Ferrets Inoculated with Different Clades of H5N1 Influenza Virus
Authors: Govorkova Elena A. , Ilyushina Natalia A. , Boltz David A. , Douglas Alan , Yilmaz Neziha , Webster Robert G.
Published: February 2007

Highly pathogenic H5N1 influenza viruses have infected an increasing number of humans in Asia, with high mortality rates and the emergence of multiple distinguishable clades. It is not known whether antiviral drugs that are effective against contemporary human influenza viruses will be effective against systemically replicating viruses, such as these pathogens. Therefore, we evaluated the use of the neuraminidase (NA) inhibitor oseltamivir for early postexposure prophylaxis and for treatment in ferrets exposed to representatives of two clades of H5N1 virus with markedly different pathogenicities in ferrets. Ferrets were protected from lethal infection with the A/Vietnam/1203/04 (H5N1) virus by oseltamivir (5 mg/kg of body weight/day) given 4 h after virus inoculation, but higher daily doses (25 mg/kg) were required for treatment when it was initiated 24 h after virus inoculation. For the treatment of ferrets inoculated with the less pathogenic A/Turkey/15/06 (H5N1) virus, 10 mg/kg/day of oseltamivir was sufficient to reduce the lethargy of the animals, significantly inhibit inflammation in the upper respiratory tract, and block virus spread to the internal organs. Importantly, all ferrets that survived the initial infection were rechallenged with homologous virus after 21 days and were completely protected from infection. Direct sequencing of the NA or HA1 gene segments in viruses isolated from ferret after treatment showed no amino acid substitutions known to cause drug resistance in conserved residues. Thus, early oseltamivir treatment is crucial for protection against highly pathogenic H5N1 viruses and the higher dose may be needed for the treatment of more virulent viruses.
Role for Gingipains inPorphyromonas gingivalisTraffic to Phagolysosomes and Survival in Human Aortic Endothelial Cells
Authors: Yamatake Kumiko , Maeda Maki , Kadowaki Tomoko , Takii Ryosuke , Tsukuba Takayuki , Ueno Takashi , Kominami Eiki , Yokota Sadaki , Yamamoto Kenji
Published: February 2007

Gingipains are cysteine proteinases that are responsible for the virulence ofPorphyromonas gingivalis. Recent studies have shown thatP. gingivalisis trapped within autophagic compartments of infected cells, where it promotes survival. In this study we investigated the role of gingipains in the intracellular trafficking and survival of this bacterium in human aortic endothelial cells and any possible involvement of these enzymes in the autophagic pathway. Although autophagic events were enhanced by infection with either wild-type (WT)P. gingivalisstrains (ATCC 33277, 381, and W83) or an ATCC 33277 mutant lacking gingipains (KDP136), we have found that more than 90% of intracellular WT and KDP136 colocalized with cathepsin B, a lysosome marker, and only a few of the internalized cells colocalized with LC3, an autophagosome marker, during the 0.5- to 4-h postinfection period. This was further substantiated by immunogold electron microscopic analyses, thus implying thatP. gingivalisevades the autophagic pathway and instead directly traffics to the endocytic pathway to lysosomes. At the late stages after infection, WT strains in phagolysosomes retained their double-membrane structures. KDP136 in these compartments, however, lost its double-membrane structures, representing a characteristic feature of its vulnerability to rupture. Together with the ultrastructural observations, we found that the number of intracellular viable WT cells decreased more slowly than that of KDP136 cells, thus suggesting that gingipains contribute to bacterial survival, but not to trafficking, within the infected cells.