bluuebunny/crossref_metadata_2025 huggingface dataset:
Cardioprotective effects of Astragali Radix against isoproterenol‐induced myocardial injury in rats and its possible mechanism
Authors: Xu Xiao‐Le , Ji Hui , Gu Shu‐Yi , Shao Qin , Huang Qiu‐Ju , Cheng Yan‐Ping
Published: December 2007

The purpose of the present study was to investigate the effects of the Chinese medical herb Astragali Radix on myocardial injury in vivo and its possible mechanisms. Myocardial injury in rats was induced by the subcutaneous injection of a high dose of isoproterenol for 10 days, and the therapeutic effects of Astragali Radix were observed. Cardiac hemodynamics, heart coefficient and marker enzymes in serum showed that Astragali Radix prevented isoproterenol‐induced myocardial damage. Astragali Radix also improved the antioxidant status by decreasing the lipid peroxidative product malondialdehyde and increasing the activity of the antioxidant enzyme superoxide dismutase. The observed depressions in sarcoplasmic reticulum Ca2+‐ATPase mRNA and protein expression as well as Ser16‐phosphorylated phospholamban protein expression in isoproterenol‐treated rats were attenuated by Astragali Radix treatment. Moreover, treatment with Astragali Radix showed higher myocardial cAMP content compared with the isoproterenol‐alone group. These results suggest that the antioxidant property and partial prevention of changes in protein and gene expression of cardiac sarcoplasmic reticulum Ca2+ regulatory proteins which may be mediated through the cAMP pathway could help to explain the beneficial effects of Astragali Radix on myocardial injury in vivo. Copyright © 2007 John Wiley & Sons, Ltd.
Comparison of negative ion electrospray mass spectra measured by seven tandem mass analyzers towards library formation
Authors: Volná Kateřina , Holčapek Michal , Kolářová Lenka , Lemr Karel , Čáslavský Josef , Kačer Petr , Poustka Jan , Hubálek Martin
Published: December 2007

A library of negative ion electrospray ionization mass spectra and tandem mass spectra (MS/MS) of sulfonated dyes has been developed for fast identification purposes. The uniform protocol has been elaborated and applied to the measurements of more than 50 anionic dyes. Three collision energies are selected in our protocol which ensures that at least one of them provides a suitable ratio of product ions to the precursor ion. The robustness is investigated with altered values of tuning parameters (e.g. the pressure of the nebulizing gas, the temperature and the flow rate of drying gas, and the mobile phase composition). The results of the inter‐laboratory comparison of product ion mass spectra recorded on seven different tandem mass spectrometers (three ion traps, two triple quadrupoles and two hybrid quadrupole time of flight instruments) are presented for four representative anionic dyes – azo dye Acid Red 118, anthraquinone dye Acid Violet 43, triphenylmethane dye Acid Blue 1 and Al(III) metal‐complex azo dye. The fragmentation patterns are almost identical for all tandem mass analyzers, only the ratios of product ions differ somewhat which confirms the possibility of spectra transfer among different mass analyzers with the goal of library formation. Copyright © 2007 John Wiley & Sons, Ltd.
Beyond artificial integration: Reimagining cross‐racial interactions among undergraduates
Authors: Chang Mitchell J.
Published: December 2007

In this chapter, the challenges associated with engaging race and encouraging cross‐racial interactions among students are examined. Readers are invited to reimagine the role that higher education and student affairs could play in improving racial dynamics and relations among students.
The complicated realities of whiteness: From color blind to racially cognizant
Authors: Reason Robert D. , Evans Nancy J.
Published: December 2007

This chapter examines color‐blind campuses that perpetuate White transparency and racially cognizant environments that reveal and challenge notions of color blindness. Recommendations are offered to help White students respond to the realities of Whiteness and move beyond color‐blind racism.
Simulation of generation times of the rusty grain beetle, Cryptolestes ferrugineus, in farm‐stored grain in the canadian prairies, 1952‐1990
Authors: Woods S. M. , White N. D. G. , Sinha R. N.
Published: December 2007

The number of potential annual generations of the rusty grain beetle, Cryptolestes ferrugineus, was simulated in wheat stored in granaries for all crop districts in the prairie provinces of Canada each year from 1952 to 1990 using a population dynamic model driven by ecological variables. Granary size was assumed to be 6 m in diameter. Historical data for temperatures at harvest and times when storage began were used in the simulation model. A second model, which predicted the rate of temperature change at the centre of a 6‐m‐diameter bulk of wheat, determined environmental parameters for the population dynamic model. (Grain moisture content was assumed constant at 14.5% wet mass basis.) The combined model shows that the initial storage temperature is the most important factor responsible for predicting the number of generations and levels of infestation of C. ferrugineus. This finding was largely validated by historical grain storage and infestation data. For various years initial grain temperature ranged from 17.7 to 37.4 °C and harvest dates were between 1 August and 20 October. The number of generations annually in simulations based on field conditions ranged from 0.35 to 6.77 with a mean of 3.29. Three or more generations result in a severe infestation and every year at least three simulated generations were completed in some crop districts. In one year, at least three generations were completed in every crop district. Harvest temperature and date permit prediction of crop districts that will potentially have the largest populations of C. ferrugineus so that early monitoring of wheat for infestations can be targeted to areas most at risk.
Singular limits for the bi-Laplacian operator with exponential nonlinearity in $\mathbb R^{4}$
Authors: Musso Monica , Clapp Mónica , Muñoz Claudio
Published: December 2007

Let

Ω

be a bounded smooth domain in

\mathbb{R}^{4}

such that for some integer

d⩾1

its

d

-th singular cohomology group with coefficients in some field is not zero, then problem

\begin{cases}
\mathrm{\Delta }^{2}u−\rho ^{4}k(x)e^{u} = 0 & \text{in }\Omega , \\ u = \mathrm{\Delta }u = 0 & \text{on }\partial \Omega ,
\end{cases}

has a solution blowing-up, as

ρ → 0

, at

m

points of

Ω

, for any given number

m

.
Direct neurite‐osteoblastic cell communication, as demonstrated by use of an in vitro co‐culture system
Authors: Obata Koji , Furuno Tadahide , Nakanishi Mamoru , Togari Akifumi
Published: December 2007

Using an in vitro co‐culture approach comprising cultured murine superior cervical ganglia and MC3T3‐E1 osteoblast‐like cells, we found that the addition of scorpion venom (SV) elicited neurite activation via intracellular Ca2+mobilization and, after a lag period, osteoblastic Ca2+mobilization. SV did not have any direct effect on the osteoblastic cells in the absence of neurites. The addition of an α1‐adrenergic receptor (AR) antagonist, prazosin, dose‐dependently prevented the osteoblastic activation that resulted as a consequence of neural activation by SV. These results demonstrate that osteoblastic activation occurred as a direct response to neuronal activation, which activation was mediated by α1‐ARs in the osteoblastic cells.
X‐ray structure of the PHF core C‐terminus: Insight into the folding of the intrinsically disordered protein tau in Alzheimer's disease
Authors: Sevcik Jozef , Skrabana Rostislav , Dvorsky Radovan , Csokova Natalia , Iqbal Khalid , Novak Michal
Published: December 2007

The major constituent of Alzheimer's disease paired helical filaments (PHF) core is intrinsically disordered protein (IDP) tau. In spite of a considerable effort, insoluble character of PHF together with inherent physical properties of IDP tau have precluded so far reconstruction of PHF 3D structure by X‐ray crystallography or NMR spectroscopy. Here we present first crystallographic study of PHF core C‐terminus. Using monoclonal antibody MN423 specific to the tertiary structure of the PHF core, the in vivo PHF structure was imprinted into recombinant core PHF tau. Crystallization of the complex led to determination of the structure of the core PHF tau protein fragment 386TDHGAE391 at 1.65 Å resolution. Structural analysis suggests important role of the core PHF C‐terminus for PHF assembly. It is reasonable to expect that this approach will help to reveal the structural principles underlying the tau protein assembly into PHF and possibly will facilitate rationale drug design for inhibition of Alzheimer neurofibrillary changes.
Iron status markers in nonanemic pregnant women with and without iron supplementation
Authors: Ziaei Saeideh , Mehrnia Maryam , Faghihzadeh Soghrate
Published: December 2007

Objective

To measure levels of markers of anemia before and after delivery in women who had high hemoglobin levels during the early stage of the second trimester of pregnancy and did not receive iron supplementation during their pregnancies.

Methods

In a randomized, double‐blind, placebo‐controlled trial 244 women who had a hemoglobin concentration of 13.2 g/dL or greater and a serum ferritin level higher than 15 μg/L between the 13th and 18th week of pregnancy took either one 150‐mg tablet of ferrous sulfate daily or placebo during their pregnancies. Markers of anemia were measured at the time of delivery and 6 weeks postpartum.

Results

There were statistically significant differences between the 2 groups in hematocrit as well as hemoglobin and ferritin levels both at the time of delivery and 6 weeks postpartum (P < 0.05), but these differences were not clinically significant.

Conclusion

Not using iron supplementation did not cause a considerable decrease in markers of anemia in women with a hemoglobin concentration of 13.2 g/dL or greater in the second trimester of pregnancy.
The case for the epsilon symbol (ε) in RP dress
Authors: Schmitt Holger
Published: December 2007

In this article, I will argue for the use of the epsilon symbol in the lexical dress set (which includes words like step, ready, said, shelf etc.) for RP. The need for this paper arises from the fact that many, but by no means all, dictionaries and linguistic treatises employ the [ē] symbol and that this symbol is neither the most accurate nor a particularly useful one, especially for foreign learners of English. An examination of current usage and its historical rationale (or lack thereof) is followed by articulatory and perceptual evidence for the dress vowel being close to the third cardinal vowel, more practical arguments, and a discussion of the issues raised.
Liverpool English
Authors: Watson Kevin
Published: December 2007

Liverpool English (LE) is the variety of English spoken in Liverpool and much of the surrounding county of Merseyside, in the north-west of England. After London, the north-west of England is the most densely populated of all regions in England and Wales, with the population of Liverpool standing at around 450,000. LE itself is said to have developed in the middle of the 19th century, after rapid immigration from Ireland during the Irish potato famines of 1845–1847 (see Knowles 1973). Arguably as a result of this immigration, as we will see, there are some similarities between LE's phonological system and those of Irish Englishes. Of course, as we might expect, the phonological system of LE maintains its connection with other northern Englishes, too.
The origins and development of institutional welfare support in early modern Württemberg, c.1500–1700
Authors: WARDE PAUL
Published: December 2007

This article examines the development of formal poor-relief provision across the sixteenth and seventeenth centuries in rural Germany, through a case study of a district of the Duchy of Württemberg. It presents a detailed picture of practices to support the poor, whether through payments and alms from the poor chest, institutions providing credit, common rights or village and town granaries. In building up a picture of institutional practice, it also presents extensive information on the recipients of relief. It is argued that both the institutional framework and new trends in its development during the period ante-dated the Reformation, and that this society enjoyed a wide and varied capacity to support the poor that bears comparison with the English Old Poor Law. However, in a differing socio-economic context, demand for support remained more limited, and the demographic catastrophe of the Thirty Years' War arrested trends towards increasingly formalized collections, pensions and doles.
On Manin's conjecture for singular del Pezzo surfaces of degree four, II
Authors: DE LA BRETÈCHE R. , BROWNING T. D.
Published: December 2007

This paper establishes the Manin conjecture for a certain non-split singular del Pezzo surface of degree four$X \subset \bfP^4$. In fact, ifU⊂Xis the open subset formed by deleting the lines fromX, andHis the usual projective height function on$\bfP^4(\Q)$, then the height zeta function$ \sum_{x \in U(\Q)}{H(x)^{-s}} $is analytically continued to the half-plane ℜe(s) > 17/20.
Bridge numbers of torus knots
Authors: SCHULTENS JENNIFER
Published: December 2007

We provide a new self contained proof of the following result of H. Schubert: If K is a (p,q)-torus knot, then the bridge number of K is min{p, q}.
Self-gravitating stationary spherically symmetric systems in relativistic galactic dynamics
Authors: FJÄLLBORG MIKAEL , HEINZLE J. MARK , UGGLA CLAES
Published: December 2007

We study equilibrium states in relativistic galactic dynamics which are described by stationary solutions of the Einstein–Vlasov system for collisionless matter. We recast the equations into a regular three-dimensional system of autonomous first order ordinary differential equations on a bounded state space. Based on a dynamical systems analysis we derive new theorems that guarantee that the steady state solutions have finite radii and masses.
Integral bases for certain TQFT-modules of the torus
Authors: QAZAQZEH KHALED
Published: December 2007

We find two bases for the lattices of the SU(2)-TQFT-theory modules of the torus over given rings of integers. One basis is a variation on the bases defined in [GMW] for the lattices of the SO(3)-TQFT-theory modules of the torus. Moreover, we discuss the quantization functors (Vp, Zp) for p = 1, and p = 2. Then we give concrete bases for the lattices of the modules in the 2-theory. We use the above results to discuss the ideal invariant defined in [FK]. The ideal can be computed for all the 3-manifolds using the 2-theory, and for all 3-manifolds with torus boundary using the SU(2)-TQFT-theory. In fact, we show that this ideal using the SU(2)-TQFT-theory is contained in the product of the ideals using the 2-theory and the SO(3)-TQFT-theory under a certain change of coefficients, and with equality in the case of torus boundary.
Feed intake, growth rate and some anatomical characteristics of broilers fed commercial diets supplemented with green feeds
Authors: Etela I. , Kalio G.A. , Monsi A. , Ezieshi E.V.
Published: December 2007

A study was conducted on the Teaching and Research Farm of the Rivers State University of Science and Technology, Nigeria to evaluate the nutritional suitability of four treatments, namely a commercial type broiler diet as compared with the commercial diet supplemented with either fresh centrosema (Centrosema molle), pueraria (Pueraria phaseoloides), or waterleaf (Talinium triangulare) leaves. These diets were fed to 120 day-old chicks (Lohmann Brown) over a 62-day period with treatments arranged in a completely randomized design (CRD). Chemical composition of broiler basal diets differed significantly from the three green foliage supplements. Dry matter (DM) of leaf meals ranged from 97.8 to 227.0 g kg−1which was significantly (P<0.05) lower than that of broiler basal diets which averaged 900 g kg−1. Crude protein (CP) of leaf meals, however, ranged from 182.0 to 244.0 g kg−1which was generally higher than basal diets (130–153 g kg−1). Similarly, crude fiber (CF) was highest for centrosema and pueraria leaves (330–342 g kg−1) and lowest in basal diets (164–222 g kg−1). However, ether extract (EE) and nitrogen-free extract (NFE) were significantly higher in broiler basal diets. Broiler daily and total feed intake over 62 days were similar between treatments and the control, averaging 112 g d−1, while diets containing waterleaf were slightly (2.5%) lower. Total and daily bodyweight (BW) gains (2110 g and 34 g d−1) were also similar between treatments and the control, except that gains where the broiler diet was supplemented with centrosema foliage were 2.9% higher. A higher feed conversion ratio (FCR) and lower protein efficiency ratio (PER) for the diet supplemented with pueraria indicates a higher feed efficiency and better protein efficiency in the commercial control diet. Carcass characteristics with the commercial control diet included greater (P<0.05) intestinal length and gizzard and spleen weights than with green foliage supplements. However, broiler carcass weight was generally lowest (P<0.05) in the control group (64.3 g/100 g BW) and highest in the waterleaf group (71.3 g/100 g BW). Small differences in carcass weight among the treatments tested reduces the effectiveness of green feeds for practical and economic intensive broiler production. However, increased effectiveness of green feed supplementation for broiler production might likely be observed where broilers are managed on fenced rangelands planted to selected green feeds or in integrated systems where other livestock (rabbits, sheep, goats, etc.) are jointly reared. These results support the recommendation that leaf meals of green feeds should be incorporated into broiler diets in future studies.
Does use of draft animal power increase economic efficiency of smallholder farms in Kenya?
Authors: Guthiga P.M. , Karugia J.T. , Nyikal R.A.
Published: December 2007

Draft animal power (DAP) has been identified as an environmentally friendly technology that is based on renewable energy and encompasses integration of livestock and crop production systems. Draft animal technology provides farmers with a possibility to cheaply access and use manure from the draft animals and farm power needed to apply renewable practices for land intensification. Compared to motorized mechanization, DAP is viewed as an appropriate and affordable technology especially for small-scale farmers in developing countries who cannot afford the expensive fuel-powered tractor mechanization. However, it is apparent that there is no consensus among researchers on how it affects crop yields, profit and production efficiency when applied in farm operations. This study addressed the question of whether using DAP increases economic efficiency of smallholder maize producers in central Kenya. Results of the study are derived from a sample of 80 farmers, 57% of whom used draft animals while 43% used hand hoes in carrying farm operations. In the study area, draft animals are almost exclusively used for land preparation and planting, with very few farmers applying them in the consecutive operations such as weeding. A profit function was estimated to test the hypothesis of equal economic efficiency between ‘DAP’ and ‘hoe’ farms. The results showed that farmers who used DAP obtained higher yields and operated at a higher economic efficiency compared to those who used hand hoes. The analysis underscores the viability of DAP in increasing profitability of small-scale farms; however, other aspects of the technology, such as affordability of the whole DAP package, availability of appropriate implements and skills of using the technology, must be taken into account when promoting adoption of DAP technology.
Organic banana production in Ecuador: Its implications on black Sigatoka development and plant–soil nutritional status
Authors: Jimenez Maria , Van der Veken Lieselot , Neirynck Heleen , Rodríguez Helga , Ruiz Omar , Swennen Rony
Published: December 2007

Black Sigatoka, caused by the leaf fungus Mycosphaerella fijiensis Morelet, is a major constraint to banana production around the world. In Ecuador, the biggest banana-exporting country in the world, this disease has become increasingly aggressive. This has resulted in more fungicide applications, which have significantly increased costs in production and for the environment. Consequently, many banana growers have shifted to organic production, which produces greater economic returns as a result of higher sale prices. In addition, production costs are lower as no fungicides are applied. These organic bananas receive substantial amounts of organic products. This study describes the black Sigatoka disease and nutrient status in an organic banana plantation and compares it with a conventionally fertilized and fungicide-treated plantation. Black Sigatoka symptoms were evaluated in the vegetative and flowering stages under both production conditions and in vitro conditions. Univariate and multivariate descriptive statistics were used to analyze the parameters. Disease symptoms were more severe in leaves from the organic field than in leaves from the inorganic field, but the nutrient status (soil and foliar) did not differ between the two farms. Banana plants from the organic farm had 12 functional leaves at flowering and eight functional leaves at harvest. Average banana yields were over 40% lower for organic versus inorganic management; however, the average price received for organic bananas was over two times higher. Profit–cost analysis has shown that the organic banana farm was substantially more profitable than the inorganic one during the time period analyzed. These results indicated that bananas can be grown commercially without fungicides, and the lower productivity levels are compensated by higher prices of organic fruits in international markets. In addition, organic production has beneficial impacts on social and environmental issues.
Incidence of Responses at the Lower Audiometric Limits
Authors: Halpin Chris
Published: December 2007

Purpose

To put forward a symbol extension, consisting of an upward arrow added to current symbols, to denote that a patient continued to respond at the audiometric limit (i.e., –10 dB HL). Also, to present survey data to characterize the incidence of these responses.

Method

A retrospective survey of 2,821 sequential audiometric evaluations was performed. Responses at the audiometric limits were counted, along with the stimulus conditions (i.e., transducer, frequency, and masking) and the age of the patient.

Results

A total of 307 instances of responses at the lower audiometric limits were seen in 173 of these cases (6.13%), with the majority by bone conduction.

Conclusions

The overall rate of responses at the audiometric limits was low, as expected. However, these responses were primarily seen in the age group from 4 to 15 years, and at least one such response occurred in 26% of cases in that age range.
The Association Between Tinnitus and Posttraumatic Stress Disorder
Authors: Fagelson Marc A.
Published: December 2007

Purpose

Posttraumatic stress disorder (PTSD) affects nearly 10% of the population, a prevalence comparable with that of tinnitus. Similarities between the way PTSD and tinnitus influence auditory behaviors include exaggerated startle responses and decreased loudness tolerance. Tinnitus loudness is often exacerbated by sounds that trigger PTSD-related anxiety. This report addresses physical and psychological relations between PTSD and tinnitus.

Method

A chart review of veterans seen over a 4-year period for tinnitus services was conducted. Case history and self-assessments of tinnitus handicap were examined in all patients. A review of the literature related to triggers and effects of PTSD was conducted to explore potential consequences related to the presence of PTSD in the Veterans Affairs Medical Center (VAMC) tinnitus population.

Results

Chart review confirmed that 34% of the first 300 patients enrolled in the VAMC Tinnitus Clinic also carried a diagnosis of PTSD. Patient reports citing tinnitus severity, suddenness of tinnitus onset, sound-tolerance problems, and sound-triggered exacerbation of tinnitus were more common for patients with a PTSD diagnosis than patients with tinnitus only.

Conclusions

Several neural mechanisms linked to both tinnitus and PTSD affect auditory behaviors. Audiologists should be aware that patients with tinnitus and PTSD will require test protocols and referrals that address these powerful responses.
Objective and Subjective Hearing Aid Assessment Outcomes
Authors: Mendel Lisa Lucks
Published: December 2007

Purpose

To determine whether specific sentence recognition assessments were sensitive enough to serve as objective outcome measurements that document subjective improvements in speech understanding with hearing aids.

Method

The Revised Speech Perception in Noise test (R-SPIN; R. C. Bilger, J. M. Nuetzel, W. M. Rabinowitz, & C. Rzeczkowski, 1984), the Hearing in Noise Test (HINT; M. Nilsson, S. D. Soli, & J. A. Sullivan, 1994), and the Quick Speech-in-Noise test (QuickSIN; Etymotic Research, 2001; M. C. Killion, P. A. Niquette, G. I. Gudmundsen, L. J. Revit, & S. Banerjee, 2004) were administered to 21 hearing aid users to determine whether the tests could adequately document improvements in speech understanding with hearing aids compared with the research participants' self-assessments of their own performance. Comparisons were made between unaided and aided performance on these sentence tests and on the Hearing Aid Performance Inventory (HAPI; B. E. Walden, M. Demorest, & E. Hepler, 1984).

Results

The R-SPIN, the HINT Quiet threshold, and the QuickSIN signal-to-noise ratio (SNR) loss were the most sensitive of the sentence recognition tests to objectively assess improvements in speech perception performance with hearing aids. Comparisons among the subjective and objective outcome measures documented that HAPI ratings improved as performance on the R-SPIN, the HINT Quiet threshold, and the QuickSIN SNR loss improved.

Conclusions

Objective documentation of subjective impressions is essential for determining the efficacy of treatment outcomes in hearing aid fitting. The findings reported here more clearly define the relationship between objective and subjective outcome measures in an attempt to better define true hearing aid benefit.
Directional Benefit in Simulated Classroom Environments
Authors: Ricketts Todd , Galster Jason , Tharpe Anne Marie
Published: December 2007

Purpose

To examine speech recognition performance and subjective ratings for directional and omnidirectional microphone modes across a variety of simulated classroom environments.

Method

Speech recognition was measured in a group of 26 children age 10–17 years in up to 8 listening environments.

Results

Significant directional benefit was found when the sound source(s) of interest was in front, and directional decrement was measured when the sound source of interest was behind the participants. Of considerable interest is that a directional decrement was observed in the absence of directional benefit when sources of interest were both in front of and behind the participants. In addition, limiting directional processing to the low frequencies eliminated both the directional deficit and the directional advantage.

Conclusions

Although these data support the use of directional hearing aids in some noisy school environments, they also suggest that use of the directional mode should be limited to situations in which all talkers of interest are located in the front hemisphere. These results highlight the importance of appropriate switching between microphone modes in the school-age population.
Contribution of High-Frequency Information to the Acceptance of Background Noise in Listeners With Normal and Impaired Hearing
Authors: Plyler Patrick N. , Madix Steven G. , Thelin James W. , Johnston Kristie W.
Published: December 2007

Purpose

To determine whether information beyond 2.0 kHz affected the acceptance of background noise in listeners with normal and/or impaired hearing.

Method

Speech stimuli (Arizona Travelogue) and multitalker babble were low-pass filtered at cutoff frequencies of 2.0, 4.0, and 6.0 kHz and presented using an adaptive paradigm to determine the most comfortable level (MCL) and acceptable noise level (ANL) for 4 experimental conditions (unfiltered, 2.0, 4.0, and 6.0 kHz) for each listener.

Results

MCL for listening to speech in quiet was significantly increased when the speech stimuli were low-pass filtered at 2.0 kHz relative to the unfiltered and 6.0-kHz conditions. Acceptance of background noise was significantly poorer when the speech and noise stimuli were low-pass filtered at 2.0 kHz relative to the 6.0-kHz condition. Listeners with impaired hearing sensitivity had significantly greater MCL values than listeners with normal hearing, but ANL values were not significantly affected by the hearing sensitivity of the listener.

Conclusions

Information beyond 2.0 kHz significantly affected MCL and ANL values in both listeners with normal hearing and impaired hearing; however, effects for both the MCL and ANL measurements were small and may not be significant clinically.
Effectiveness of “Dangerous Decibels,” a School-Based Hearing Loss Prevention Program
Authors: Griest Susan E. , Folmer Robert L. , Martin William Hal
Published: December 2007

Purpose

To evaluate the effectiveness of the “Dangerous Decibels” educational program in increasing students' knowledgeandpositively changing their attitudes and intended behaviors related to hearing and hearing loss prevention.

Method

Baseline questionnaires were completed by 478 4th-grade students and 550 7th-grade students. Approximately half of the students in each grade received a 35-min interactive classroom presentation on hearing and hearing loss prevention. The remaining students served as comparison groups. Students who received the curriculum filled out questionnaires immediately after the presentation. All students filled out follow-up questionnaires 3 months after baseline.

Results

Fourth-grade students who participated in the Dangerous Decibels presentation exhibited significant improvements in knowledge and attitudes related to hearing and hearing loss prevention. These improvements were maintained 3 months after the presentation. Seventh-grade students also experienced long-term improvements in their knowledge base. However, attitudes and intended behaviors in 7th graders returned to baseline levels 3 months postpresentation.

Conclusion

The Dangerous Decibels hearing loss prevention program was effective at producing long-term improvements in the knowledge base of 4th- and 7th-grade students. Future studies should include components on peer pressure and should incorporate repeated, multimodality interventions to increase the likelihood of long-term improvement in adolescents.
Stern-Volmer modeling of steady-state Förster energy transfer between dilute, freely diffusing membrane-bound fluorophores
Authors: Buboltz Jeffrey T. , Bwalya Charles , Reyes Santiago , Kamburov Dobromir
Published: December 2007

Two different metrics are used to assess Förster resonance energy transfer (FRET) between fluorophores in the steady state: (i) acceptor-quenching of donor fluorescence E (also known as transfer efficiency) and (ii) donor-excited acceptor fluorescence FADex. While E is still more widely used, FADex has been gaining in popularity for practical reasons among experimentalists who study biomembranes. Here, for the special case of membrane-bound fluorophores, we present a substantial body of experimental evidence that justifies the use of simple Stern-Volmer expressions when modeling either FRET metric under dilute-probe conditions. We have also discovered a dilute-regime correspondence between our Stern-Volmer expression for E and Wolber and Hudson’s series approximation for steady-state Förster quenching in two dimensions (2D). This novel correspondence allows us to interpret each of our 2D quenching constants in terms of both (i) an effective Förster distance and (ii) two maximum acceptor-concentration limits, each of which defines its own useful experimental regime. Taken together, our results suggest a three-step strategy toward designing more effective steady-state FRET experiments for the study of biomembranes.
Nanostructured ceramics by electrospinning
Authors: Ramaseshan Ramakrishnan , Sundarrajan Subramanian , Jose Rajan , Ramakrishna S.
Published: December 2007

Nanostructured ceramics are attractive materials that find potential uses ranging from simple everyday applications like paints and pigments to sophisticated ones such as bioimaging, sensors, etc. The inability to economically synthesize nanoscale ceramic structures in a large scale and simultaneously achieve precise control of their size has restricted their real time application. Electrospinning is an efficient process that can fabricate nanofibers on an industrial scale. During the last 5 years, there has been remarkable progress in applying this process to the fabrication of ceramic nanorods and nanofibers. Ceramic nanofibers are becoming useful and niche materials in several applications owing to their surface dependant and size dependant properties. These advances are reviewed here. The various ceramic nanofiber systems that have been fabricated so far are presented. The physical and chemical property enhancements due to the nanosize have been discussed in detail and the various applications they fit into are outlined in this article.
Ferroelectric polymer gate on AlGaN∕GaN heterostructures
Authors: Malin L. , Stolichnov I. , Setter N.
Published: December 2007

There has been much investigation into the implementation of field effect transistors; however, a commercial device is still not available. An attempt is made here to develop a ferroelectric gate device using an Al0.3Ga0.7N∕GaN heterostructure with a two dimensional electron gas (2DEG). The ferroelectric copolymer poly(vinylidene fluoride∕trifluoroethylene) [P(VDF∕TrFE)] was chosen as a gate material due to advantages such as its small dielectric constant and low crystallization temperature in comparison with the perovskite ferroelectrics. A P(VDF∕TrFE) layer was successfully deposited onto an Al0.3Ga0.7N∕GaN heterostructure without degrading the transport properties of the 2DEG. The polarization reversal in the gate was proved by piezoelectric scanning force microscopy. With this structure, it was possible to demonstrate the ferroelectric gate operation when modulating the transport properties of the 2DEG due to the stable reversal of the spontaneous polarization in the gate. Transport measurements in combination with piezoelectric scanning probe microscopy enable an insight into the physical origin of the retention loss in the system.
Hydrogen annealing of arrays of planar and vertically stacked Si nanowires
Authors: Dornel E. , Ernst T. , Barbé J. C. , Hartmann J. M. , Delaye V. , Aussenac F. , Vizioz C. , Borel S. , Maffini-Alvaro V. , Isheden C. , Foucher J.
Published: December 2007

Four level matrices of round, 35nm in diameter Si nanowires (NWs) are obtained thanks to a top-down approach. In particular, we report optimized H2 annealing conditions (800to900°C) in order to reconstruct the plasma-etched surfaces of the suspended nanowires. The nanowire shape evolution has been studied in scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. The side roughness decrease and the rounding of the NWs have been quantified. The instability of the anchors of the NWs to the contact regions has been evidenced and confirmed by surface diffusion simulations.
Epitaxial stabilization and structural properties of REMnO3 (RE=Dy,Gd,Sm) compounds in a layered, hexagonal ABO3 structure
Authors: Balasubramaniam K. R. , Havelia S. , Salvador P. A. , Zheng H. , Mitchell J. F.
Published: December 2007

RE Mn O 3  (RE=Dy,Gd,Sm) films were deposited on (110) surfaces of single crystalline hexagonal (h-)YMnO3. These films adopted the metastable multiferroic h-REMnO3 structure instead of the stable perovskite structure. Sharp (hh0) diffraction peaks with narrow rocking curves were found for all films. The peak widths increased with increasing size of the rare-earth cation. The c-axis/a-axis lattice parameter decreased/increased monotonically with increasing rare-earth size for these epitaxial films. All films exhibited the following epitaxial relationship {110}REMnO3‖{110}YMnO3;⟨11¯0⟩REMnO3‖⟨11¯0⟩YMnO3. The single-phase hexagonal films were kinetically robust against back transformation to the stable perovskite structure even to thicknesses of 50nm.
ac and dc electro-optical response of planar aligned liquid crystal cells
Authors: Ciuchi F. , Mazzulla A. , Pane A. , Adrian Reyes J.
Published: December 2007

Interaction of static electric fields with a nematic is complicated because of the presence of charges, which originates from aligning layers or from molecular breakdown, affecting the electro-optic response of a liquid crystal cell. We analyze the aligning layers effect on the electro-optical response and develop a model based on a description of the ion balance on the conducting plates taking into account both drift current and saturation effects due to the ion migration inside the cell, neglecting diffusion current. The model well agrees with data for low voltages, while for higher ones, diffusion current should be taken into account.
Low nonalloyed Ohmic contact resistance to nitride high electron mobility transistors using N-face growth
Authors: Wong Man Hoi , Pei Yi , Palacios Tomás , Shen Likun , Chakraborty Arpan , McCarthy Lee S. , Keller Stacia , DenBaars Steven P. , Speck James S. , Mishra Umesh K.
Published: December 2007

Nonalloyed Ohmic contacts on Ga-face n+-GaN∕AlGaN∕GaN high electron mobility transistor (HEMT) structures typically have significant contact resistance to the two-dimensional electron gas (2DEG) due to the AlGaN barrier. By growing the HEMT structure inverted on the N-face, electrons from the contacts were able to access the 2DEG without going through an AlGaN layer. A low contact resistance of 0.16Ωmm and specific contact resistivity of 5.5×10−7Ωcm2 were achieved without contact annealing on the inverted HEMT structure.
Multidimensional ZnO light-emitting diode structures grown by metal organic chemical vapor deposition on p-Si
Authors: Kim Dong Chan , Han Won Suk , Cho Hyung Koun , Kong Bo Hyun , Kim Hyoung Sub
Published: December 2007

A multidimensional ZnO light-emitting diode (LED) structure comprising film/nanorods/substrate was fabricated on a p-type Si substrate using metal organic chemical vapor deposition at relatively low growth temperature. The filmlike top layer used for the metal contact was continuously formed on the ZnO nanorods by varying the growth conditions and the resulting structure allowed us to utilize the nanorods with intense emission as an active layer. We investigated the performance of the resulting multidimensional LED. An extremely high breakdown voltage and low reverse leakage current as well as typical rectification behavior were observed in the I-V characteristics.
Trace gas detection using nanostructured graphite layers
Authors: Qazi Muhammad , Vogt Thomas , Koley Goutam
Published: December 2007

Nanostructured graphite (NG) has been investigated as a sensing material using a highly sensitive potentiometric detection technique. NO2 concentration down to 60ppb was detected in ambient conditions using NG functionalization layer. Simultaneous current and surface work function (SWF) change transients measured using NG functionalization layer reveal much shorter response time for the later, which is attributed to its dependence solely on surface molecular adsorption. The gradient of SWF with respect to the current transient was found to be independent of gaseous concentration and fraction of preoccupied surface states.
A highly efficient wide-band-gap host material for blue electrophosphorescent light-emitting devices
Authors: Whang Dong Ryeol , You Youngmin , Kim Se Hun , Jeong Won-Ik , Park Young-Seo , Kim Jang-Joo , Park Soo Young
Published: December 2007

We report on an efficient wide-band-gap host material for blue electrophosphorescence devices, namely, 1,2-trans-di-9-carbazolylcyclobutane (DCz). Photophysical studies show that lower-energy excimer formation between the carbazole units can be efficiently suppressed in a DCz film, thus maintaining its high triplet-state energy and inducing an exothermic energy transfer from DCz to iridium(III)bis[(4,6-difluorophenyl)-pyridinato-N,C2′]picolinate (FIrpic). Electrophosphorescent devices comprising a FIrpic:DCz emitting layer exhibit a superior performance with a maximum external quantum efficiency of 9.8%, a maximum luminance efficiency of 21.5cd∕A, and a maximum power efficiency of 15.0lm∕W at 0.01mA∕cm2.
Hyperpolarized
13
C allows a direct measure of flux through a single enzyme-catalyzed step by NMR
Authors: Merritt Matthew E. , Harrison Crystal , Storey Charles , Jeffrey F. Mark , Sherry A. Dean , Malloy Craig R.
Published: December 2007

13
C NMR is a powerful tool for monitoring metabolic fluxes
in vivo
. The recent availability of automated dynamic nuclear polarization equipment for hyperpolarizing
13
C nuclei now offers the potential to measure metabolic fluxes through select enzyme-catalyzed steps with substantially improved sensitivity. Here, we investigated the metabolism of hyperpolarized [1-
13
C
1
]pyruvate in a widely used model for physiology and pharmacology, the perfused rat heart. Dissolved
13
CO
2
, the immediate product of the first step of the reaction catalyzed by pyruvate dehydrogenase, was observed with a temporal resolution of ≈1 s along with H
13
CO
3
−
, the hydrated form of
13
CO
2
generated catalytically by carbonic anhydrase. In hearts presented with the medium-chain fatty acid octanoate in addition to hyperpolarized [1-
13
C
1
]pyruvate, production of
13
CO
2
and H
13
CO
3
−
was suppressed by ≈90%, whereas the signal from [1-
13
C
1
]lactate was enhanced. In separate experiments, it was shown that O
2
consumption and tricarboxylic acid (TCA) cycle flux were unchanged in the presence of added octanoate. Thus, the rate of appearance of
13
CO
2
and H
13
CO
3
−
from [1-
13
C
1
]pyruvate does not reflect production of CO
2
in the TCA cycle but rather reflects flux through pyruvate dehydrogenase exclusively.
A role for the inositol kinase Ipk1 in ciliary beating and length maintenance
Authors: Sarmah Bhaskarjyoti , Winfrey Virginia P. , Olson Gary E. , Appel Bruce , Wente Susan R.
Published: December 2007

Cilia project from cells as membranous extensions, with microtubule structural cores assembling from basal bodies by intraflagellar transport (IFT). Here, we report a ciliary role for the inositol 1,3,4,5,6-pentakisphosphate 2-kinase (Ipk1) that generates inositol hexakisphosphate. In zebrafish embryos, reducing Ipk1 levels inhibited ciliary beating in Kupffer's vesicle and decreased ciliary length in the spinal canal, pronephric ducts, and Kupffer's vesicle. Electron microscopy showed that ciliary axonemal structures were not grossly altered. However, coincident knockdown of Ipk1 and IFT88 or IFT57 had synergistic perturbations. With GFP-Ipk1 enriched in centrosomes and basal bodies, we propose that Ipk1 plays a previously uncharacterized role in ciliary function.
The origin of islet-like cells in
Drosophila
identifies parallels to the vertebrate endocrine axis
Authors: Wang Shu , Tulina Natalia , Carlin Daniel L. , Rulifson Eric J.
Published: December 2007

Single-cell resolution lineage information is a critical key to understanding how the states of gene regulatory networks respond to cell interactions and thereby establish distinct cell fates. Here, we identify a single pair of neural stem cells (neuroblasts) as progenitors of the brain insulin-producing neurosecretory cells of
Drosophila
, which are homologous to islet β cells. Likewise, we identify a second pair of neuroblasts as progenitors of the neurosecretory
Corpora cardiaca
cells, which are homologous to the glucagon-secreting islet α cells. We find that both progenitors originate as neighboring cells from anterior neuroectoderm, which expresses genes orthologous to those expressed in the vertebrate adenohypophyseal placode, the source of endocrine anterior pituitary and neurosecretory hypothalamic cells [Whitlock KE (2005)
Trends Endocrinol Metab
16:145–151]. This ontogenic-molecular concordance suggests that a rudimentary brain endocrine axis was present in the common ancestor of humans and flies, where it orchestrated the islet-like endocrine functions of insulin and glucagon biology.
Trafficking-dependent phosphorylation of Kv1.2 regulates voltage-gated potassium channel cell surface expression
Authors: Yang Jae-Won , Vacher Helene , Park Kang-Sik , Clark Eliana , Trimmer James S.
Published: December 2007

Kv1.2 α-subunits are components of low-threshold, rapidly activating voltage-gated potassium (Kv) channels in mammalian neurons. Expression and localization of Kv channels is regulated by trafficking signals encoded in their primary structure. Kv1.2 is unique in lacking strong trafficking signals and in exhibiting dramatic cell-specific differences in trafficking, which is suggestive of conditional trafficking signals. Here we show that a cluster of cytoplasmic C-terminal phosphorylation sites regulates Kv1.2 trafficking. Using tandem MS to analyze Kv1.2 purified from rat, human, and mouse brain, we identified in each sample
in vivo
phosphoserine (pS) phosphorylation sites at pS434, pS440, and pS441, as well as doubly phosphorylated pS440/pS441. We also found these sites, as well as pS449, on recombinant Kv1.2 expressed in heterologous cells. We found that phosphorylation at pS440/pS441 is present only on the post-endoplasmic reticulum (ER)/cell surface pool of Kv1.2 and is not detectable on newly synthesized and ER-localized Kv1.2, on which we did observe pS449 phosphorylation. Elimination of PS440/PS441 phosphorylation by mutation reduces cell-surface expression efficiency and functional expression of homomeric Kv1.2 channels. Interestingly, mutation of S449 reduces phosphorylation at pS440/pS441 and also decreases Kv1.2 cell-surface expression efficiency and functional expression. These mutations also suppress trafficking of Kv1.2/Kv1.4 heteromeric channels, suggesting that incorporation of Kv1.2 into heteromeric complexes confers conditional phosphorylation-dependent trafficking to diverse Kv channel complexes. These data support Kv1.2 phosphorylation at these clustered C-terminal sites as playing an important role in regulating trafficking of Kv1.2-containing Kv channels.
A structural basis for enhancement of long-term associative memory in single dendritic spines regulated by PKC
Authors: Hongpaisan Jarin , Alkon Daniel L.
Published: December 2007

Using both scanning confocal and electron microscopic morphometric measurements, we analyzed single dendritic spines of CA1 pyramidal cells in the hippocampi of water maze-trained rats vs. controls. Two days after completion of all training, we observed a memory-specific increase in the number of mushroom spines—all of which make synaptic contacts—but not in the numbers of filopodia or stubby or thin spines, as quantified with double-blind protocols in both scanning confocal and electron microscopic images. This memory-specific increase of mushroom spine number was enhanced by the PKC activator and candidate Alzheimer's disease therapeutic bryostatin, blocked by the PKCα-isozyme blocker Ro 31-8220, and accompanied by increases in the number of “perforated” postsynaptic densities, increased numbers of presynaptic vesicles, and the increased occurrence of double-synapse presynaptic boutons associated with the mushroom spines. These and other confocally imaged immunohistochemical results described here involving PKC substrates indicate that individual mushroom spines provide structural storage sites for long-term associative memory and sites for memory-specific synaptogenesis that involve PKC-regulated changes of spine shape, as well as PKC-regulated changes of pre- and postsynaptic ultrastructure.