bluuebunny/crossref_metadata_2025 huggingface dataset:
Computing the discriminants of Brauer’s centralizer algebras
Authors: Hanlon Phil , Wales David
Published: June 2010

This paper discusses a computational problem arising in the study of the structure theory of Brauer’s orthogonal and symplectic centralizer algebras. The problem is to compute the ranks of certain combinatorially defined matrices

Z

m
,
k

(
x
)

{Z_{m,k}}(x)

(these matrices are presented in

§
2

\S 2

). This computation is difficult because the sizes of the matrices

Z

m
,
k

(
x
)

{Z_{m,k}}(x)

are enormous even for small values of m and k. However, there is a great deal of symmetry amongst the entries of the matrices. In this paper we show how to design algorithms that take full advantage of this symmetry, using the representation theory of the symmetric groups. We also present data collected using these algorithms and a number of conjectures about the centralizer algebras.
The computation of sextic fields with a quadratic subfield
Authors: Bergé A.-M. , Martinet J. , Olivier M.
Published: June 2010

We describe four tables (one for each signature) of sixth-degree fields K containing a quadratic subfield k. The tables contain various information, including, for each possible discriminant

d
K

{d_K}

of K, a cubic polynomial which defines K/k, the discriminant of the quartic field

k
~

\tilde k

such that

k
~

/

k

\tilde k/k

is the quadratic extension corresponding to K/k, and the Galois group of the Galois closure

N

/

Q

N/\mathbb {Q}

of

K

/

Q

K/\mathbb {Q}

.
Some new polyhedra with vertex degree 4 and/or 5 only
Authors: Duijvestijn A. J. W. , Helthuis B.
Published: June 2010

A table of 4- and 5-hedra of orders up to and including 22 is given.
Finite element interpolation of nonsmooth functions satisfying boundary conditions
Authors: Scott L. Ridgway , Zhang Shangyou
Published: June 2010

In this paper, we propose a modified Lagrange type interpolation operator to approximate functions in Sobolev spaces by continuous piecewise polynomials. In order to define interpolators for "rough" functions and to preserve piecewise polynomial boundary conditions, the approximated functions are averaged appropriately either on d- or

(
d
−
1
)

(d - 1)

-simplices to generate nodal values for the interpolation operator. This combination of averaging and interpolation is shown to be a projection, and optimal error estimates are proved for the projection error.
Symmetrizable finite difference operators
Authors: Wade Bruce A.
Published: June 2010

We introduce the notion of a symmetrizable finite difference operator and prove that such operators are stable. We then present some sufficient conditions for symmetrizability. One of these extends H.-O. Kreiss’ theorem on dissipative difference schemes for hyperbolic equations to a more general case with full (x, t)-variable coefficients.
The optimum addition of points to quadrature formulae
Authors: Patterson T. N. L.
Published: June 2010

Methods are developed for the addition of points in an optimum manner to the Gauss, Lobatto and general quadrature formulae. A new set of

n
n

-point formulae are derived of degree

(
3
n
−
1
)

/

2

(3n - 1)/2

.
The application of linear multistep methods to singular initial value problems
Authors: de Hoog Frank R. , Richard Weiss
Published: June 2010

A theory for linear multistep schemes applied to the initial value problem for a nonlinear first order system of differential equations with a singularity of the first kind is developed. Predictor-corrector schemes are also considered. The specific examples given are systems derived from partial differential equations in the presence of symmetry.
The HOG Pathway Dictates the Short-Term Translational Response after Hyperosmotic Shock
Authors: Warringer Jonas , Hult Malin , Regot Sergi , Posas Francesc , Sunnerhagen Per
Published: June 2010

Cellular responses to environmental changes occur on different levels. We investigated the translational response of yeast cells after mild hyperosmotic shock by isolating mRNA associated with multiple ribosomes (polysomes) followed by array analysis. Globally, recruitment of preexisting mRNAs to ribosomes (translational response) is faster than the transcriptional response. Specific functional groups of mRNAs are recruited to ribosomes without any corresponding increase in total mRNA. Among mRNAs under strong translational up-regulation upon shock, transcripts encoding membrane-bound proteins including hexose transporters were enriched. Similarly, numerous mRNAs encoding cytoplasmic ribosomal proteins run counter to the overall trend of down-regulation and are instead translationally mobilized late in the response. Surprisingly, certain transcriptionally induced mRNAs were excluded from ribosomal association after shock. Importantly, we verify, using constructs with intact 5′ and 3′ untranslated regions, that the observed changes in polysomal mRNA are reflected in protein levels, including cases with only translational up-regulation. Interestingly, the translational regulation of the most highly osmostress-regulated mRNAs was more strongly dependent on the stress-activated protein kinases Hog1 and Rck2 than the transcriptional regulation. Our results show the importance of translational control for fine tuning of the adaptive responses.
Vitiligo following intense pulsed light treatment
Authors: SHIN Jung U , ROH Mi Ryung , LEE Ju Hee
Published: June 2010

Vitiligo is an acquired depigmenting disorder characterized by the progressive loss of melanocytes from the epidermis and epidermal appendages, which results in milky‐white macular lesions. Various factors are suspected to affect the induction and progression of vitiligo such as emotional shock, sunburn, pregnancy, physical illness and trauma. The intense pulsed light (IPL) device which mostly affects redness and dyspigmentation has a broad spectrum of emissions of white light with wavelengths between approximately 515 and 1200 nm. Adverse effects such as purpura and pigmentary changes are known to be rare. We present a 41‐year‐old woman who developed multiple round, hypopigmented macules on both the cheek and mandibular area following the treatment with IPL for lentigines and dyspigmentation. Based on biopsy and Wood’s lamp examination, diagnosis as vitiligo was made. She was treated with a 308‐nm excimer laser. After 3 months of treatment, almost complete repigmentation was seen but another coin‐sized hypopigmented patch was noted after 5 months later. Herein, we report a case of vitiligo which developed after IPL treatment. This is the first case to be reported which vitiligo developed after IPL treatment. Therefore, dermatologists should be aware of unsighted vitiligo lesion before IPL treatment.
Expression of sweet pepper Hrap gene in banana enhances resistance to Xanthomonas campestris pv. musacearum
Authors: TRIPATHI LEENA , MWAKA HENRY , TRIPATHI JAINDRA NATH , TUSHEMEREIRWE WILBERFORCE KATEERA
Published: June 2010

Banana Xanthomonas wilt (BXW), caused by the bacterium Xanthomonas campestris pv. musacearum, is the most devastating disease of banana in the Great Lakes region of Africa. The pathogen's rapid spread has threatened the livelihood of millions of Africans who rely on banana fruit for food security and income. The disease is very destructive, infecting all banana varieties, including both East African Highland bananas and exotic types of banana. In the absence of natural host plant resistance among banana cultivars, the constitutive expression of the hypersensitivity response‐assisting protein (Hrap) gene from sweet pepper (Capsicum annuum) was evaluated for its ability to confer resistance to BXW. Transgenic lines expressing the Hrap gene under the regulation of the constitutive CaMV35S promoter were generated using embryogenic cell suspensions of two banana cultivars: ‘Sukali Ndiizi’ and ‘Mpologoma’. These lines were characterized by molecular analysis, and were challenged with Xanthomonas campestris pv. musacearum to analyse the efficacy of the Hrap gene against BXW. The majority of transgenic lines (six of eight) expressing Hrap did not show any symptoms of infection after artificial inoculation of potted plants in the screenhouse, whereas control nontransgenic plants showed severe symptoms resulting in complete wilting. This study demonstrates that the constitutive expression of the sweet pepper Hrap gene in banana results in enhanced resistance to BXW. We describe the development of transgenic banana varieties resistant to BXW, which will boost the arsenal available to fight this epidemic disease and save livelihoods in the Great Lakes region of East and Central Africa.
Variability of thromboelastographic responses following the administration of rFVIIa to haemophilia A dogs supports the individualization of therapy with a global test of haemostasis
Authors: OTHMAN M. , POWELL S. , HOPMAN W. M , LILLICRAP D.
Published: June 2010

Summary.  The efficacy of recombinant factor VIIa (rFVIIa) therapy in haemophilia A is challenged by the lack of a reliable monitoring tool for treatment response. This is further complicated by the significant inter‐patient variability associated with this response. Thromboelastography (TEG), a real time global haemostatic test has shown superiority over conventional tests of haemostasis and has proven efficiency in the monitoring of bypass agents such as rFVIIa and FEIBA™. However, this evaluation has been limited to a few case studies or very small patient series. In this study, six severe haemophilia A dogs were treated with a clinically relevant single dose of rFVIIa, and therapy was monitored by thromboelastography predrug and at 15, 30 and 60 min postdrug administration using citrated whole blood samples activated with tissue factor and compared with non‐tissue factor‐activated samples. Despite the homogeneity of the tested dogs, a clear inter‐individual variation was observed in the pre‐and post‐rFVIIa Thromboelastography analyzes. The improvement of global haemostatic parameters was seen as early as 15 min following drug administration, with a peak for factor VIIa activity in plasma at the same time. There is a significant correlation between plasma FVIIa and TEG parameters 15 min postinjection, and the baseline TEG profile influences the individual postdrug administration outcome. Together, these data support the value of TEG not only as an effective monitoring haemostatic test, but also as a tool for individualization of therapy to achieve the best haemostatic and cost effectiveness of rFVIIa therapy.
Identification of a functional luciferase gene in the non‐luminous diurnal firefly, Lucidina biplagiata
Authors: Oba Y. , Furuhashi M. , Inouye S.
Published: June 2010

We isolated a luciferase gene (LbLuc) from the non‐luminous diurnal firefly, Lucidina biplagiata, with high similarity to that from the nocturnal firefly, Photinus pyralis. The recombinant LbLuc showed luminescence activity comparable to that of the luciferases from P. pyralis and Luciola cruciata. To understand the non‐luminosity of L. biplagiata, we determined the amount of luciferase in the adult specimen using the luciferin–luciferase reaction and found that the content of luciferase in L. biplagiata was estimated to be only 0.1% of that in L. cruciata. As previously reported, the content of luciferin in L. biplagiata was less than 0.1% of that in L. cruciata. Thus, the non‐luminosity of L. biplagiata might be explained by low levels of both luciferase and luciferin.
Organismal traits are more important than environment for species interactions in the intertidal zone
Authors: Wood Spencer A. , Lilley Stacie A. , Schiel David R. , Shurin Jonathan B.
Published: June 2010

Ecology Letters (2010) 13: 1160–1171

Species interactions come in a variety of forms, from weak to strong, and negative or positive, each with unique consequences for local community structure. However, interactions depend on several biotic, abiotic and scale‐dependent variables that make their magnitude and direction difficult to predict. Here, we quantify the relative impacts of multiple factors on species interactions for a diverse array of intertidal organisms, using our own experiments across a range of environments in New Zealand and North America. Interaction strengths are related to organism body size and trophic level, but are relatively insensitive to environmental conditions associated with tidal height. Although species at higher trophic levels exert stronger per‐capita effects on other taxa, their population‐level impacts are equivalent to basal trophic groups. This indicates that interaction intensity is largely based on requirements for resources, such as food or space, that follow allometric scaling rules. These results demonstrate the potential to predict interactivity based on simple criteria without detailed information on particular species or communities.
Predator control of ecosystem nutrient dynamics
Authors: Schmitz Oswald J. , Hawlena Dror , Trussell Geoffrey C.
Published: June 2010

Predators are predominantly valued for their ability to control prey, as indicators of high levels of biodiversity and as tourism attractions. This view, however, is incomplete because it does not acknowledge that predators may play a significant role in the delivery of critical life‐support services such as ecosystem nutrient cycling. New research is beginning to show that predator effects on nutrient cycling are ubiquitous. These effects emerge from direct nutrient excretion, egestion or translocation within and across ecosystem boundaries after prey consumption, and from indirect effects mediated by predator interactions with prey. Depending on their behavioural ecology, predators can create heterogeneous or homogeneous nutrient distributions across natural landscapes. Because predator species are disproportionately vulnerable to elimination from ecosystems, we stand to lose much more from their disappearance than their simple charismatic attractiveness.
Predictors of morbidity in patients with indwelling ureteric stents: results of a prospective study using the validated Ureteric Stent Symptoms Questionnaire
Authors: Giannarini Gianluca , Keeley Jr Francis X. , Valent Francesca , Manassero Francesca , Mogorovich Andrea , Autorino Riccardo , Selli Cesare
Published: June 2010

Study Type – Therapy (case series) Level of Evidence 4

What’s known on the subject? and What does the study add?

Although it has long been known that ureteric stenting is associated with significant morbidity in a high proportion of patients, predictors of morbidity remain largely elusive.

In a multivariable analysis of potential predictors of morbidity using the Ureteric Stent Symptoms Questionnaire, an easy‐to‐determine variable, i.e. the location of stent distal loop with respect to body midline, emerged as the strongest predictor of morbidity. Patients with stent distal loop crossing the midline experienced worse symptoms. The visualization of stent distal loop may, thus, help identify patients at higher risk of morbidity requiring early management.

OBJECTIVE To assess the predictors of morbidity in patients with indwelling ureteric stents using a validated questionnaire.

PATIENTS AND METHODS Eighty‐six consecutive patients with indwelling double‐J ureteric stent of different length and size enrolled at an Italian tertiary academic centre were prospectively evaluated with the Italian‐validated Ureteric Stent Symptoms Questionnaire (USSQ), which explores the stent‐related symptoms in six domains. Ureteric stents were placed for benign ureteric obstruction or after uncomplicated ureterorenoscopy, and were all removed after 28 days. The questionnaire was administered on days 7 and 28 after stent placement and on day 28 after removal. A plain abdominal X‐ray was performed on days 7 and 28 after placement to determine stent location. Univariable and multivariable analyses tested the association of patient age, sex and body mass index (BMI), and stent side, length, calibre and distal loop location, with the index score of the various domains on days 7 and 28.

RESULTS All patients completed the study. At multivariable analysis, on day 7, sex, BMI and stent calibre were significantly associated with one domain (general health, body pain and work performance, respectively), while location of stent distal loop was significantly associated with five domains (urinary symptoms, body pain, general health, work performanc, and sexual matters). On day 28, body mass index was significantly associated with two domains (body pain and general health), while location of stent distal loop remained significantly associated with the same five domains (urinary symptoms, body pain, general health, work performance and sexual matters).

CONCLUSION Location of stent distal loop with respect to midline had the strongest association with most domains of the USSQ on both days 7 and 28 after stent placement. The visualization of stent distal loop crossing the midline may therefore identify patients at higher risk of post‐procedural morbidity requiring early management.
Effects of pravastatin and rosuvastatin on the generation of adiponectin in the visceral adipose tissue in patients with coronary artery disease
Authors: Yokoyama Hiroaki , Saito Shin , Daitoku Kazuyuki , Fukuda Ikuo , Higuma Takumi , Hanada Hiroyuki , Osanai Tomohiro , Okumura Ken
Published: June 2010

Pravastatin increases the plasma adiponectin level. We examined whether this is a statins’ class effect or specific to pravastatin. Of 50 patients undergoing cardiac surgery for coronary artery disease (CAD, n = 36) and valvular heart disease (VHD, n = 14), 23 with CAD and serum LDL‐cholesterol level >100 mg/dL were randomized to pravastatin at 10 mg/day (PRAVA, n = 12) or rosuvastatin at 2.5 mg/day (ROSUVA, n = 11) for 2 months, and the other 13 with CAD and LDL‐cholesterol ≤100 mg/dL were not treated with statin (Non‐statin, n = 13). Patients with VHD did not have CAD and were not treated with statin. Blood was sampled at baseline and surgery. Visceral (VIS) and subcutaneous (SC) adipose tissues were harvested during surgery. At baseline, the plasma adiponectin level was low in patients with CAD compared with that of patients with VHD. At surgery, adiponectin level in PRAVA was increased to the level in VHD, whereas those in ROSUVA and Non‐statin were unchanged. VIS contents and gene expressions of adiponectin in PRAVA and VHD were similar to each other and were both higher than those in Non‐statin and ROSUVA. SC content and gene expression of adiponectin were similar among 4 groups. Protein carbonyl (PC) level, an indicator of oxidative stress, in VIS was lower in PRAVA and VHD than in ROSUVA and Non‐statin. There was a negative correlation between the plasma adiponectin and VIS PC levels (r = −0.41, P < 0.05). Thus, pravastatin increases adiponectin generation, whereas rosuvastatin does not.
Achieving low defibrillation thresholds at implant: pharmacological influences, RV coil polarity and position, SVC coil usage and positioning, pulse width settings, and the azygous vein
Authors: Kroll Mark W. , Schwab Joerg O.
Published: June 2010

Approximately 30% of implantable cardioverter defibrillator (ICD) patients still die of sudden death. A major cause of these sudden deaths is the failure to defibrillate because of failure to achieve a low defibrillation threshold (DFT). Anti‐arrhythmic drugs can have a profound positive or negative effect on the DFT. Unfortunately, present clinical practice continues to feature many procedures and tactics that have minimal to negative DFT benefit. In addition, many demonstrated helpful tactics are not understood or followed. This review covers the optimal RV (right ventricular) coil position and polarity, superior vena cava (SVC) coil positioning and usage, pulse width settings, and azygous vein coil implants. Specifically, the RV coil should be set to an anodal polarity and never ‘reversed’. The optimal RV coil position appears to be along the mid‐septum. The SVC coil should be kept out of the right atrium and placed in the innominate vein junction. The SVC coil should be always on for high impedance patients. For low impedance patients, the SVC coil should be set on or off depending on which setting gives the lowest DFT. Pulse widths should be set to correspond to optimally charging and discharging a cardiac membrane time constant of between 3.5 and 4.5 ms. For the highest DFT patients, a separate coil should be placed in the azygous vein and connected to the ICD ‘SVC’ port. Anachronistic approaches such as the use of polarity reversal, apical RV coil tip forcing, and subcutaneous arrays are also discussed.
Antidepressant‐like effect of carvacrol (5‐Isopropyl‐2‐methylphenol) in mice: involvement of dopaminergic system
Authors: Melo Francisca Helvira Cavalcante , Moura Brinell Arcanjo , de Sousa Damião Pergentino , de Vasconcelos Silvânia Maria Mendes , Macedo Danielle Silveira , Fonteles Marta Maria de França , Viana Glauce Socorro de Barros , de Sousa Francisca Cléa Florenço
Published: June 2010

Carvacrol (5‐isopropyl‐2‐methylphenol) is a monoterpenic phenol present in the essential oil of many plants. It is the major component of the essential oil fraction of oregano and thyme. In this study, the effect of carvacrol was investigated in two behavioral models, the forced swimming and tail suspension tests in mice, to investigate the possible antidepressant effect of this substance. Additionally, the mechanisms involved in the antidepressant‐like effect of carvacrol in mice were also assessed. Carvacrol (cvc) was administered orally at single doses of 12.5, 25 and 50 mg/kg. The acute treatment of cvc decreased the immobility time in the forced swimming and tail suspension tests without accompanying changes in ambulation in the open‐field test. The anti‐immobility effect of carvacrol (25 mg/kg) was not prevented by pretreatment of mice with p‐chlorophenylalanine, prazosin and yohimbine. On the other hand, the pretreatment of mice with SCH23390 or sulpiride completely blocked the antidepressant‐like effect of carvacrol (25 mg/kg) in the forced swimming test. These results show that carvacrol presents antidepressant effects in the forced swimming and tail suspension tests; this effect seems to be dependent on its interaction with the dopaminergic system, but not with the serotonergic and noradrenergic systems. Keywords: Carvacrol; Antidepressant; Forced swimming; Tail suspension; Dopaminergic system.
Role of drugs and devices in patients at risk of sudden cardiac death
Authors: Boriani Giuseppe , Diemberger Igor , Valzania Cinzia , Biffi Mauro , Martignani Cristian , Raschi Emanuel , Mantovani Valentina , Ziacchi Matteo , Bertini Matteo , De Ponti Fabrizio , Branzi Angelo
Published: June 2010

The search for effective treatment for preventing sudden cardiac death (SCD) initially started with anti‐arrhythmic agents in high‐risk patients, but the use of randomized controlled trials clearly led to the conclusion that an approach based on anti‐arrhythmic agents is not useful, and sometimes potentially harmful (the risk of arrhythmic death was increased up to 159% in CAST study). Today the approach to SCD prevention includes considering both the setting of patients who have already presented a cardiac arrest or a malignant ventricular tachyarrhythmias (secondary preventions of SCD) and the much broader setting of primary prevention in patients at variable degrees of identifiable risk. For secondary prevention of SCD, implantable cardioverter defibrillation is now the standard of care (the risk of overall mortality may be reduced by 20–31%), and anti‐arrhythmic agents, specifically amiodarone, have only a complementary role (for reducing device activations or for preventing atrial fibrillation). For primary prevention of SCD in high‐risk patients, cardioverter defibrillators have nowadays specific indications in patients with left ventricular dysfunction (often in combination with cardiac resynchronization therapy), where the risk of overall mortality may be reduced by 23–54%. For the large number of subjects who have some risk of SCD, but are not identified as at high risk of SCD, a series of drugs could exert a favorable effect (beta‐blockers, angiotensin‐converting enzyme inhibitors, angiotensin receptor blocker agents, statins, omega‐3 fatty acids and aldosterone antagonists), and for some of them evidence is emerging, from subgroup analysis, of possible SCD prevention capabilities.
On the role of operations research practice in strategic environmental impact assessment
Authors: Clímaco João , Craveirinha José
Published: June 2010

As emphasized in the Resource Manual to Support Application of the Protocol on Strategic Environmental Assessment (SEA) (United Nations Economic Commission for Europe Convention on environmental impact assessment in a Transboundary Context) in complex contexts, the SEA process has great potential in the development and comparison of alternatives. In this work, we discuss some roles and implications of operations research practice in the framework of this type of process. A case study, currently topical in Portugal, will be used to motivate and illustrate the presentation.
Le secteur informel en Inde: effets de la mondialisation et des réformes
Authors: Siggel Eckhard
Published: June 2010

La mondialisation et les réformes économiques ont habituellement une incidence sur le secteur formel, tandis que le secteur informel fonctionne en marge de la réglementation. Cependant, les liens multiples qui existent entre eux affectent ce dernier de diverses manières. La segmentation du marché du travail et les migrations étaient traditionnellement utilisées pour expliquer ces effets: les travailleurs licenciés du secteur formel augmentent l'offre de travail informel, d'où une diminution des salaires et un accroissement de la pauvreté. L'auteur examine si cette hypothèse se vérifie en Inde, suite aux réformes économiques des années quatre‐vingt‐dix, et il trouve un modèle plus adapté, reposant à la fois sur l'augmentation de l'offre et de la demande de travail, sous l'action de l'externalisation, des transferts de compétences et de la création d'entreprises.
Potential oral manifestations of cardiovascular drugs
Authors: Habbab KM , Moles DR , Porter SR
Published: June 2010

Oral Diseases (2010) 16, 769–773

Objective:  The aim of this work was to determine the frequency and nature of oral manifestations secondary to use of cardiovascular drugs.

Methods:  Five hundred and thirty one patients attending an adult cardiology clinic in Saudi Arabia were questioned about the occurrence of oral dryness, dysgeusia, or burning sensation and were clinically evaluated for the presence of oral mucosal or gingival disease. Data were statistically analyzed with chi‐squared tests, odds ratios and Student’s t‐test.

Results:  Oral symptoms and/or signs were recorded in 75 (14.1%) patients with xerostomia being the most common (7.5%), followed by lichenoid (lichen planus‐like) lesions (3.6%) and dysgeusia (1.9%). Xerostomia was significantly more frequent in patients with a history of diabetes mellitus and in female patients (P < 0.05). There were no statistically significant differences (P > 0.05) between patients with or without oral manifestations when age, gender, cardiovascular risk factor, cardiac disease, type of cardiac drug used or the number of medications were assessed. There was a trend for xerostomia to be less frequent in patients receiving therapy with angiotensin converting enzyme inhibitors and a slight trend of xerostomia to be more likely with increased number of non‐cardiac and total number of agents per subject. The number of non‐cardiac and total medications taken by patients with potential oral manifestations tended to be greater than that of patients without oral manifestations.

Conclusions:  The frequency of potential oral manifestations in patients receiving cardiovascular agents was 14.1%. The occurrence and character of the oral manifestations had no significant relation with individual cardiac drugs, although there was a trend for oral manifestations to be likely with increasing number of drugs.
Cryogenic inductively coupled plasma etching for fabrication of tapered through-silicon vias
Authors: Kamto A. , Divan R. , Sumant A. V. , Burkett S. L.
Published: June 2010

Vertical interconnects pose an interesting method for heterogeneous integration of electronic technologies allowing three-dimensional (3D) stacking of microelectromechanical systems devices and integrated circuit components. The vertical interconnects, referred to as through-silicon vias, begin with the formation of blind vias in silicon that are eventually exposed by mechanically lapping and polishing the wafer back side. Inductively coupled plasma (ICP) etching using SF6∕O2 gas chemistry at cryogenic temperatures has been investigated as a way to form vias with a tapered sidewall. The point in creating a controlled taper is so that subsequent thin films can be deposited along the sloped sidewall that line the via with insulation, barrier, and seed films. This tapering is necessary if the via lining processes do not provide adequate conformal coverage, a common problem for conventional low temperature deposition processes. In our process for lining the via sidewall, plasma enhanced chemical vapor deposited silicon dioxide is used to insulate vias from the surrounding silicon. Both Ti and Cu are sputter deposited and provide protection from copper migration and a seed film for Cu electrodeposition, respectively. After etching and lining, the vias are filled by reverse pulse plating of Cu. Vias are 20–25μm in diameter and etched using different masking materials. The effect of changing gas flow rates, chamber pressure, ICP power, and substrate temperature on etch rate, via profile, and sidewall morphology will be presented. These parameters are critical in the optimization of an etch process for vias of specific dimensions to be used in 3D integration.
Charging/discharging dynamics of CdS and CdSe films under photoillumination using dynamic x-ray photoelectron spectroscopy
Authors: Sezen Hikmet , Suzer Sefik
Published: June 2010

Thin films of CdS and CdSe are deposited on HF-cleaned SiO2∕Si substrates containing ∼5nm thermally grown silicon oxide. x-ray photoelectron spectroscopy (XPS) data of these films are collected in a dynamic mode, which is based on recording the spectrum under modulation with an electrical signal in the form of ±10V square-wave pulses. Accordingly, all peaks are twined and shifted with respect to the grounded spectrum. The binding energy difference between the twinned peaks of a dielectric system has a strong dependence on the frequency of the electrical stimuli. Therefore, dynamic XPS provides a means to extract additional properties of dielectric materials, such as effective resistance and capacitance. In this work, the authors report a new advancement to the previous method, where they now probe a photodynamic process. For this reason, photoillumination is introduced as an additional form of stimulus and used to investigate the combined optical and electrical response of the photoconductive thin films of CdS and CdSe using dynamic XPS.
Effect of polyhedral oligomeric silsesquioxane concentration on the friction and wear of dental polymers
Authors: Bhushan Bharat , Palacio Manuel , Schricker Scott
Published: June 2010

Organic-inorganic hybrid materials, such as polyhedral oligomeric silsesquioxanes (POSS), have the potential to improve the mechanical properties of methacrylate based composites and resins used in dentistry. In this article, the authors investigated the effect of the concentration of trismethacryl isobutyl POSS on the in vitro friction and wear of a composite resin mainly composed of ethoxylated bisphenol A dimethacrylate and triethyleneglycol dimethacrylate and filled with silanated silica glass. Experiments on both de-ionized water and saliva substitute were conducted. The effect of POSS on the friction and wear of the unfilled polymer resin immersed in saliva substitute were also investigated. From pin-on-disk experiments, it was found that the addition of small amounts (0.5–3 wt %) of POSS improves the friction and wear resistance of both the resin composite and the polymer resin. Samples with a higher POSS concentration (5%) showed an opposite effect, which illustrates the limited range where the reinforcement properties of POSS can operate. This concentration dependence is attributed to phase separation at higher concentrations of POSS, which affects the structural integrity, and hence, the friction and wear properties of the resin composite and the polymer resin. Depth dependence of the coefficient of friction was observed in the composite, indicating inhomogeneity from curing. The results presented in this article can serve as a useful guide in the development of novel reinforced resin composites and polymer resins for dental applications.
Thickness monitoring of graphene on SiC using low-energy electron diffraction
Authors: Fisher P. J. , Luxmi  , Srivastava N. , Nie S. , Feenstra R. M.
Published: June 2010

The formation of epitaxial graphene on SiC is monitored in situ using low-energy electron diffraction (LEED). The possibility of using LEED as an in situ thickness monitor of the graphene is examined. The ratio of primary diffraction spot intensities for graphene compared to SiC is measured for a series of samples of known graphene thickness (determined using low-energy electron microscopy). It is found that this ratio is effective for determining graphene thicknesses in the range of 1–3 ML. Effects of a distribution of graphene thicknesses on this method of thickness determination are considered.
Morphology of TiN thin films grown on MgO(001) by reactive dc magnetron sputtering
Authors: Ingason A. S. , Magnus F. , Olafsson S. , Gudmundsson J. T.
Published: June 2010

Thin TiN films were grown by reactive dc magnetron sputtering on single-crystalline MgO(001) substrates at a range of temperatures from room temperature to 600 °C. Structural characterization was carried out using x-ray diffraction and reflection methods. TiN films grow epitaxially on the MgO substrates at growth temperatures of 200 °C and above. The crystal coherence length determined from Laue oscillations and the Scherrer method agrees with x-ray reflection thickness measurements to 6% and within 3% for growth temperatures of 200 and 600 °C, respectively. For lower growth temperatures the films are polycrystalline but highly textured and porous.
Fabrication and characterization of ink jet processed organic thin film transistors with poly-4-vinylphenol gate dielectric
Authors: Eum Kyuhag , Kim Kyohyeok , Han Jaejun , Chung Ilsub
Published: June 2010

Organic thin film transistors (OTFTs) were fabricated on polyethersulphone substrate using 6,13-bis(triisopropylsilylethynyl) (TIPS) pentacene as an active layer and cross-linked poly-4-vinylphenol (PVP) as a gate dielectric. Prior to adoption of PVP as a gate dielectric, the PVP print condition was optimized using a metal-insulator-metal structure and making a comparison with spin coated devices in terms of the leakage current, breakdown voltage, and dielectric constant. Then, OTFTs were fabricated with an optimized PVP gate dielectric and a TIPS pentacene active layer using an ink jet printer. The electrical properties such as the field effect mobility, Ion/Ioff ratio, and threshold voltage had values of 0.055 cm2/V s, 103, and −2.6 V, respectively. The smaller Ion/Ioff ratio can be attributed to the smaller coverage of the TIPS pentacene layer due to the plateletlike crystalline structures.
Ultrashort pulse laser ablation for depth profiling of bacterial biofilms
Authors: Milasinovic Slobodan , Liu Yaoming , Gasper Gerald L. , Zhao Youbo , Johnston Joanna L. , Gordon Robert J. , Hanley Luke
Published: June 2010

Sample ablation by pulsed lasers is one option for removing material from a sample surface for in situ depth profiling during imaging mass spectrometry, but ablation is often limited by laser-induced damage of the remaining material. A preliminary evaluation was performed of sub-100-fs, 800 nm pulsed laser ablation for depth profiling of bacterial biofilms grown on glass by the drip flow method. Electron and optical microscopy were combined with laser desorption vacuum ultraviolet postionization mass spectrometry to analyze biofilms before and after ablation. Ultrashort laser pulses can ablate 10–100 μm thick sections of bacterial biofilms, leaving behind a layer of lysed cells. However, mass spectra from intact and ablated biofilms doped with antibiotic are almost identical, indicating little chemical degradation by ablation. These results are consistent with prior observations from laser surgery and support the use of ultrashort pulse laser ablation for minimally disruptive depth profiling of bacterial biofilms and intact biological samples.
Hot-electron transport studies of the Ag/Si(001) interface using ballistic electron emission microscopy
Authors: Garramone J. J. , Abel J. R. , Sitnitsky I. L. , LaBella V. P.
Published: June 2010

Ballistic electron emission microscopy has been utilized to investigate the hot-electron transport properties of the Ag/Si(001) Schottky diode utilizing metal films deposited both in situ and ex situ. The Schottky barrier heights are measured to be 0.57±0.02 and 0.59±0.02 eV for the ex situ and in situ depositions, respectively. The metal overlayers demonstrate typical Volmer–Weber growth when deposited on the Si(001) semiconducting substrate, as seen in the scanning tunneling microscopy images. An enhancement in hot-electron transmission is measured for the in situ deposited metal films when compared to the ex situ films.
Deposition of aluminum-doped zinc oxide thin films for optical applications using rf and dc magnetron sputter deposition
Authors: Sivakumar Kousik , Rossnagel S. M.
Published: June 2010

Aluminum-doped zinc oxide films were deposited by dc and rf magnetron sputtering from ZnO(98%)Al2O3(2%) target at room temperature on silicon and glass substrates under a variety of process conditions with the goal of attaining the highest transmittance and lowest resistivity for photovoltaic applications. The magnetron power and pressure were varied. For many dielectric deposition systems, added oxygen is necessary to achieve the appropriate stoichiometry. The effect of oxygen on film properties was then studied by varying the oxygen partial pressure from 1.5×10−5 to 4.0×10−5 T at a constant Ar pressure, with the result that any added oxygen was deleterious. Films deposited under power, pressure, and low-oxygen conditions were then characterized for electrical and optical properties. Following this, the dc and rf sputtered films were annealed at up to 400 °C seconds using rapid thermal annealing (RTA), and the influence of annealing on resistivity, transmittance, band gap, as well as grain growth and stress was studied. The effect of RTA was immediate and quite significant on dc films while the effect on rf films was not as profound. As-deposited rf films had a higher average transmittance (87%) and lower resistivity (5.5×10−4 Ω cm) compared to as-deposited dc films (84.2% and 8.9×10−4 Ω cm). On the other hand, after RTA at 400 °C for 60 s, dc films exhibited better average transmittance (92.3%) and resistivity (2.9×10−4 Ω cm) than rf films (90.7% and 4.0×10−4 Ω cm). The band gap of dc films increased from 3.55 to 3.80 eV while that of rf films increased from 3.76 to 3.85 eV. Finally, dc and rf films were textured in 0.1% HCl and compared to U-type Asahi glass for resistivity and transmittance.
Frequency of germline hereditary non-polyposis colorectal cancer gene mutations in patients with multiple or early onset colorectal adenomas
Authors: Beck N E , Tomlinson I P M , Homfray T F R , Frayling I M , Hodgson S V , Bodmer W F
Published: June 2010

Background—The hereditary non-polyposis colorectal cancer (HNPCC) syndrome is caused by germline mutations in mismatch repair genes and predisposes individuals to cancers of the colon and other specific sites. On theoretical grounds, it is expected that patients with HNPCC also develop more colorectal adenomas than the general population. In essence, if the mutation rate is raised owing to mutations at a mismatch repair locus, more mutations are expected at loci such as APC (adenomatous polyposis coli) and more adenomas will start to grow. Not all data support this expectation, however.

Aim—To search for germline mutations at HNPCC loci in patients with multiple adenomas.

Subjects—Twenty five patients (without known APC mutations) who have developed colorectal adenomas in unusually large numbers and, in some cases, at an early age.

Methods—Germline APC mutations were excluded using the protein truction test for exon 15 and mismatch chemical cleavage analysis for remaining exons. Germline HNPCC mutations were detected by using PCR and single strand conformation polymorphism analysis.

Results—Just one germline HNPCC mutation was found (4% of cases) and this was of uncertain functional effect.

Conclusions—In general, germline HNPCC mutations are not responsible for the phenotype of patients with multiple colonic adenomas. It is possible that patients with HNPCC tend to develop adenomas more frequently and earlier than the general population, but that this effect is relatively subtle. These results suggest that individuals with colorectal adenomas only should not strictly be classified as “affected” in HNPCC families (although they should certainly not be classified as “unaffected” either and may warrant intensive screening). In the absence of a personal or strong family history of colorectal cancer, it is probably not worthwhile performing diagnostic or predictive genetic testing for HNPCC mutations in subjects with colorectal adenomas. Although undetected APC mutations may be responsible for some of the phenotypes in this sample, as yet uncharacterised adenoma predisposing genes probably exist.
Atropine inhibits gastric distension and pharyngeal receptor mediated lower oesophageal sphincter relaxation
Authors: Mittal R K , Chiareli C , Liu J , Holloway R H , Dixon W
Published: June 2010

Background—Atropine decreases the frequency of transient lower oesophageal sphincter relaxation (TLOSR) through an unknown mechanism. Gastric distension and pharyngeal receptor excitation are two possible sources for the afferent stimulus responsible for TLOSR.

Aims—To determine whether atropine affects gastric distension induced TLOSR and pharyngeal receptor mediated lower oesophageal sphincter (LOS) relaxation.

Methods—Oesophageal manometry and pH recordings were performed in 10 healthy volunteers on two separate days in the postprandial setting, following either atropine (15 μg/kg intravenous bolus and 4 μg/kg/h as a maintenance dose) or placebo. Pharyngeal receptor mediated LOS relaxation was studied in nine subjects by rapid injection of minute amounts of water (0.05, 0.1, 0.2, 0.3, and 0.4 ml) in the pharynx before and after atropine. Gastric distension mediated TLOSR was studied in eight subjects by insufflating the stomach with 300, 600 and 900 ml of CO2 before and after atropine.

Results—Atropine reduced the frequency of spontaneous gastro-oesophageal reflux and TLOSR compared with placebo (p<0.05). Pharyngeal stimulation resulted in bolus volume dependent LOS relaxation. Atropine decreased the frequency and amplitude of pharyngeal receptor mediated LOS relaxation at bolus volumes of 0.05, 0.1, and 0.2 ml. Gastric distension resulted in intermittent episodes of TLOSR. The frequency of gastric distension induced TLOSR was significantly decreased by atropine.

Conclusion—(1) Atropine reduces the frequency of spontaneous reflux and TLOSR in normal subjects; and (2) gastric distension induced TLOSR and pharyngeal receptor mediated LOS relaxation is inhibited by atropine.
Sleep and gastric function in irritable bowel syndrome: derailing the brain-gut axis
Authors: Orr W C , Crowell M D , Lin B , Harnish M J , Chen J D Z
Published: June 2010

Background—Recently, several studies have shown an alteration in bowel function during sleep in patients with irritable bowel syndrome (IBS), and a recent study also suggests a remarkable increase in rapid eye movement (REM) sleep. These studies have suggested that an alteration in CNS function may play an important role in the pathogenesis of IBS.

Aims—To confirm the presence of an alteration in REM sleep in patients with IBS and to assess the relation between sleep and a non-invasive measure of gastric functioning, the electrogastrogram (EGG).

Patients—Ten patients with IBSand 10 age and sex matched normal volunteers.

Methods—All subjects slept one night in the sleep laboratory and underwent polysomnographic monitoring to determine sleep patterns, and recording of the EGG from surface electrodes.

Results—The IBS group had a notable and significant increase in the percentage and duration of REM sleep (p<0.05). The control group had a decrease in the amplitude of the dominant EGG frequency from waking to non-REM sleep (p<0.05), and a subsequent increase in the amplitude from non-REM to REM sleep (p<0.05). No such changes were noted in the patients with IBS.

Conclusions—Results confirmed the enhancement of REM sleep in patients with IBS and suggested an intrinsic alteration in autonomic and CNS functioning in patients with IBS.
Acute hyperglycaemia affects anorectal motor and sensory function in normal subjects
Authors: Russo A , Sun W M , Sattawatthamrong Y , Fraser R , Horowitz M , Andrews J M , Read N W
Published: June 2010

Background—The pathogenesis of anorectal dysfunction, which occurs frequently in patients with diabetes mellitus, is poorly defined. Recent studies indicate that changes in the blood glucose concentration have a major reversible effect on gastrointestinal motor function.

Aims—To determine the effects of physiological changes in blood glucose and hyperglycaemia on anorectal motor and sensory function in normal subjects.

Subjects—In eight normal subjects measurements of anorectal motility and sensation were performed on separate days while blood glucose concentrations were stabilised at 4, 8, and 12 mmol/l.

Methods—Anorectal motor and sensory function was measured using a sleeve/sidehole catheter incorporating a balloon, and electromyography.

Results—The number of spontaneous anal relaxations was greater at 12 mmol/l than at 8 and 4 mmol/l glucose (p<0.05 for both). Anal squeeze pressures were less at a blood glucose of 12 mmol/l when compared with 8 and 4 mmol/l (p<0.05 for both). During rectal distension, residual anal pressures were not significantly different between the three blood glucose concentrations. Rectal compliance was greater (p<0.05) at a blood glucose of 12 mmol/l when compared with 4 mmol/l. The threshold volume for initial perception of rectal distension was less at 12 mmol/l when compared with 4 mmol/l (40 (20–100) ml versus 10 (10–150) ml, p<0.05).

Conclusions—An acute elevation of blood glucose to 12 mmol/l inhibits internal and external anal sphincter function and increases rectal sensitivity in normal subjects. In contrast, physiological changes in blood glucose do not have a significant effect on anorectal motor and sensory function.