bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors influencing the outcome of non‐surgical periodontal treatment: a multilevel approach
Authors: Tomasi Cristiano , Leyland Alastair H. , Wennström Jan L.
Published: July 2007

Aim: To investigate, by means of multilevel analysis, factors that may affect the short‐term clinical outcome of non‐surgical periodontal treatment.

Materials and Methods: Forty‐one patients randomly assigned to two protocols of non‐surgical therapy were included. The impact of different covariates on the probability of “pocket closure” [i.e. probing pocket depth (PPD)4 mm] was explored using a logistic multilevel model. The impact on the final PPD was explored using a continuous multilevel model.

Results: The logistic model revealed a significant impact of smoking (p<0.001), presence of plaque at the site (p<0.001) and location of the pocket at a multi‐rooted tooth (p<0.001). The model explained 44% of the total variability. Of the unexplained variance, 19% was attributed to inter‐patient variability. The continuous model revealed the same factors to be significant and an additional significant impact of interactions between the covariates. The R2 was 0.50 and the random slopes model revealed an increase in the variability of the final pocket depth with an increase in the initial PPD.

Conclusion: Smoking habits, plaque at site level and tooth type were significant factors in determining the short‐term clinical outcome of non‐surgical periodontal treatment.
Relations between the bone density values from computerized tomography, and implant stability parameters: a clinical study of 230 regular platform implants
Authors: Turkyilmaz Ilser , Tumer Celal , Ozbek Esma Nida , Tözüm Tolga F.
Published: July 2007

Aims: The objective of this study was to determine the relationship between bone density, insertion torque, and implant stability at implant placement.

Materials and Methods: One‐hundred and eight patients were treated with 230 Brånemark System implants. A computerized tomography (CT) machine was used for pre‐operative evaluation of the jaw bone for each patient. The maximum insertion torque values were recorded with the OsseoCare equipment. Implant stability measurements were performed with the Osstell machine for only 142 implants.

Results: The mean bone density and insertion torque values were 721±254 Hounsfield unit (HU) and 39.1±7 N cm for 230 implants, and the correlation was significant (r=0.664, p<0.001). The mean bone density, insertion torque, and resonance frequency analysis values were 751±257 HU, 39.4±7 Nc m, and 70.5±7 implant stability quotient (ISQ), respectively, for 142 implants. Statistically significant correlations were found between bone density and insertion torque values (p<0.001); bone density and ISQ values (p<0.001); and insertion torque and ISQ values (p<0.001).

Conclusion: The bone density values from pre‐operative CT examination may provide an objective assessment of bone quality, and significant correlations between bone density and implant stability parameters may help clinicians to predict primary stability before implant insertion.
Replantation after extended dry storage of avulsed permanent incisors: report of a case
Authors: Cobankara Funda Kont , Ungor Mete
Published: July 2007

Abstract –  A 15‐year‐old boy lost his maxillary right and left central incisor teeth in a bicycle accident. He was referred to our clinic 1 week after the injury. The crown‐root integrities of both the teeth were not damaged. Although the teeth were stored under dry conditions for 1 week, reimplantation of the teeth was planned to retain the teeth in the mouth for as long a period as possible because of the patient's age. Following the debridement and sterilization of root surfaces in 2.5% NaOCl, root canals were prepared and filled with calcium hydroxide. Then, about 2 mm of the apexes were resected to ensure that the roots easily seated in the alveolar socket and the prepared cavities in root ends were obturated with the amalgam. The teeth were placed into their respective sockets and splinted temporarily. The root canal therapy was completed 5 weeks later. Ankylosis was observed radiographically after 10 months. The patient is now 23 years old and he is still able to use both the central incisors functionally. However, there is a pink appearance on the cervical buccal surface of left central incisor because of progressive replacement resorption. In this case, the new treatment plan is to perform a permanent restoration with dental implants following the extraction of both teeth. Even though the long‐term prognosis is uncertain, this treatment technique has provided an advantage for the patient in his adolescent period by maintaining the height of alveolar bone and making the provision of an aesthetically acceptable permanent restoration at a later age possible.
Prevalence and risk factors related to traumatic dental injuries in Brazilian schoolchildren
Authors: Soriano Evelyne Pessoa , Caldas Arnaldo de França , Carvalho Marcus Vitor Diniz De , Amorim Filho Hugo De Andrade
Published: July 2007

Abstract –  The aim of this study was to investigate the risk factors associated with the occurrence of dental trauma in permanent anterior teeth of schoolchildren in Recife, Brazil. It included a random sample of 1046 boys and girls aged 12 attending both public and private schools. The sample size was calculated using a 95% confidence interval level; a statistical significance of 5% (α); a sample power of 80%; and an odds ratio of 1.55. The sample selection was carried out in two stages: first, schools were selected by simple sampling, and then children were chosen using a proportionality coefficient. Data were collected through clinical examinations and interviews, after examiner calibration. Dental trauma was classified according to Andreasen criteria. Overjet was considered a risk factor when it presented values higher than 5 mm. Lip coverage was classified as adequate or inadequate, while obesity was considered according to National Center for Health Statistics procedures for the assessment of nutritional status. Data were summarized and analyzed using the statistical software SPSS. The prevalence of dental injuries was 10.5%. Boys experienced more injuries than girls, 12.2% and 8.8%, respectively (P > 0.05). Children attending public schools presented more traumatic injuries than those from private schools, 11.4% and 9.5%, respectively, but there was no statistically significant difference (P > 0.05). There was a statistically significant difference between traumatic dental injuries and overjet (P < 0.05); between traumatic dental injuries and inadequate lip coverage (P = 0.000), and between obesity and dental trauma (P < 0.05). It was concluded that boys attending public schools and presenting an overjet size >5 mm, inadequate lip coverage, and obesity were more likely to have traumatic dental injuries in Recife, Brazil.
Dentoalveolar trauma in Glasgow: an audit of mechanism and injury
Authors: Wright Graeme , Bell Aileen , McGlashan Gregor , Vincent Carolyn , Welbury Richard R.
Published: July 2007

Abstract –  Traumatic dental injuries in children often require multiple follow‐up visits to the dentist and may have long‐term consequences for the developing dentition. The aim of this audit was to examine age, gender, location, time of year, mechanism of injury and type of injury sustained in relation to dentoalveolar trauma in children attending the paediatric dental trauma clinic at Glasgow Dental Hospital from 2002 to 2004, and to compare our findings with data in the published literature. Males suffered 60% of all dental trauma, 79% of sporting injuries and 85% of assaults. The injuries in males were more severe, representing 65% of enamel dentine and pulp fractures, 100% of crown root fractures and 66% of crown root and pulp fractures. A peak for trauma was seen in the 8–11‐year‐old group (43%). The majority of injuries in the under four age group resulted from falls (87%). Taken as a whole, falls accounted for 49%, sports related injuries 18%, bicycle and scooter 13%, assault 7%, and road traffic accidents 1.5% of all injuries. They also accounted for a far higher percentage of intrusive luxations (67%). The largest proportion of injuries occurred during the summer months (33%). Sixty‐four percent of children suffered trauma to more than one tooth. Fifty‐eight percent of injuries involved the dental hard tissues and pulp and the majority of these (82%) were crown fractures. Most subjects (82%) suffered trauma to their periodontal tissues, (26% concussion or subluxation, 26% lateral luxation and 23% avulsion). Injuries to the supporting bone were uncommon. Sixty‐six percent of all injuries occurred outdoors. Our findings were similar to a number of published studies, but in contrast to several others. More consistency is required in the collection and reporting of trauma data to be able to draw meaningful conclusions by comparison.
Foam sclerotherapy — A possible option in therapy of varicose veins
Authors: Kendler Michael , Wetzig Tino , Simon Jan C.
Published: July 2007

The therapy of varicose veins is multimodal and depends on the individual clinical findings. In addition to compression therapy, invasive approaches for elimination of reflux for the treatment of varicose veins are available, such as surgical and interventional methods and sclerotherapy. The administration of a scle‐rosing agent into a varicose vein results in an occlusion of the treated vein. Recently the use of foam sclerotherapy had a renaissance. Several studies have documented the efficacy of foam sclerotherapy in selected patients. The possibility of treating patients in an outpatient setting, with low costs and rapidly, makes foam sclerotherapy very attractive compared to invasive and minimally invasive methods. However long‐term follow‐ups in properly controlled randomized trials are needed before foam sclerotherapy can be recommended as a routine procedure. This paper introduces the method and the treatment possibilities with foam sclerotherapy in chronic venous insufficiency.
Cutaneous lymphomas in Germany: an analysis of the Central Cutaneous Lymphoma Registry of the German Society of Dermatology (DDG)
Authors: Assaf Chalid , Gellrich Sylke , Steinhoff Matthias , Nashan Dorothée , Weiße Franca , Dippel Edgar , Coors Esther , Stein Anette , Gollin Philippa , Henke Ulrike , Adam‐Murati Sabrina , Koch André , Klemke Claus‐Detlev , Stadler Rudolf , Sterry Wolfram
Published: July 2007

Background: Primary cutaneous lymphomas form a heterogenous group of lymphatic neoplasias.They manifest themselves on the skin and are the second most frequent group of non‐Hodgkin lymphoma (NHL) following gastrointestinal lymphomas.The number of epidemiologic studies is small due to limited availability and limited comparability on population‐based data.

Patients and methods: In the present study the first evaluation of the German Central Registry for Cutaneous Lymphomas (ZRKL) of the German Society of Dermatology (DDG) is undertaken on the basis of 998 patients.The epidemiology of cutaneous lymphomas in Germany is compared to other national or regional lymphoma registries.

Results: Based on the registration of 998 patients from 26 clinics in Germany,a clear predominance of cutaneous T‐cell lymphomas (85 %) in comparison to cutaneous B‐cell lymphomas (14 %) is seen.The most frequent representative of CTCL is mycosis fungoides,composing 62 % of cases with a slight predominance of men (M:F = 1.6:1).Differences are also seen in stage of the disease at first presentation of patients with cutaneous lymphomas.While, for example, 80 % of patients with mycosis fungoides in Germany present in early stages (I–IIA),in the USA 34 % of patients are in the tumor stage or have organ involvement at presentation.

Conclusions: The ZRKL of the DDG for the first time presents epidemiologic data from Germany, allowing comparison with other nations for the study of etio‐logical factors and socioeconomic influences. Further, the ZRKL supports the development of uniform and quality‐oriented diagnostic criteria and therapeutic options. Finally, the ZRKL provides a foundation for future intensive study of clinical and scientific questions regarding cutaneous T‐ and B‐cell lym‐phomas.
Relationship between symptoms of temporomandibular disorders and dental status, general health and psychosomatic factors in two cohorts of 70‐year‐old subjects
Authors: Österberg Tor , Carlsson Gunnar E.
Published: July 2007

Objective:  To study the prevalence of symptoms of temporomandibular disorders (TMD) in two cohorts of 70‐year‐old subjects examined 8 years apart and analyse the relationship between such symptoms and dental status, general health and various background factors.

Materials and methods:  Two cohorts of 70‐year‐old subjects, born in 1922 (n = 422) and 1930 (n = 491) respectively, were examined with an interval of 8 years. A TMD symptom index (0–5) was established on answers to five questions related to TMD symptoms.

Results:  There were no statistically significant differences between the two cohorts for prevalence of TMD symptoms and TMD index, neither for headache, neck ache, bruxism and chewing ability. TMJ sounds was the most prevalent symptom, 14%, whereas other TMD symptoms had low prevalence. The distribution of the TMD symptom index showed that 81% reported no symptoms, 15% one symptom, 3% two symptoms and 1% three to five symptoms. Single TMD symptoms and the TMD index exhibited significant associations (p < 0.001) with bruxism, headache, neck pain and several general health and psychosomatic factors, but with dental status only in women. Logistic regression showed that bruxism, neck pain, mouth dryness and a number of psychosomatic factors were associated with the TMD index.

Conclusions:  Besides TMJ sounds (14%), other TMD symptoms were rarely reported by the 70‐year‐old subjects. The TMD index was significantly associated with bruxism and several general health and psychosomatic complaints but with dental status only in women.
Surgical correction of ventricular septal defect with aortic regurgitation in a dog
Authors: SHIMIZU M. , TANAKA R. , HOSHI K. , HIRAO H. , KOBAYASHI M. , SHIMAMURA S. , YAMANE Y.
Published: July 2007

An 8‐month‐old entire Miniature Dachshund, weighing 4.2 kg, was presented for examination following development of a cough. Ventricular septal defect had been diagnosed tentatively in its infancy on the basis of a cardiac murmur detected by auscultation and echocardiography.

Echocardiography using a B mode right parasternal long‐axis view showed a defect at the atrioventricular junction and a thickened cusp of the aortic valve prolapsing into the defect. Colour‐flow Doppler showed shunt blood flow across the defect at the level of the atrioventricular junction, from left to right. The sinus of Valsalva was dilated, with turbulent blood flow. Aortic regurgitation was also observed. Cardiac catheterisation studies confirmed the diagnosis of a supracristal ventricular septal defect with aortic regurgitation.

Despite medication with digoxin, enalapril and aminophylin, started from the first admission, left ventricular internal dimensions gradually increased, and fractional shortening of the left ventricle gradually decreased. Surgery, with the aid of extracorporeal circulation, to close the ventricular septal defect, was performed 1 year after the initial examination. The aortic valve was left untreated.

Postoperatively, the systolic murmur disappeared. Shunt flow from the left to the right ventricle was no longer observed on echocardiography, however there was still a small amount of aortic regurgitation during diastole visualised with colour‐flow Doppler echocardiography. The prolapse of the cusp of the aortic valve on B‐mode echocardiography was no longer observed and thickening of the cusp had not progressed. Left ventricular function measurement using M mode echocardiography showed a reduced left ventricular volume overload with reduced left ventricular internal dimensions and increased fractional shortening. The cough was relieved and no follow‐up medication was scheduled. Early surgical closure of the ventricular septal defect improved the patient's condition and controlled prolapse and thickening of the aortic valve.
Inheritance of proportionate dwarfism in Angus cattle
Authors: LATTER MR , LATTER BDH , WILKINS JF , WINDSOR PA
Published: July 2007

Objective To determine the mode of inheritance of congenital proportionate dwarfism in Angus and Angus crossbred cattle, initially detected in two commercial beef herds in northern New South Wales.

Design Matings of normal carrier sires to unrelated cows of diverse breeds, and of one carrier sire to his unaffected daughters. An unrelated Piedmontese bull was also mated to unaffected daughters of the carrier sires.

Procedure Two carrier Angus bulls and nine unaffected daughters, all of whom were completely indistinguishable from normal animals, were purchased for controlled breeding studies under known nutritional and disease conditions. Affected and carrier individuals were examined for the presence of obvious chromosomal abnormalities.

Results Angus dwarfism has been successfully reproduced under controlled experimental conditions over successive years using unrelated dams and is undoubtedly heritable. The high frequency of occurrence of affected individuals (23/61 = 0.38 ± .06) among the progeny of matings of the Angus sires to unrelated females of diverse breeding is not compatible with recessive inheritance, because of the negligible frequency of proportionate dwarfism in the breeds of the dams. Both paternal and maternal transmission of the defect was demonstrated, so that imprinting in the strict sense of a gene that is only expressed when received from the male parent appears not to be involved. Tested individuals showed no evidence of gross chromosomal abnormality. Dominant autosomal inheritance with incomplete penetrance was indicated by the lack of expression of the defective gene in the two Angus sires and in three unaffected daughters who produced dwarf calves from matings to the Piedmontese bull.

Conclusions The mode of inheritance is that of a single autosomal dominant gene with a penetrance coefficient of 0.75 ± 0.12, estimated from the observed incidence of 23/61 affected offspring of the two carrier Angus bulls mated to unrelated dams. Simple genetic models involving either (i) an unstable mutant which changes at high frequency to the expressed dominant dwarfing allele during gametogenesis, or (ii) a dominant allele with penetrance determined by an unlinked modifying locus, are shown to be compatible with the experimental data. Both models indicate that penetrance of the dwarfing gene may possibly be higher in matings involving carrier daughters of the two Angus bulls.
The occurrence of congenital heart defects in an inbred herd of pigs in Australia
Authors: HOLYOAKE PK , STEVENSON J. , MORAN C. , STOKES R. , KIRK EP , SUGO E. , HAWTHORNE WJ
Published: July 2007

Objective To report on the first case of congenital heart defects in pigs in Australia.

Design Retrospective analysis of case records from an inbred herd of “Westran’ pigs at the University of Sydney, between January 2001 and December 2004. Detailed gross and histological examination of 15 hearts from pigs that had died or were euthanased in 2004.

Case Details The necropsy records from a population of 471 pigs that had died (106 pigs) or were euthanased for research purposes (365 pigs) were analysed and the incidence of heart defects recorded, together with basic demographic data. No attempts were made to diagnose the condition in live pigs.

Results Congenital heart defects were diagnosed in 6.4% of pigs but this is likely to be an underestimate of the incidence of the deformity. Eighteen pigs died on the farm as a result of the defect, and 12 pigs were diagnosed with the defect as an incidental finding. The most common abnormality seen at necropsy was a sac‐like dilatation on the right lateral surface of the right atrium. This was associated with secondary deformity and hypoplasia of the adjacent left ventricle, interventricular region and part of the right ventricle. All hearts showed atrial septal defects of varying size.

Conclusion This is the first reported case of congenital heart defects in pigs in Australia, and one of less than five reported cases of atrial septal defects in pigs in the world. The authors conclude that there may be an element of genetic predisposition to the malformation, since it has only been reported in this inbred line of pigs.
Effects of temperature and duration of sample storage on the haematological characteristics of western grey kangaroos (Macropus fuliginosus)
Authors: HULME‐MOIR KL , CLARK P. , SPENCER PBS
Published: July 2007

Objective To investigate the effects of storage duration and temperature on haematological analyses performed on blood from the western grey kangaroo (Macropus fuliginosis).

Method Blood samples from five western grey kangaroos were stored at 4°C, 24°C and 36°C. Each sample was analysed haematologically over a 5‐day period.

Results The blood samples maintained optimal stability at 4°C. At this temperature the haematological values remained essentially unchanged for the duration of the study, while samples stored at 36°C and 24°C showed significant changes in some haematological measures by 12 h and 48 h, respectively. Disturbances in leukocyte morphology were evident, to varying degrees, in all samples.

Conclusions Blood samples from macropodids should be tested within 48 h of collection if stored at a room temperature of about 24°C. Where testing is to be delayed for more than 48 h, samples should be refrigerated as soon as possible. Exposure of samples to heat in excess of 24°C should be avoided at all times.
Optimization of the microcrystalline silicon deposition efficiency
Authors: Strahm B. , Howling A. A. , Sansonnens L. , Hollenstein Ch.
Published: July 2007

Cost reduction constraints for microcrystalline silicon thin film photovoltaic solar cells require high deposition rates and high silane gas utilization efficiencies. If the requirements in deposition rate have sometimes been fulfilled, it is generally not the case for the silane utilization. In this work, a reactor-independent methodology has been developed to determine the optimum plasma parameters in terms of deposition rate, silane utilization, and material microstructure. Using this optimization method, a microcrystalline layer has been deposited over a large area at a rate of 10.9Å∕s, with a silane utilization efficiency above 80%.
Velocity dependence and rest time effect on nanoscale friction of ultrathin films at high sliding velocities
Authors: Tao Zhenhua , Bhushan Bharat
Published: July 2007

Micro∕nanoelectromechanical system devices and components often operate at high sliding velocities, and it requires the investigation of friction at high velocities. In this study, the velocity dependence of friction and the rest time effect on friction of hard diamondlike carbon films, soft perfluorodecyltrichlorosilane, and perfluoropolyether films were investigated up to 2×105μm∕s using an ultrahigh velocity stage and a high velocity stage. The velocity dependence of friction was found to vary with films and involve different mechanisms including adhesion due to solid-solid interaction, adhesion due to formation of meniscus bridges, atomic-scale stick slip, high velocity impact of the contacting asperities∕molecules, phase transformation∕tip jump, and viscoelastic shear. The increase in friction as a function of rest time was caused by continued growth and formation of water menisci bridges for the hydrophilic surfaces and continued deformation of soft films.
Growth and electrochemical properties of Li–Ni–Co–Al oxide films
Authors: Ramana C. V. , Zaghib K. , Julien C. M.
Published: July 2007

Li Ni 0.8 Co 0.15 Al 0.05 O 2 films were grown by pulsed-laser deposition (PLD) in the temperature (Ts) range of 30–500°C and oxygen partial pressure (pO2) maintained in the range of 50–150mTorr. The grown films were characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy (RS), and electrochemical measurements in order to understand their growth behavior, surface morphology, local chemical structure, and electrochemical properties. XRD, RS, and SEM measurements indicate that the growth and microstructure of PLD LiNi0.8Co0.15Al0.05O2 films are highly sensitive to the deposition temperature and reactive atmosphere during laser ablation. The fabrication conditions were optimized to produce device quality LiNi0.8Co0.15Al0.05O2 films for electrochemical applications. The charge-discharge profiles of cells using the PLD grown Li(Ni,Co,Al)O2 films as electrodes demonstrate their applicability in microbatteries. A stable capacity of 98μAh∕cm2μm was obtained in the potential range of 4.2–2.5V for LiNi0.8Co0.15Al0.05O2 films grown at 450°C.
Sheet resistance and crystallinity of Ga- and Al-implanted zinc oxide thin films with postannealing
Authors: Matsuda Tokiyoshi , Furuta Mamoru , Hiramatsu Takahiro , Furuta Hiroshi , Hirao Takashi
Published: July 2007

Ion implantation experiments of Ga and Al into sputter-deposited ZnO films were carried out to control the resistivity to form n+-ZnO layers for device fabrication. The difference would be suitable for fabricating source and drain regions of ZnO thin film transistors. Improvement of ZnO crystallinity after the ion implantation was found by x-ray diffraction spectra and a thin film as shift of lattice parameter, enhancement of peak intensity, and a decrease of full width at half maximum in 2θ. The improvement of Ga-implanted ZnO was better than that of the Al-implanted ZnO throughout the experiment. Difference in sheet resistance for seven orders of magnitude between unimplanted ZnO thin film and Ga-implanted ZnO was observed with postannealing at 300°C. The sheet resistance of the ZnO film was decreased to 3.4×102Ω∕◻ with a postimplantation annealing at 450°C.
Thermally regulated valve for minute flows
Authors: Nguyen Hugo , Bejhed Johan , Köhler Johan , Thornell Greger
Published: July 2007

In this work, a gas valve using a microstructured silicon valve lid and a stainless steel valve seat clamped axially together in an aluminum cylinder is investigated. The difference in coefficient of thermal expansion of these components makes the valve open and close on a temperature change. A simple model accounting for elastic deformation of the system’s components is proposed to facilitate design of the valve. By means of a helium leak detector, a typical increase in flow rate from 1.0×10−8to1.0×10−4sccs gaseous helium under a pressure of up to 10bars was observed upon the increase of temperature from 12 to around 98°C, after a single breaking-in. Plastic deformation of the valve seat as a consequence of an imprint of the microstructured valve lid and contaminating particles was studied. Microscopy confirmed a tolerance for particles of up to a few micrometers in diameter. Larger particles were found to be a possible cause of failure.
Surface modification of porous nanocrystalline TiO2 films for dye-sensitized solar cell application by various gas plasmas
Authors: Kim Youngsoo , Yoon Chang-Ho , Kim Kang-Jin , Lee Yeonhee
Published: July 2007

Titanium dioxide (TiO2) film for dye-sensitized solar cells (DSSCs) has surface defects such as oxygen vacancies created during the annealing process. The authors used a plasma treatment technique to reduce defects on TiO2 surfaces. They investigated the influence of different gas plasma treatments of TiO2 film on the photoelectric performance of DSSC. Short-circuit photocurrent density (Jsc), open-circuit photovoltage (Voc), and the amount of adsorbed dye for DSSCs were measured. As a result, the solar-to-electricity conversion efficiencies of the O2- and N2-treated cells increased by 15%–20% compared to untreated cells. On the other hand, solar energy conversion efficiency of CF4-plasma treated cells decreased drastically. The increased amount of adsorbed dye on the TiO2 film was measured by time-of-flight secondary ion mass spectrometry. TiO2 surfaces modified by plasma treatment were characterized using analytical instruments such as x-ray photoelectron spectroscopy and near-edge x-ray absorption fine structure.
Oxygen plasma treatment and deposition of CNx on a fluorinated polymer matrix composite for improved erosion resistance
Authors: Muratore C. , Korenyi-Both A. , Bultman J. E. , Waite A. R. , Jones J. G. , Storage T. M. , Voevodin A. A.
Published: July 2007

The use of polymer matrix composites in aerospace propulsion applications is currently limited by insufficient resistance to erosion by abrasive media. Erosion resistant coatings may provide necessary protection; however, adhesion to many high temperature polymer matrix composite (PMC) materials is poor. A low pressure oxygen plasma treatment process was developed to improve adhesion of CNx coatings to a carbon reinforced, fluorinated polymer matrix composite. Fullerene-like CNx was selected as an erosion resistant coating for its high hardness-to-elastic modulus ratio and elastic resilience which were expected to reduce erosion from media incident at different angles (normal or glancing) relative to the surface. In situ x-ray photoelectron spectroscopy was used to evaluate the effect of the plasma treatment on surface chemistry, and electron microscopy was used to identify changes in the surface morphology of the PMC substrate after plasma exposure. The fluorine concentration at the surface was significantly reduced and the carbon fibers were exposed after plasma treatment. CNx coatings were then deposited on oxygen treated PMC substrates. Qualitative tests demonstrated that plasma treatment improved coating adhesion resulting in an erosion resistance improvement of a factor of 2 compared to untreated coated composite substrates. The combination of PMC pretreatment and coating with CNx reduced the erosion rate by an order of magnitude for normally incident particles.
Vacuum systems for the ILC helical undulator
Authors: Malyshev O. B. , Scott D. J. , Bailey I. R. , Barber D. P. , Baynham E. , Bradshaw T. , Brummitt A. , Carr S. , Clarke J. A. , Cooke P. , Dainton J. B. , Ivanyushenkov Y. , Malysheva L. I. , Moortgat-Pick G. A. , Rochford J.
Published: July 2007

The International Linear Collider (ILC) positron source uses a helical undulator to generate polarized photons of ∼10MeV at the first harmonic. Unlike many undulators used in synchrotron radiation sources, the ILC helical undulator vacuum chamber will be bombarded by photons, generated by the undulator, with energies mostly below that of the first harmonic. Achieving the vacuum specification of ∼100nTorr in a narrow chamber of 4–6mm inner diameter, with a long length of 100–200m, makes the design of the vacuum system challenging. This article describes the vacuum specifications and calculations of the flux and energy of photons irradiating the undulator vacuum chamber and considers possible vacuum system design solutions for two cases: cryogenic and room temperature.
Surface modification of SKD-61 steel by ion implantation technique
Authors: Wen F. L. , Lo Y.-L. , Yu Y.-C.
Published: July 2007

The purpose of this study is to investigate how ion implantation affects the surface characteristics and nitrogenizing depth of the thin film by the use of a NEC 9SDH-2 3MV Pelletron accelerator that implants nitrogen ions into SKD-61 tool steels for surface modification. Nitrogen ions were implanted into the surface layer of materials so that the hardness of modified films could be improved. Also, the nitride film stripping problems of the traditional nitrogenizing treatment could be overcome by a new approach in surface process engineering. As nitrogen ions with high velocity impacted on the surface of the substrate, the ions were absorbed and accumulated on the surface of the substrate. The experiments were performed with two energies (i.e., 1 and 2MeV) and different doses (i.e., 2.5×1015, 7.5×1015, and 1.5×1016ions∕cm2). Nitrogen ions were incorporated into the interface and then diffused through the metal to form a nitride layer. Analysis tools included the calculation of stopping and range of ions in matter (SRIM), the detection of a secondary ion mass spectrometry (SIMS), and nanoindentation testing. Through the depth analysis of SIMS, the effects of the ion-implanted SKD-61 steels after heating at 550°C in a vacuum furnace were examined. The nanoindenting results indicate the variation of hardness of SKD-61 steels with the various ion doses. It reaches two to three times the original hardness of SKD-61 steels.
Sublimation behavior of SiO2 from low- and high-index silicon surfaces
Authors: Moore J. C. , Skrobiszewski J. L. , Baski A. A.
Published: July 2007

The authors have used atomic force microscopy to investigate the sublimation behavior of 100-nm-thick oxide layers from the low-index Si(001) and Si(111) surfaces, as well as the stable, high-index Si(113) and Si(5 5 12) surfaces. Similar to previous thin-film (<50nm) sublimation studies, high vacuum annealing results in the formation of circular voids that grow laterally with annealing time (1–6min, 1150–1350°C). The depth of these voids is ∼200nm, or twice the thickness of the original oxide film, which is consistent with the thermal decomposition of SiO2 to form volatile SiO. There are subtle morphological differences, however, between the voids formed on the different surface orientations. Line profiles of the bottom Si surfaces inside the voids indicate flat terraces for the (111) and (113) orientations and sloped conic sections for the (001) and (5 5 12) orientations, indicating that the latter surfaces are less stable with respect to step formation during oxide sublimation. At the centers of voids, features such as deep pits (5μm diameter, 200–700nm depth) or vertical structures (1μm diameter, up to 700nm height) are present. Deep depressions are also observed at vertical sidewalls that occur during sequential anneals or on a patterned surface. After the thick oxide is completely desorbed, an undulating surface morphology occurs on all surface orientations due to the coalescence of the void sidewalls.
TM01-mode microwave propagation property analysis for plasmas with disk-plate windows by a finite-difference time-domain method
Authors: Okamura Yoshimasa , Yamamoto Yoshito , Fujita Kazuhiro , Miyoshi Taiki , Teramoto Koji , Kawaguchi Hideki , Kagami Shin , Furukawa Masakazu
Published: July 2007

Numerical studies of microwave propagation properties in a conical horn and an adjustable waveguides, and for plasmas generated under disk-plate windows of a 220mm diameter and in a vacuum chamber are studied by a finite-difference time-domain (FDTD) method including plasma equations. In the numerical studies, a TM01-mode microwave of 2.45GHz at a power of 1kW is supplied from the top of the conical horn waveguide. In addition, numerical results by the FDTD method are compared with experimental results, and a validity of the numerical results is investigated. From the numerical results, it is found that the TM01-mode microwave changes its field shape and propagates along inner surfaces of the conical horn and the adjustable waveguides. Then electromagnetic fields of the TM01-mode microwave concentrate at the center surfaces of the disk-plate windows [quartz (εr=3.8), alumina (εr=9.7), and WG20 (εr=20.0)]. A diameter of higher concentration is within 80mm, and the orientation of electric field is almost vertical to the disk-plate window. The diameters within 80mm are equivalent to a diameter at a higher electron density in an oxygen plasma experiment in the volume mode at 1kW and 133Pa with a quartz window. When heights of the adjustable waveguide are changed from 64to244mm, peaks of electric fields in the heights, where microwave power is estimated to be strongly absorbed into the plasmas, appear and peak positions of the electric fields are observed periodically in surface-wave mode plasmas as well as the volume mode plasmas. Heights of the peaks increase with increasing dielectric constant and peak-to-peak distances of the peak positions decrease with increasing dielectric constant. The peak positions agree to the minimum microwave power reflections tuned by a combination of an autotuning unit and adjustable waveguide heights in experiments. Furthermore, peak positions of relatively absorbed microwave powers in the surface-wave and volume mode plasmas calculated by Poynting vectors in the FDTD method are close to the peak positions. This means that microwave powers penetrate effectively the disk-plate windows near the peak positions. In addition, a relatively absorbed microwave power with an alumina disk-plate window (surface-wave mode plasma) is larger than that with the quartz disk-plate window (volume mode plasma). This comes from a reason that a larger electron density in the surface-wave plasma absorbs a larger quantity of the microwave power. From the above comparisons between results obtained by the FDTD method and experiments, a validity of the FDTD method including the plasma equations can be confirmed.
Cloning, Nucleotide Sequencing, and Analysis of the AcrAB-TolC Efflux Pump of
Enterobacter cloacae
and Determination of Its Involvement in Antibiotic Resistance in a Clinical Isolate
Authors: Pérez Astrid , Canle Delia , Latasa Cristina , Poza Margarita , Beceiro Alejandro , del Mar Tomás María , Fernández Ana , Mallo Susana , Pérez Sonia , Molina Francisca , Villanueva Rosa , Lasa Iñigo , Bou Germán
Published: July 2007

Enterobacter cloacae
is an emerging clinical pathogen that may be responsible for nosocomial infections. Management of these infections is often difficult, owing to the high frequency of strains that are resistant to disinfectants and antimicrobial agents in the clinical setting. Multidrug efflux pumps, especially those belonging to the resistance-nodulation-division family, play a major role as a mechanism of antimicrobial resistance in gram-negative pathogens. In the present study, we cloned and sequenced the genes encoding an AcrAcB-TolC-like efflux pump from an
E. cloacae
clinical isolate (isolate EcDC64) showing a broad antibiotic resistance profile. Sequence analysis showed that the
acrR, acrA, acrB
, and
tolC
genes encode proteins that display 79.8%, 84%, 88%, and 82% amino acid identities with the respective homologues of
Enterobacter aerogenes
and are arranged in a similar pattern. Deletion of the
acrA
gene to yield an AcrA-deficient EcDC64 mutant (EcΔacrA) showed the involvement of AcrAB-TolC in multidrug resistance in
E. cloacae
. However, experiments with an efflux pump inhibitor suggested that additional efflux systems also play a role in antibiotic resistance. Investigation of several unrelated isolates of
E. cloacae
by PCR analysis revealed that the AcrAB system is apparently ubiquitous in this species.
In Vitro Antiviral Activity and Cross-Resistance Profile of PL-100, a Novel Protease Inhibitor of Human Immunodeficiency Virus Type 1
Authors: Dandache Serge , Sévigny Guy , Yelle Jocelyn , Stranix Brent R. , Parkin Neil , Schapiro Jonathan M. , Wainberg Mark A. , Wu Jinzi J.
Published: July 2007

Despite the success of highly active antiretroviral therapy, the current emergence and spread of drug-resistant variants of human immunodeficiency virus (HIV) stress the need for new inhibitors with distinct properties. We designed, produced, and screened a library of compounds based on an original
l
-lysine scaffold for their potentials as HIV type 1 (HIV-1) protease inhibitors (PI). One candidate compound, PL-100, emerged as a specific and noncytotoxic PI that exhibited potent inhibition of HIV-1 protease and viral replication in vitro (

K
i

, ∼36 pM, and 50% effective concentration [EC
50
], ∼16 nM, respectively). To confirm that PL-100 possessed a favorable resistance profile, we performed a cross-resistance study using a panel of 63 viral strains from PI-experienced patients selected for the presence of primary PI mutations known to confer resistance to multiple PIs now in clinical use. The results showed that PL-100 retained excellent antiviral activity against almost all of these PI-resistant viruses and that its performance in this regard was superior to those of atazanavir, amprenavir, indinavir, lopinavir, nelfinavir, and saquinavir. In almost every case, the increase in the EC
50
for PL-100 observed with viruses containing multiple mutations in protease was far less than that obtained with the other drugs tested. These data underscore the potential for PL-100 to be used in the treatment of drug-resistant HIV disease and argue for its further development.
Phase I and II Study of the Safety, Virologic Effect, and Pharmacokinetics/Pharmacodynamics of Single-Dose 3-O-(3′,3′-Dimethylsuccinyl)Betulinic Acid (Bevirimat) against Human Immunodeficiency Virus Infection
Authors: Smith Patrick F. , Ogundele Abayomi , Forrest Alan , Wilton John , Salzwedel Karl , Doto Judy , Allaway Graham P. , Martin David E.
Published: July 2007

Bevirimat [3-O-(3′,3′-dimethylsuccinyl)betulinic acid] is the first in a new class of anti-human immunodeficiency virus (HIV) drugs that inhibit viral maturation by specifically blocking cleavage of the Gag capsid (CA) precursor, CA-SP1, to mature CA protein, resulting in defective core condensation and release of immature noninfectious virions. Four cohorts of six HIV-infected adults, with CD4 counts of >200 and plasma viral loads of 5,000 to 250,000 transcripts/ml and not currently receiving antiretroviral therapy, were randomized to receive a single oral dose of placebo, 75, 150, or 250 mg of bevirimat. Thirty blood samples for drug concentrations and 20 HIV RNA measures were collected from each subject over a 20-day period. Candidate pharmacokinetic/pharmacodynamic models were fit to individual subjects by maximum likelihood followed by Bayesian estimation; model discrimination was by corrected Akaike's Information Criterion. The bevirimat pharmacokinetics was well described by an oral two-compartment linear model (r2, 0.98), with a mean (percent coefficient of variation) half-life of 60.3 (13.6) h and apparent oral clearance of bevirimat from the plasma compartment of 0.17 (18) liters/h. HIV RNA was modeled as being produced in infected CD4 cells, with bevirimat inhibiting infection of new CD4 cells thru a Hill-type function (r2, 0.87). Single oral doses of bevirimat were well tolerated and demonstrated a dose-dependent reduction in viral load. The average maximum reduction from baseline following the 150- and 250-mg doses was greater than 0.45 log10, with individual patients having reductions of greater than 0.7 log10. No bevirimat resistance mutations were detected during the course of the study.
Innate Protection of
Mycobacterium smegmatis
against the Antimicrobial Activity of Nitric Oxide Is Provided by Mycothiol
Authors: Miller Christopher C. , Rawat Mamta , Johnson Todd , Av-Gay Yossef
Published: July 2007

Nitric oxide (NO) is an efficient antimicrobial agent. A role for mycothiol in protecting mycobacteria from nitrosative damage was revealed by showing that a
Mycobacterium smegmatis
mutant is sensitive to NO. A direct correlation between NO and mycothiol levels confirmed that mycothiol is important for protecting mycobacteria from NO attack.
Functional Consequences of Sequence Variation in Bundlin, the Enteropathogenic
Escherichia coli
Type IV Pilin Protein
Authors: Fernandes Paula J. , Guo Qin , Donnenberg Michael S.
Published: July 2007

The bundle-forming pilus (BFP) of enteropathogenic
Escherichia coli
(EPEC) is an important virulence factor. We examined the role of divergent alleles of
bfpA
encoding bundlin, the BFP pilin protein, in pilus biogenesis, pilus interactions, and immune responses. We found that the BFP biogenesis machine from an EPEC strain that expresses one bundlin type is capable of assembling all other bundlin types. Furthermore, we found that EPEC strains expressing divergent bundlin types are capable of forming mixed autoaggregates, suggesting that different pilin types can intertwine. However, we found that there was a marked difference between alleles in immunogenicity in both rabbits and mice of a peptide derived from a region of bundlin undergoing apparent diversifying selection. In addition, despite a high degree of cross-reactivity between divergent bundlin proteins, in both mice and rabbits responses appeared to be stronger against the homologous pilin protein than against the heterologous protein. This result was verified using sera from a volunteer study, which demonstrated that the human antibody responses after an initial challenge with live EPEC were stronger against the homologous bundlin protein than against a divergent bundlin protein. However, a repeat challenge induced equivalent responses. These results are consistent with the hypothesis that human immune responses against bundlin exert selective pressure on
bfpA
sequence divergence.
Differential CD28 and Inducible Costimulatory Molecule Signaling Requirements for Protective CD4+T-Cell-Mediated Immunity against Genital TractChlamydia trachomatisInfection
Authors: Marks Ellen , Verolin Martina , Stensson Anneli , Lycke Nils
Published: July 2007

Th1 cells and gamma interferon (IFN-γ) production play critical roles in protective immunity against genital tract infections byChlamydia trachomatis. Here we show that inducible costimulatory molecule (ICOS)−/−mice develop greatly augmented host resistance against chlamydial infection. Protection following a primary infection was characterized by strong Th1 immunity with enhanced CD4+T-cell-mediated IFN-γ production in the genital tract and high expression of T-bet in the draining para-aortic lymph node. This Th1 dominance was associated with low expression of interleukin 10 (IL-10) mRNA in the uteruses of protected ICOS−/−mice. By contrast, CD28−/−mice were severely impaired in their adaptive immune response, demonstrating a lack of CD4+T cells and IFN-γ in the genital tract, with a substantial delay in bacterial elimination compared to that seen in wild-type (WT) mice. Upon reinfection, WT mice exhibited a transient local infection with evidence of regulatory T-cell (Treg)/Foxp3 mRNA and a more balanced Th1 and Th2 response in the genital tract than ICOS−/−mice, whereas 90% of the latter mice developed sterile immunity, poor expression of local Treg/Foxp3 mRNA, and macroscopic signs of enhanced local immunopathology. Therefore, different requirements for CD28 signaling and ICOS signaling clearly apply to host protection against a genital tract infection byC. trachomatis. Whereas, CD28 signaling is critical, ICOS appears to be dispensable and can have a dampening effect on Th1 development by driving Th2 immunity and anti-inflammation through IL-10 production and promotion of the Foxp3+Treg populations in the genital tract. Both the CD28-deficient and the ICOS-deficient mice demonstrated poor specific antibody production, supporting the fact that antibodies are not needed for protection against genital tract chlamydial infections.