bluuebunny/crossref_metadata_2025 huggingface dataset:
Infectious Bronchitis Viruses with a Novel Genomic Organization
Authors: Mardani Karim , Noormohammadi Amir H. , Hooper Peter , Ignjatovic Jagoda , Browning Glenn F.
Published: November 2007

A number of novel infectious bronchitis viruses (IBVs) were previously identified in commercial poultry in Australia, where they caused significant economic losses. Since there has been only limited characterization of these viruses, we investigated the genomic and phenotypic differences between these novel IBVs and other, classical IBVs. The 3′ 7.5 kb of the genomes of 17 Australian IBV strains were sequenced, and growth properties of 6 of the strains were compared. Comparison of sequences of the genes coding for structural and nonstructural proteins revealed the existence of two IBV genotypes: classical and novel. The genomic organization of the classical IBVs was typical of those of other group III coronaviruses: 5′-Pol-S-3a-3b-E-M-5a-5b-N-untranslated region (UTR)-3′. However, the novel IBV genotype lacked either all or most of the genes coding for nonstructural proteins at the 3′ end of the genome and had a unique open reading frame, X1. The gene order was either 5′-Pol-S-X1-E-M-N-UTR-3′ or 5′-Pol-S-X1-E-M-5b-N-UTR-3′. Phenotypically, novel and classical IBVs also differed; novel IBVs grew at a slower rate and reached lower titers in vitro and in vivo and were markedly less immunogenic in chicks. Although the novel IBVs induced histopathological lesions in the tracheas of infected chicks that were comparable to those induced by classical strains, they did not induce lesions in the kidneys. This study has demonstrated for the first time the existence of a naturally occurring IBV genotype devoid of some of the genes coding for nonstructural proteins and has also indicated that all of the accessory genes are dispensable for the growth of IBV and that such viruses are able to cause clinical disease and economic loss. The phylogenic differences between these novel IBVs and other avian coronaviruses suggest a reservoir host distinct from domestic poultry.
Adeno-Associated Virus Type 12 (AAV12): a Novel AAV Serotype with Sialic Acid- and Heparan Sulfate Proteoglycan-Independent Transduction Activity
Authors: Schmidt Michael , Voutetakis Antonis , Afione Sandra , Zheng Changyu , Mandikian Danielle , Chiorini John A.
Published: November 2007

Recombinant adeno-associated virus (rAAV) is a promising vector for gene therapy. Recent isolations of novel AAV serotypes have led to significant advances by broadening the tropism and increasing the efficiency of gene transfer to the desired target cell. However, a major concern that remains is the strong preexisting immune responses to several vectors. In this paper, we describe the isolation and characterization of AAV12, an AAV serotype with unique biological and immunological properties. In contrast to those of all other reported AAVs, AAV12 cell attachment and transduction do not require cell surface sialic acids or heparan sulfate proteoglycans. Furthermore, rAAV12 is resistant to neutralization by circulating antibodies from human serum. The feasibility of rAAV12 as a vector was demonstrated in a mouse model in which muscle and salivary glands were transduced. These characteristics make rAAV12 an interesting candidate for gene transfer applications.
Mortality of former crocidolite (blue asbestos) miners and millers at Wittenoom: Table 1
Authors: Musk A W , de Klerk N H , Reid A , Ambrosini G L , Fritschi L , Olsen N J , Merler E , Hobbs M S T , Berry G
Published: November 2007

Background:

Blue asbestos was mined and milled at Wittenoom in Western Australia between 1943 and 1966.

Methods:

Nearly 7000 male workers who worked at the Wittenoom mine and mill have been followed up using death and cancer registries throughout Australia and Italy to the end of 2000. Person-years at risk were derived using two censoring dates in order to produce minimum and maximum estimates of asbestos effect. Standardised mortality ratios (SMRs) compare the mortality of the former Wittenoom workers with the Western Australian male population.

Results:

There have been 190 cases of pleural and 32 cases of peritoneal mesothelioma in this cohort of former workers at Wittenoom. Mortality from lung cancer (SMR = 1.52), pneumoconiosis (SMR = 15.5), respiratory diseases (SMR = 1.58), tuberculosis (SMR = 3.06), digestive diseases (SMR = 1.47), alcoholism (SMR = 2.24) and symptoms, signs and ill defined conditions (SMR = 2.00) were greater in this cohort compared to the Western Australian male population.

Conclusion:

Asbestos related diseases, particularly malignant mesothelioma, lung cancer and pneumoconiosis, continue to be the main causes of excess mortality in the former blue asbestos miners and millers of Wittenoom.
Work stress and health in primary health care physicians and hospital physicians
Authors: Virtanen P , Oksanen T , Kivimäki M , Virtanen M , Pentti J , Vahtera J
Published: November 2007

Objective:

In order to understand the reasons for the low priority given to work in primary health care among physicians, we studied differences in work stress, health and health related lifestyles between general practitioners (GPs) and hospital physicians.

Method:

A cohort of 226 GPs and 523 consultants from Finland responded to a questionnaire survey. The responses were linked to data on registered sickness absence.

Results:

Compared with consultants, GPs reported higher job strain (OR 1.76, 95% CI 1.23 to 2.53) and perceived work overload (OR 2.29, 95% CI 1.65 to 3.16) but were less likely to report poor team climate (OR 0.65, 95% CI 0.46 to 0.91), procedural injustice (OR 0.49, 95% CI 0.34 to 0.72) and interactional injustice (OR 0.62, 95% CI 0.44 to 0.88). There were only small differences in lifestyle, perceived health, psychological distress and long sick leaves between GPs and consultants. Short sick leaves were more common among GPs, but this difference disappeared after controlling for work characteristics.

Conclusion:

In relation to the current recruitment crisis in primary health care and the studied working conditions, job strain and heavy workload outweigh the attractiveness of a good working climate and low organisational injustice. The non-significant differences in health may indicate that there are no differences in total work stress between GPs and consultants. In tackling the recruitment problems in the field of health care, it is of particular importance to be aware of the sector specific difficulties in working conditions.
Do state characteristics matter? State level factors related to tobacco cessation quitlines
Authors: Keller Paula A , Koss Kalsea J , Baker Timothy B , Bailey Linda A , Fiore Michael C
Published: November 2007

Background:

Quitline services are an effective population-wide tobacco cessation strategy adopted widely in the United States as part of state comprehensive tobacco control efforts. Despite widespread evidence supporting quitlines’ effectiveness, many states lack sufficient financial resources to adequately fund and promote this service. Efforts to augment state tobacco control efforts might be fostered by greater knowledge of state level factors associated with the funding and implementation of those efforts.

Methods:

We analysed data from the 2004 North American Quitline Consortium survey and from publicly available sources to identify state level factors related to quitline implementation and funding. Factors included in the analyses were state demographic characteristics, tobacco use variables, state tobacco control spending, and economic and political climate variables. Univariate and multivariate regression analyses were conducted.

Results:

The best fitting multivariate model that significantly predicted the presence or absence of a state quitline included only cigarette excise tax rate (p = 0.020). In terms of funding levels, states with high rates of cigarette consumption (p = 0.047) and with higher per capita expenditures for tobacco control programmes (p = 0 .0.004) were most likely to spend more on per capita operations budget for quitlines.

Conclusion:

State level factors appear to play a part in whether states had established quitlines by mid-2004 and the amount of per capita quitline funding.
The effectiveness and cost effectiveness of telephone counselling and the nicotine patch in a state tobacco quitline
Authors: Hollis Jack F , McAfee Timothy A , Fellows Jeffrey L , Zbikowski Susan M , Stark Michael , Riedlinger Karen
Published: November 2007

Objectives:

State and national tobacco quitlines have expanded rapidly and offer a range of services. We examined the effectiveness and cost effectiveness of offering callers single session versus multisession counselling, with or without free nicotine patches.

Methods:

This 3×2 randomised trial included 4614 Oregon tobacco quitline callers and compared brief (one 15-minute call), moderate (one 30-minute call and a follow-up call) and intensive (five proactive calls) intervention protocols, with or without offers of free nicotine patches (nicotine replacement therapy, NRT). Blinded staff assessed tobacco use by phone at 12 months.

Results:

Abstinence odds ratios were significant for moderate (OR = 1.22, CI = 1.01 to 1.48) and intensive (OR = 1.29, CI = 1.07 to 1.56) intervention, and for NRT (OR = 1.58, CI = 1.35 to 1.85). Intent to treat quit rates were as follows: brief no NRT (12%); brief NRT (17%); moderate no NRT (14%); moderate NRT (20%); intensive no NRT (14%); and intensive NRT (21%). Relative to brief no NRT, the added costs for each additional quit was $2467 for brief NRT, $1912 for moderate no NRT, $2109 for moderate NRT, $2641 for intensive no NRT, and $2112 for intensive NRT.

Conclusion:

Offering free NRT and multisession telephone support within a state tobacco quitline led to higher quit rates, and similar costs per incremental quit, than less intensive protocols.
Cost effectiveness of the Oregon quitline “free patch initiative”
Authors: Fellows Jeffrey L , Bush Terry , McAfee Tim , Dickerson John
Published: November 2007

Objective:

We estimated the cost effectiveness of the Oregon tobacco quitline’s “free patch initiative” compared to the pre-initiative programme.

Methods:

Using quitline utilisation and cost data from the state, intervention providers and patients, we estimated annual programme use and costs for media promotions and intervention services. We also estimated annual quitline registration calls and the number of quitters and life years saved for the pre-initiative and free patch initiative programmes. Service utilisation and 30-day abstinence at six months were obtained from 959 quitline callers. We compared the cost effectiveness of the free patch initiative (media and intervention costs) to the pre-initiative service offered to insured and uninsured callers. We conducted sensitivity analyses on key programme costs and outcomes by estimating a best case and worst case scenario for each intervention strategy.

Results:

Compared to the pre-intervention programme, the free patch initiative doubled registered calls, increased quitting fourfold and reduced total costs per quit by $2688. We estimated annual paid media costs were $215 per registered tobacco user for the pre-initiative programme and less than $4 per caller during the free patch initiative. Compared to the pre-initiative programme, incremental quitline promotion and intervention costs for the free patch initiative were $86 (range $22–$353) per life year saved.

Conclusions:

Compared to the pre-initiative programme, the free patch initiative was a highly cost effective strategy for increasing quitting in the population.
Effects of frequency and duration in telephone counselling for smoking cessation: Table 1
Authors: Rabius V , Pike K J , Hunter J , Wiatrek D , McAlister A L
Published: November 2007

Objective:

This study evaluates alternative protocols in telephone counselling for smoking cessation.

Design:

The American Cancer Society enrolled 6322 clients in a randomised trial comparing three counselling formats of varying duration and frequency of contact, with or without booster sessions, and mailed self help booklets without telephone counselling.

Setting and participants:

Participants were drawn from callers to the American Cancer Society’s National Cancer Information Center seeking assistance with smoking cessation who provided informed consent and were adult daily smokers, ready to make a quit attempt within two weeks, and from states not served by an evidence based proactive telephone counselling programme.

Outcomes:

Six-month cessation rates (30-day point prevalence) were measured in telephone interviews.

Results:

There was a significant counselling effect. The overall cessation rates that were yielded by a brief protocol including booster sessions were equivalent to those obtained with the American Cancer Society’s standard protocol with boosters.

Conclusions:

Based on these findings, the abbreviated protocol with five sessions and two boosters is considered to be an option for improving cost efficiency in the delivery of this service.
Effectiveness and cost effectiveness of television, radio and print advertisements in promoting the New York smokers’ quitline: Table 1
Authors: Farrelly Matthew C , Hussin Altijani , Bauer Ursula E
Published: November 2007

Objectives:

This study assessed the relative effectiveness and cost effectiveness of television, radio and print advertisements to generate calls to the New York smokers’ quitline.

Methods:

Regression analysis was used to link total county level monthly quitline calls to television, radio and print advertising expenditures. Based on regression results, standardised measures of the relative effectiveness and cost effectiveness of expenditures were computed.

Results:

There was a positive and statistically significant relation between call volume and expenditures for television (p<0.01) and radio (p<0.001) advertisements and a marginally significant effect for expenditures on newspaper advertisements (p<0.065). The largest effect was for television advertising. However, because of differences in advertising costs, for every $1000 increase in television, radio and newspaper expenditures, call volume increased by 0.1%, 5.7% and 2.8%, respectively.

Conclusions:

Television, radio and print media all effectively increased calls to the New York smokers’ quitline. Although increases in expenditures for television were the most effective, their relatively high costs suggest they are not currently the most cost effective means to promote a quitline. This implies that a more efficient mix of media would place greater emphasis on radio than television. However, because the current study does not adequately assess the extent to which radio expenditures would sustain their effectiveness with substantial expenditure increases, it is not feasible to determine a more optimal mix of expenditures.
Expanding access to nicotine replacement therapy through Minnesota’s QUITLINE partnership: Table 1
Authors: Schillo Barbara A , Wendling Ann , Saul Jessie , Luxenberg Michael G , Lachter Randi , Christenson Matthew , An Lawrence C
Published: November 2007

Background:

Partnerships can expand the reach and effectiveness of quitlines while conserving limited tobacco control dollars.

Objective:

To describe how the addition of free nicotine replacement therapy (NRT) to the “QUITPLAN Helpline” in Minnesota influenced triage and transfer to health plan quitlines and how efforts taken to re-establish balance in the partnership expanded population based access to NRT.

Methods:

NRT provision began in September 2002. Call volumes, transfer rates and ClearWay Minnesota dollars spent serving health plan members were examined from May 2001 through November 2005. The process by which health plan quitlines began providing NRT as a result of the addition of NRT to the QUITPLAN Helpline in September 2002 was explored through interviews with health plan representatives.

Results:

Following the addition of NRT to the QUITPLAN Helpline, the percentage of health plan members transferred to their health plans decreased because callers were resisting transfer to their health plans for telephone counselling that did not include NRT. Transfer rates eventually returned to pre-NRT levels following sequential implementation of scripting changes, transfer requirements and collection of health plan identification numbers. These changes reduced ClearWay Minnesota dollars spent on providing services to insured Minnesotans. Through the partnership, all Minnesotans currently have access to both telephone counselling and NRT either at no or low cost.

Conclusions:

Minnesota’s partnership has effectively expanded access to NRT through quitlines. The increased use of partnerships for providing quitline services may be effective in broadening population access while conserving limited tobacco control dollars for those without cessation benefits.
Comprehensive smoke-free legislation in England: how advocacy won the day: Table 1
Authors: Arnott Deborah , Dockrell Martin , Sandford Amanda , Willmore Ian
Published: November 2007

Objective:

To examine how a government committed to a voluntary approach was forced by an effective advocacy coalition to introduce comprehensive smoke-free legislation.

Methods:

A diary was kept from the start of the campaign in 2003, backed up by journal and press articles, and information downloaded from the web. Regular public opinion polls were also carried out to supplement government surveys and polls conducted by the media.

Results:

The 1997 Labour Government was committed to a voluntary approach to deal with the problem of secondhand smoke. By 2003, efforts to persuade government to introduce regulation of workplace secondhand smoke through a health and safety code of practice with exemptions for the hospitality trade, had failed. Despite a lack of support from the government, including the health minister, a new strategy by health advocates focusing on comprehensive workplace legislation was able to succeed.

Conclusions:

In a democracy it is crucial to develop public knowledge and belief in the extent of the risks of secondhand smoke. Gaining public and media support for the issue can ensure that government has to take action and that the legislation will be enforceable. The interests of the tobacco industry and the hospitality trade differ and this can be used to gain hospitality trade support for comprehensive national legislation in order to ensure a level playing field and protection from litigation.
Tobacco cessation quitlines in North America: a descriptive study
Authors: Cummins Sharon E , Bailey Linda , Campbell Sharon , Koon-Kirby Carrie , Zhu Shu-Hong
Published: November 2007

Background:

Quitlines have become an integral part of tobacco control efforts in the United States and Canada. The demonstrated efficacy and the convenience of telephone based counselling have led to the fast adoption of quitlines, to the point of near universal access in North America. However, information on how these quitlines operate in actual practice is not often readily available.

Objectives:

This study describes quitline practice in North America and examines commonalities and differences across quitlines. It will serve as a source of reference for practitioners and researchers, with the aim of furthering service quality and promoting continued innovation.

Design:

A self administered questionnaire survey of large, publicly funded quitlines in the United States and Canada. A total of 52 US quitlines and 10 Canadian quitlines participated. Descriptive statistics are provided regarding quitline operational structures, clinical services, quality assurance procedures, funding sources and utilisation rates.

Results:

Clinical services for the 62 state/provincial quitlines are supplied by a total of 26 service providers. Nine providers operate multiple quitlines, creating greater consistency in operation than would otherwise be expected. Most quitlines offer services over extended hours (mean 96 hours/week) and have multiple language capabilities. Most (98%) use proactive multisession counselling—a key feature of protocols tested in previous experimental trials. Almost all quitlines have extensive training programmes (>60 hours) for counselling staff, and over 70% conduct regular evaluation of outcomes. About half of quitlines use the internet to provide cessation information. A little over a third of US quitlines distribute free cessation medications to eligible callers. The average utilisation rate of the US state quitlines in the 2004–5 fiscal year was about 1.0% across states, with a strong correlation between the funding level of the quitlines and the smokers’ utilisation of them (r = 0.74, p<0.001).

Conclusions:

Quitlines in North America display core commonalities: they have adopted the principles of multisession proactive counselling and they conduct regular outcome evaluation. Yet variations, tested and untested, exist. Standardised reporting procedures would be of benefit to the field. Shared discussion of the rationale behind variations can inform future decision making for all North American quitlines.
Smokers’ acceptance of “cold calls” offering quitline services: Table 1
Authors: Van Deusen Amy M , Hyland Andrew , Abrams Sara M , Celestino Paula , Mahoney Martin C , Cummings K Michael
Published: November 2007

Objective:

A random sample of smokers was offered a transfer to the New York State Smokers’ Quitline in order to assess smokers’ acceptance of “cold calls” offering quitline services.

Method:

A 30-minute survey to assess adult tobacco use was administered to 121 western New York smokers who were originally sampled for a random digit dialled survey in 2005, and then re-interviewed one year later, between April and July 2006. Smokers’ interest in receiving immediate quitline assistance was assessed at the end of the survey, when the smokers could choose to be transferred to the New York State Smokers’ Quitline in order to receive the quitline’s cessation services.

Results:

41% of smokers accepted the offer for, and subsequently received, New York State Smokers’ Quitline services. After controlling for factors related to cessation, women were more likely to respond to the offer.

Conclusions:

Although telephone quitline utilisation is low, these data suggest that the demand is high and “cold calls” may be a strategy to extend the use of quitline cessation services.
Tobacco quitlines: looking back and looking ahead: Figure 1
Authors: Anderson C M , Zhu S-H
Published: November 2007

Telephone based tobacco cessation services, or quitlines, have become central components of many comprehensive tobacco control programmes. This paper provides an overview of their history, noting milestones in the growth of quitlines. Key factors in their worldwide adoption were solid evidence from clinical trials with large community samples and strong backing from public health officials. Quitlines are now available throughout most of North America, Europe, Australia and in many other locations around the world. The paper also offers several recommendations for future directions in quitline practice and research. Benchmarks should be established for key areas of quitline implementation, such as accessibility, quality and cost efficiency. Advances in pharmacotherapy, telephony and web based applications should be investigated for opportunities to expand service offerings. Research and development are needed to determine how best to serve a diverse clientele in the most cost effective manner. Funding should be expanded and diversified to enable quitlines to serve much larger numbers of users. Healthcare providers should be targeted for quitline promotion, to engage them in a broad effort to increase the number of patients receiving cessation messages from clinicians. The goal of quitline promotion should expand to include an increase in unaided quit attempts in the population. Early research findings were quickly adopted in quitline practice, and future research to answer questions that have arisen through the implementation of quitlines will probably also find quick adoption.
Ultrafine particle emissions from waterpipes
Authors: Monn Ch , Kindler Ph , Meile A , Brändli O
Published: November 2007

Objectives:

Ultrafine particle emissions from waterpipes and their impact on human health have not been extensively studied. The aim of this study was to characterise the inhalation pattern of waterpipe smokers, and (a) construct apparatus to simulate waterpipe smoking in the laboratory, and (b) characterise mainstream emissions from waterpipes under different smoking conditions.

Methods:

Real life waterpipe smoking patterns were first measured with a spirometer. The average smoking pattern was then mechanically simulated in apparatus. Total particle number concentrations were determined with a condensation particle counter (CPC) for particles between 0.02 μm and 1 μm (P-Trak UPC, Model 8525, TSI) and the particle size fraction was determined with a differential mobility analyser (DMA) for particles from 0.01 μm to 0.5 μm. This instrument was coupled with a laser particle spectrometer for particles between 0.35 μm and 10 μm (Wide Range Particle Spectrometer, Model 1000XP, MSC Corp). Carbon monoxide levels were determined with an electrochemical sensor (Q-Trak monitor, Model 8554, TSI).

Results:

The tidal volume of an average waterpipe breath of 5 seconds was found to be 1 (SD 0.47) litre. The intervals between breaths on average were 25.5 (SD 10.2) seconds. Particle number concentrations of ultrafine particles in mainstream smoke during waterpipe smoking ranged up to 70×109particles per litre. The median diameter of the particles in a full smoking set with charcoal, tobacco and water was 0.04 μm. Smoke from the heated tobacco contributed to particles in the size range between 0.01 μm and 0.2 μm. The glowing piece of charcoal only contributed to particles smaller than 0.05 μm.

Conclusions:

Waterpipe smoking emits large amounts of ultrafine particles. With regard to particle emissions, smoking waterpipes may carry similar health risks to smoking cigarettes.
DYNAMIC LOCALIZATION AND ELECTROMAGNETIC TRANSPARENCY OF SEMICONDUCTOR SUPERLATTICE IN MULTIFREQUENCY ELECTRIC FIELDS
Authors: ROMANOVA J. Y. , ROMANOV Y. A.
Published: November 2007

We consider the dynamics of electrons in semiconductor superlattices in intense multifrequency electric fields. We examine the conditions for dynamic localization and electromagnetic transparency. We investigate processes of formation, destruction, and stabilization of electromagnetic transparency in biharmonic field. The stable states with static fields are determined.
DISSIPATIVE REGIME OF DYNAMIC LOCALIZATION IN DOUBLE QUANTUM DOT
Authors: BURDOV VLADIMIR A. , SOLENOV DMITRY
Published: November 2007

Dissipative electron dynamics in a double quantum dot, influenced by external ac and dc electric fields, has been analyzed. It was shown that the dissipation caused by phonon environment disappears under certain relations between electric field parameters. In this case one may perform the dynamic localization and form stable electron states localized within one of the dots.
OPTICAL SPECTROSCOPY OF 2D NANOISLANDS IN QUANTUM WELLS: LATERAL ISLAND PROFILES AND NATURE OF EMITTING STATES
Authors: REZNITSKY ALEXANDER , PERMOGOROV SERGEI , KLOCHIKHIN ALBERT , KALT HEINZ , KLINGSHIRN CLAUS
Published: November 2007

Results of experimental studies of photoluminescence (PL) and PL excitation (PLE) spectra of MBE grown single quantum wells (QWs) formed by insertion of few CdSe monolayers in the ZnSe matrix are reviewed. PL spectra of such quantum objects originate from the luminescence of CdSe -rich nanoislands. Two types of island emitting states, namely ground and metastable ones, contribute to the low- and high-energy parts of the PL band, respectively. An interplay between these contributions is responsible for the anomalous temperature dependence of the maximum position of the PL band. The optical orientation and optical alignment experiments at resonant excitations allow to elucidate the nature of the two types of the emitting states. PLE spectra of ground and metastable states have strongly differing characters at excitation below some characteristic energy E ME which is identified as the exciton percolation threshold. A theoretical model of the absorption spectra of emitting island states is presented, and practical applications of the model for the characterization of the island lateral concentration profiles are reported.
RECOMBINATION PROCESSES IN SYSTEMS BASED ON IONIC CRYSTALS WITH EMBEDDED SELF-ORGANIZED NANOCRYSTALS
Authors: ROMANOV N. G. , BADALYAN A. G. , TOLMACHEV D. O. , PREOBRAZHENSKI V. L. , BARANOV P. G. , NITSCH K. , POLAK K. , ROSA J.
Published: November 2007

The recombination processes leading to tunneling afterglow and photostimulated luminescence were studied in systems based on ionic host crystals with low-dimensional structures (semiconductor quantum dots) formed as a result of the self-organized growth. The systems of AgBr nanocrystals embedded into the KBr crystal lattice and CsPbBr 3 nanocrystals embedded into the CsBr crystal lattice were investigated. The energy of electron–hole recombination in matrices was shown to transfer to quantum dots. To identify the structure of recombining electron and hole centers, magnetic resonance detected optically by monitoring the tunneling afterglow was used.
GaSb/InGaAsSb/GaSb SINGLE AND MULTIPLE QUANTUM WELLS: OPTICAL PROPERTIES ENGINEERING AND APPLICATION
Authors: KOVALYOV A. A. , PCHELYAKOV O. P. , PREOBRAZHENSKII V. V. , PUTYATO M. M. , RUBTSOVA N. N. , SOROKIN E. , SOROKINA I. T.
Published: November 2007

MBE growth of GaSb / InGaAsSb / GaSb heterostructures of high crystal quality is performed under continual RHEED control. Transmission spectra of the films forming multiple quantum wells in λ ≈ 2–3 μm region confirm possibility to control optical properties of the structures through quantum confinement and through the content of semiconductor elements. New design of saturable absorption semiconductor mirror (SESAM) for Cr 2+: ZnSe laser is proposed and manufactured on the base of the single quantum well GaSb / InGaAsSb / GaSb placed between dielectric antireflection and broadband high reflection coatings.
TUNABLE 1D PHOTONIC CRYSTAL STRUCTURE BASED ON GROOVED Si INFILTRATED WITH LIQUID CRYSTAL E7
Authors: TOLMACHEV V. A. , ASTROVA E. V. , PILYUGINA J. A. , PEROVA T. S. , MOORE R. A.
Published: November 2007

Tuning of a photonic band gap (PBG) in a composite one-dimensional photonic crystal infiltrated with nematic liquid crystal (LC) E7 has been evaluated by simulations. It has been found that a sufficient shift of the short wave edge can be obtained only in structures with a pronounced initial alignment of a LC director in the grooves of a single crystalline Si matrix. The largest effect Δλedge = 0.52 μm is predicted for the reorientation of LC molecules from planar homogeneous alignment along the grooves to homeotropic alignment with respect to the Si walls due to an electro-optical effect. The shift in PBG due to thermal tuning resulting from the transition of LC from mesophase to the isotropic phase (Δλedge = 0.4 μm) is less than that due to electric tuning. Thermo-tuning has been demonstrated experimentally, and PBG shift as high as Δλedge = 0.25 μm has been achieved.
FORMATION OF SEMICONDUCTOR QUANTUM DOTS IN THE SUBCRITICAL THICKNESS RANGE
Authors: ALEXANDER TONKIKH , DUBROVSKII VLADIMIR , MUSIKHIN YURII , USTINOV VICTOR , CIRLIN GEORGE , POLYAKOV NIKOLAY , SAMSONENKO YURII , WERNER PETER
Published: November 2007

Formation of semiconductor quantum dots from a metastable wetting layer with the effective thickness well below the critical thickness is observed experimentally in the InAs / GaAs (100) and in the Ge / Si (100) systems. The observed effect is explained within the frame of the kinetic theory of quantum dot formation in mismatched heteroepitaxial systems.
III–V SEMICONDUCTOR SURFACE NANOPATTERNING USING ATOMIC FORCE MICROSCOPY FOR InAs QUANTUM DOT LOCALIZATION
Authors: TRANVOUEZ E. , DESCAMPS A. , BREMOND G. , TURALA A. , REGRENY P. , GENDRY M.
Published: November 2007

In order to create suitable nanoholes for quantum dot (QD) localization on InP and GaAs surfaces, we used atomic force microscopy in an intermittent contact mode coupled with a modulated voltage to realized local anodization at a nanometer scale. This method leads, after a few tens of milliseconds of oxidation, to an oxide height saturation and a low lateral growth rate for both surfaces. These specific results were used to control separately both the depth and the diameter of holes and to obtain compatible pattern for QD growth. We also demonstrated the thermal stability of these patterns at compatible temperatures with the InAs QD growth. First, results of QD growth on these patterns are presented.
PHOTOLUMINESCENCE OF NEAR-BRAGG MULTIPLE QUANTUM-WELL STRUCTURES
Authors: VORONOV M. M. , IVCHENKO E. L.
Published: November 2007

We report on a theoretical study of photoluminescence (PL) of the resonant one-dimensional photonic crystals, the near-Bragg quantum-well (QW) structures. The PL spectral intensity is found by including random sources in the equations for the exciton dielectric polarization and introducing the discrete Green function. The position and the width of peaks in the calculated PL spectra are in agreement with the real and imaginary parts of the exciton-polariton eigenfrequencies.
JOINT ACTION OF SPIN-TRANSFER AND SPIN-INJECTION TORQUES IN FERROMAGNETIC JUNCTIONS
Authors: EPSHTEIN ERNEST , GULYAEV YURI , ZILBERMAN PETER
Published: November 2007

We consider theoretically a current flowing perpendicular to interfaces of a spin-valve type ferromagnetic metallic junction. For the first time a simultaneous action of the two current effects is investigated, namely, the nonequilibrium longitudinal spin injection and the transverse spin surface torque. Dispersion relations for fluctuations are derived and solved under the proper boundary conditions. Joint action of the two effects mentioned lowers the instability threshold, its typical value being 1 × 106–3 × 107 A/cm2. Spin wave excitations may soften near the threshold. A nonlinear problem is solved about steady state arising due to instability development.
Increasing α7β1-integrin promotes muscle cell proliferation, adhesion, and resistance to apoptosis without changing gene expression
Authors: Liu Jianming , Burkin Dean J. , Kaufman Stephen J.
Published: November 2007

The dystrophin-glycoprotein complex maintains the integrity of skeletal muscle by associating laminin in the extracellular matrix with the actin cytoskeleton. Several human muscular dystrophies arise from defects in the components of this complex. The α7β1-integrin also binds laminin and links the extracellular matrix with the cytoskeleton. Enhancement of α7-integrin levels alleviates pathology in mdx/utrn−/− mice, a model of Duchenne muscular dystrophy, and thus the integrin may functionally compensate for the absence of dystrophin. To test whether increasing α7-integrin levels affects transcription and cellular functions, we generated α7-integrin-inducible C2C12 cells and transgenic mice that overexpress the integrin in skeletal muscle. C2C12 myoblasts with elevated levels of integrin exhibited increased adhesion to laminin, faster proliferation when serum was limited, resistance to staurosporine-induced apoptosis, and normal differentiation. Transgenic expression of eightfold more integrin in skeletal muscle did not result in notable toxic effects in vivo. Moreover, high levels of α7-integrin in both myoblasts and in skeletal muscle did not disrupt global gene expression profiles. Thus increasing integrin levels can compensate for defects in the extracellular matrix and cytoskeleton linkage caused by compromises in the dystrophin-glycoprotein complex without triggering apparent overt negative side effects. These results support the use of integrin enhancement as a therapy for muscular dystrophy.
Calcium/calmodulin-dependent kinase II mediates NO-elicited PKG activation to participate in spinal reflex potentiation in anesthetized rats
Authors: Chen Gin-Den , Peng Mei-Lin , Wang Pei-Yi , Lee Shin-Da , Chang Hung-Ming , Pan Shwu-Fen , Chen Mei-Jung , Tung Kwong-Chung , Lai Cheng-Yuan , Lin Tzer-Bin
Published: November 2007

Calcium/calmodulin protein kinase (CaMK)-dependent nitric oxide (NO) and the downstream intracellular messenger cGMP, which is activated by soluble guanylate cyclase (sGC), are believed to induce long-term changes in efficacy of synapses through the activation of protein kinase G (PKG). The aim of this study was to examine the involvement of the CaMKII-dependent NO/sGC/PKG pathway in a novel form of repetitive stimulation-induced spinal reflex potentiation (SRP). A single-pulse test stimulation (TS; 1/30 Hz) on the afferent nerve evoked a single action potential, while repetitive stimulation (RS; 1 Hz) induced a long-lasting SRP that was abolished by a selective Ca2+/CaMKII inhibitor, autocamtide 2-related inhibitory peptide (AIP). Such an inhibitory effect was reversed by a relative excess of nitric oxide synthase (NOS) substrate, l-arginine. In addition, the RS-induced SRP was abolished by pretreatment with the NOS inhibitor, NG-nitro-l-arginine-methyl ester (l-NAME). The sGC activator, protoporphyrin IX (PPIX), reversed the blocking effect caused by l-NAME. On the other hand, a sGC blocker, 1H-[1, 2, 4]oxadiazolo[4, 3-α]quinoxalin-1-one (ODQ), abolished the RS-induced SRP. Intrathecal applications of the membrane-permeable cGMP analog, 8-bromoguanosine 3′,5′-cyclic monophosphate sodium salt monohydrate (8-Br-cGMP), reversed the blocking effect on the RS-induced SRP elicited by the ODQ. Our findings suggest that a CaMKII-dependent NO/sGC/PKG pathway is involved in the RS-induced SRP, which has pathological relevance to hyperalgesia and allodynia.
In vivo regulation of AT1areceptor-mediated intracellular uptake of [125I]Val5-ANG II in the kidneys and adrenals of AT1areceptor-deficient mice
Authors: Li Xiao C. , Zhuo Jia L.
Published: November 2007

Using type 1a angiotensin receptor (AT1a) receptor-deficient (Agtr1a−/−) mice and in vivo autoradiography, we tested the hypothesis that intracellular uptake of ANG II in the kidney and adrenal glands is primarily mediated by AT1areceptors and that the response is regulated by prevailing endogenous ANG II. After pretreatment of wild-type (Agtr1a+/+) and Agtr1a−/− mice ( n = 6–9 each group) with or without captopril (25 mg·kg−1·day−1) or losartan (10 mg·kg−1·day−1) for 2 wk, [125I]Val5-ANG II was infused for 60 min. Intracellular uptake of [125I]Val5-ANG II was determined by quantitative in vivo autoradiography after washout of circulating [125I]Val5-ANG II. Basal intracellular ANG II levels were 65% lower in the kidney ( P < 0.001), but plasma ANG II levels were threefold higher, in Agtr1a−/− than wild-type mice ( P < 0.01). Although plasma [125I]Val5-ANG II levels were similar, urinary excretion of [125I]Val5-ANG II was fourfold higher in Agtr1a−/− mice ( P < 0.001). By contrast, intracellular [125I]Val5-ANG II levels were ∼80% lower in the kidney and adrenal glands of Agtr1a−/− mice ( P < 0.01). Captopril decreased endogenous plasma and renal ANG II levels ( P < 0.01) but increased intracellular uptake of [125I]Val5-ANG II in the kidney and adrenal glands of wild-type and Agtr1a−/− mice ( P < 0.01). Losartan largely blocked renal and adrenal uptake of [125I]Val5-ANG II in wild-type and Agtr1a−/− mice. Thus 80% of intracellular ANG II uptake in the kidney and adrenal glands is mediated by AT1areceptors, whereas AT1breceptor- and other non-receptor-mediated mechanisms account for 20% of the response. Our results suggest that AT1areceptor-mediated uptake of extracellular ANG II may play a physiological role in the kidney and adrenal glands.
Effects of resistance exercise with and without creatine supplementation on gene expression and cell signaling in human skeletal muscle
Authors: Deldicque Louise , Atherton Philip , Patel Rekha , Theisen Daniel , Nielens Henri , Rennie Michael J. , Francaux Marc
Published: November 2007

To test the hypothesis that creatine supplementation would enhance the anabolic responses of muscle cell signaling and gene expression to exercise, we studied nine subjects who received either creatine or a placebo (maltodextrin) for 5 days in a double-blind fashion before undergoing muscle biopsies: at rest, immediately after exercise (10 × 10 repetitions of one-leg extension at 80% 1 repetition maximum), and 24 and 72 h later (all in the morning after fasting overnight). Creatine supplementation decreased the phosphorylation state of protein kinase B (PKB) on Thr308 at rest by 60% ( P < 0.05) and that of eukaryotic initiation factor 4E-binding protein on Thr37/46 (4E-BP1) by 30% 24 h postexercise ( P < 0.05). Creatine increased mRNA for collagen 1 (α1), glucose transporter-4 (GLUT-4), and myosin heavy chain I at rest by 250%, 45%, and 80%, respectively, and myosin heavy chain IIA (MHCIIA) mRNA immediately after exercise by 70% (all P < 0.05). Immediately after exercise, and independent of creatine, mRNA for muscle atrophy F-box (MAFbx), MHCIIA, peroxisome proliferator-activated receptor γ coactivator-1α, and interleukin-6 were upregulated (60–350%; P < 0.05); the phosphorylation state of p38 both in the sarcoplasm and nucleus were increased (12- and 25-fold, respectively; both P < 0.05). Concurrently, the phosphorylation states of PKB (Thr308) and 4E-BP1 (Thr37/46) were decreased by 50% and 75%, respectively ( P < 0.05). Twenty-four hours postexercise, MAFbx, myostatin, and GLUT-4 mRNA expression decreased below preexercise values (−35 to −50%; P < 0.05); calpain 1 mRNA increased 70% 72 h postexercise ( P < 0.05) and at no other time. In conclusion, 5 days of creatine supplementation do not enhance anabolic signaling but increase the expression of certain targeted genes.
Anatomical and functional development of the pre-Bötzinger complex in prenatal rodents
Authors: Thoby-Brisson Muriel , Greer John J.
Published: November 2007

Developmental anomalies of central respiratory neural control contribute to newborn mortality and morbidity. Elucidation of the cellular, molecular, trophic, and genetic mechanisms involved in the formation and function of respiratory nuclei during prenatal development will provide a foundation for understanding pathologies. The pre-Bötzinger Complex (pre-BötC) is a specific group of neurons located in the ventrolateral medulla that is critical for respiratory rhythmogenesis. Thus it has become a major focus of research. Here, we provide an overview of current knowledge regarding the anatomical and functional emergence of the rodent pre-BötC during the prenatal period.
Measurement and Analysis of Postsynaptic Potentials Using a Novel Voltage-Deconvolution Method
Authors: Richardson Magnus J. E. , Silberberg Gilad
Published: November 2007

Accurate measurement of postsynaptic potential amplitudes is a central requirement for the quantification of synaptic strength, dynamics of short-term and long-term plasticity, and vesicle-release statistics. However, the intracellular voltage is a filtered version of the underlying synaptic signal and so a method of accounting for the distortion caused by overlapping postsynaptic potentials must be used. Here a voltage-deconvolution technique is demonstrated that defilters the entire voltage trace to reveal an underlying signal of well-separated synaptic events. These isolated events can be cropped out and reconvolved to yield a set of isolated postsynaptic potentials from which voltage amplitudes may be measured directly—greatly simplifying this common task. The method also has the significant advantage of providing a higher temporal resolution of the dynamics of the underlying synaptic signal. The versatility of the method is demonstrated by a variety of experimental examples, including excitatory and inhibitory connections to neurons with passive membranes and those with activated voltage-gated currents. The deconvolved current-clamp voltage has many features in common with voltage-clamp current measurements. These similarities are analyzed using cable theory and a multicompartment cell reconstruction, as well as direct comparison to voltage-clamp experiments.
Serotonergic Modulation of Afterhyperpolarization in a Neuron That Contributes to Learning in the Leech
Authors: Burrell Brian D. , Crisp Kevin M.
Published: November 2007

Modulation of afterhyperpolarization (AHP) represents an important mechanism by which excitability of a neuron can be regulated. In the leech brain, sensitization enhances excitability of the S-cell, an interneuron thought to play an important role in this form of nonassociative learning. This increase in excitability is serotonin (5-HT) dependent, but it is not known whether changes in AHP contribute to 5-HT–mediated enhancement of excitability. Therefore electrophysiological recordings and computational modeling were used to determine whether 5-HT enhances excitability via modulation of AHP. 5-HT reduced S-cell AHP and this decrease in the AHP corresponded with an increase in excitability. Little or no AHP is observed in the presence of Ca2+-free saline, suggesting the involvement of Ca2+-dependent K+channels. Furthermore, AHP amplitude decreased following treatment with drugs (tubocurare and charybdotoxin) that block Ca2+-dependent K+channel activity. The S-cell also exhibits an afterdepolarization (ADP), which is usually masked by the AHP, and was inhibited by the Na+channel blocker saxitoxin. A model of the S-cell AHP was constructed using two Ca2+-dependent K+currents and a Na+-driven ADP current. Reduction of the model conductances underlying the AHP to mimic the effects of 5-HT was sufficient to enhance excitability. These findings were confirmed in occlusion experiments in which pretreatment with tubocurare was able to block 5-HT–mediated decreases in mAHP levels and increases in excitability. These data show that modulation of S-cell AHP can contribute to 5-HT–mediated increases in excitability and that the S-cell afterpotential is due to the combined effects of AHP- and ADP-producing currents.
Dendritic Properties of Turtle Pyramidal Neurons
Authors: Larkum Matthew E. , Watanabe Shigeo , Lasser-Ross Nechama , Rhodes Paul , Ross William N.
Published: November 2007

The six-layered mammalian neocortex evolved from the three-layered paleocortex, which is retained in present-day reptiles such as the turtle. Thus the turtle offers an opportunity to examine which cellular and circuit properties are fundamental to cortical function. We characterized the dendritic properties of pyramidal neurons in different cortical regions of mature turtles, Pseudemys scripta elegans, using whole cell recordings and calcium imaging from the axon, soma, and dendrites in a slice preparation. The firing properties, in response to intrasomatic depolarization, resembled those previously recorded with sharp electrodes in this preparation. Somatic spikes led to active backpropagating high-amplitude dendritic action potentials and intracellular calcium ion concentration ([Ca2+]i) changes at all dendritic locations, suggesting that both backpropagation and dendritic voltage-gated Ca2+ channels are primitive traits. We found no indication that Ca2+ spikes could be evoked in the dendrites, but fast Na+ spikes could be initiated there following intradendritic stimulation. Several lines of evidence indicate that fast, smaller-amplitude somatic spikes (“prepotentials”) that are easily recorded in this preparation are generated in the axon. Most synaptically activated [Ca2+]i changes resulted from Ca2+ entry through voltage-gated channels. In some cells synaptic stimulation evoked a delayed Ca2+ wave due to release from internal stores following activation of metabotropic glutamate receptors. With some small differences these properties resemble those of pyramidal neurons in mammalian species. We conclude that spike backpropagation, dendritic Ca2+ channels, and synaptically activated Ca2+ release are primitive and conserved features of cortical pyramidal cells, and therefore likely fundamental to cortical function.