bluuebunny/crossref_metadata_2025 huggingface dataset:
Keeping the Company fit
Authors: Whiteman Maria
Published: May 2006

Notes that corporate fitness has emerged as an extension of health
provision. Argues that in‐house fitness facilities are not an expensive
extra but that the benefits of a corporate fitness programme are an
asset to recruitment and retention. Discusses how to find physical space
for a fitness facility and concludes with a brief corporate fitness
guide.
How to run better business meetings
Authors: Johnson Virginia
Published: May 2006

Suggests eight steps to run a better business meeting. Includes
agendas, presentation aids, environment, timing and control. Concludes
that well run meetings are powerful communication tools and earn
recognition from colleagues and superiors.
Executive Development at Tenneco: Interview with Ken Otto
Authors: Heisler William
Published: May 2006

Describes Tenneco as dealing primarily in manufacturing but with
major interests in energy. Addresses issues of executive development
including quality and availability of management, appointment strategies
for key management and their system for succession planning. Discusses
the Executive Resource Planning Program and the use of the Executive
Incentive Compensation Program to reward those who are meeting the
strategic development objectives. Concludes that their program helps
them to grow potential CEOs within the organisation.
Counselling in management: Just another name for an
old‐fashioned rose?
Authors: Sidney Elizabeth
Published: May 2006

Discusses counselling in management with reference to appraisal and
stress factors. Defines modern stress points including new technology,
privatisation and relocation. Calls for counselling to be legitimised in
management as a necessary part of the task.
Sex differences in pectoral muscles but not in pectoral fins in the three‐spined stickleback Gasterosteus aculeatus
Authors: Hoffmann E. , Borg B.
Published: May 2006

The pectoral muscle index (IPM)(IPM = 100 MPM M−1, where MPM and M are the pectoral muscle and body masses, respectively) fin‐area and fin ray length were studied over a year in male and female three‐spined stickleback Gasterosteus aculeatus from a marine population (Öresund, Sweden) kept under simulated natural light and temperature conditions. A castration‐replacement experiment was used to test androgen effects on the IPM, fin‐area and fin ray length. Non‐breeding males were castrated or sham‐operated in winter (i.e. the fish had low levels of androgens). Castrated control and sham‐operated fish were implanted with empty Silastic capsules and castrated groups with capsules containing the androgens testosterone or 11‐ketoandrostenedione into the abdominal cavity. The experiment was terminated after 41 days, when the controls had matured. No morphological differences were found in pectoral fins between sexes during the year, except during the peak breeding season (May), where females showed larger fin‐area and longer fin ray in length compared to males. No effects of androgens treatment or of castration on pectoral fin‐area or fin ray length was observed. Breeding and non‐breeding males showed higher IPM compared to females. The lower IPM in females than in males could not be explained by the larger gonads in the former alone, as a sex difference in IPM was still present after deduction of the ovaries from the female body mass. The IPM was higher in sham‐operated compared to castrated fish. No effects of androgens treatment on IPM was observed.
Fish habitat associations in a spatially variable desert stream
Authors: Rogowski D. L. , Reiser H. , Stockwell C. A.
Published: May 2006

White sands pupfish Cyprinodon tularosa were sampled with minnow traps along the length of Lost River, a highly variable desert stream in New Mexico, to evaluate if their abundance, median standard length (LS) and sex ratio values differed by microhabitat variables. Habitat measurements were made in a 4 m2 area around the minnow trap. White Sands pupfish populations were primarily structured by LS. As specific conductance and surface area increased, median size of fish decreased. Shallow areas with higher specific conductance were correlated with an increased number of fish.
Early growth and juvenile population structure of lemon sharks Negaprion brevirostris in the Atol das Rocas Biological Reserve, off north‐east Brazil
Authors: Freitas R. H. A. , Rosa R. S. , Gruber S. H. , Wetherbee B. M.
Published: May 2006

Lemon sharks Negaprion brevirostris were sampled in the Atol das Rocas, a nursery area, on nine occasions from March 1999 to October 2003, during which 157 individuals were tagged and 35 were recaptured. The male : female sex ratio of captured individuals was 1 : 1·12. Mean ± s.d. growth rates were 24·7 ± 3·4 cm year−1 in total length (LT), 20·7 ± 3·2 cm year−1 in fork length, and 19·5 ± 2·7 cm year−1 in precaudal length. There was no significant difference in growth rates between males and females. Mean ± s.d. increase in mass was 2565 ± 762 g year−1. The von Bertalanffy growth parameters estimated by the Fabens method based on LT were: k = 0·077, L∞ = 399·9 cm and t0 = −2·16. Despite the large variation of environmental conditions, particularly of tidal range and currents, and the lack of protective mangrove cover in the nursery area at Atol das Rocas, juvenile lemon sharks grew relatively faster than at other nurseries. Such rapid growth could be a response to abundant food availability or high risk of predation by adults that enter the nursery area.
Larval Konosirus punctatus(Clupeidae) in a brackish river mouth on the Pacific coast of central Japan
Authors: Kawasaki M. , Watanabe Y. , Shirafuji N. , Chimura M. , Moku M. , Funaki O. , Saruwatari T. , Kawamura T.
Published: May 2006

Eggs of Konosirus punctatus in early developmental stages were collected from the eastern part of the mouth of Sagami Bay on the Pacific coast of central Japan. Advanced‐stage eggs and early larvae with notochord length (LN) of <7·5 mm were collected from the inner bay near the mouth of the Sagami River. Feeding larvae of >8·4 mm LN were distributed in the mouth of the river, and juveniles of 24–90 mm standard length (LS) were collected from the lower reaches of the river between the river mouth and c. 3 km upstream of the river mouth. Hatch dates of larvae and juveniles collected in 2001 (n = 158) and in 2002 (n = 109) extended from late March to late July. The relationship between the otolith radius (RO) and LN or LS changed during the metamorphosis stage as characterized by 320 μm RO and 22 mm LS. Otolith growth rate, as an index of somatic growth rates in larval and early juvenile stages, was higher in cohorts that hatched later in the spawning season, i.e. from March to July. Konosirus punctatus that were spawned in the bay mouth area survived with different growth histories in the bay and lower reaches of the river, and recruited to the young‐of‐year population in the Pacific coastal waters of central Japan.
A comparison of written materials vs. materials and counselling for women with sexual dysfunction and multiple sclerosis
Authors: Christopherson Jeannine Marguerite , Moore Katherine , Foley Frederick W , Warren Kenneth G
Published: May 2006

Aim.  Evaluate whether symptoms of vaginal dryness, low libido, less intense or delayed orgasm could be improved in women with multiple sclerosis who took part in an education or education plus counselling programme.

Background.  Sexual dysfunction, a prevalent symptom in women with multiple sclerosis, can negatively affect quality‐of‐life.

Methods.  Women attending a large multiple sclerosis clinic were invited and 62 were randomized into one of two groups. Group 1 received written materials on primary, secondary and tertiary sexual dysfunction in multiple sclerosis as well as additional resources (books, websites, list of local psychologists specializing in sexual counselling). Group 2 received the same written materials as well as three counselling sessions from the clinic nurse, the latter two by telephone. The primary outcome measures were the expanded disability status scale and the multiple sclerosis intimacy and sexuality questionnaire‐19. Repeated‐measures analysis of variance was used to evaluate sexual dysfunction score over time and to compare two groups.

Results.  At baseline, total expanded disability status scale scores were not correlated with primary, secondary or tertiary sexual dysfunction. Total multiple sclerosis intimacy and sexuality questionnaire‐19 score was correlated with use of anti‐cholinergic medications [r (54) = 0·28, P < 0·05], but no other medications, alcohol or tobacco use. Both groups had equivalent and significant reductions in primary sexual dysfunction [F (1) = 14·79, P < 0·001] postintervention. There was a trend towards an interaction effect for tertiary sexual dysfunction [F (1) = 2·88, P = 0·096], in the direction of group 2 (education and counselling). Subjectively, women welcomed the opportunity to discuss sexual concerns and noted that the written information allowed a framework for initiating discussion with their spouses.

Conclusion.  Relatively straightforward interventions provided by a clinic nurse may help women cope with the symptoms of sexual dysfunction associated with multiple sclerosis. Women who do not benefit from basic interventions could then be referred to an expert sexual dysfunction practitioner.

Relevance to clinical practice.  Women with multiple sclerosis experience many disease‐related physical and emotional challenges of which sexuality is only one. Sensitivity to sexual dysfunction and being willing to approach the topic is appreciated by women with multiple sclerosis. Nurses do not require in‐depth expertise to offer some basic suggestions which may significantly improve life quality and assist the woman with multiple sclerosis to talk about or cope with sexuality issues.
The functional repertoire of prokaryote cellulosomes includes the serpin superfamily of serine proteinase inhibitors
Authors: Kang Seungha , Barak Yoav , Lamed Raphael , Bayer Edward A. , Morrison Mark
Published: May 2006

Many of the Firmicutes bacteria responsible for plant polysaccharide degradation in Nature produce a multiprotein complex called a cellulosome, which co‐ordinates glycoside hydrolase assembly, bacterial adhesion to substrate and polysaccharide hydrolysis. Cellulosomal proteins possess a dockerin module, which mediates their attachment to the scaffoldin protein via its interaction with cohesin modules, and only glycoside hydrolases and other carbohydrate active enzymes were known to reside within the cellulosome. We show here with Clostridium thermocellum ATCC 27405 that members of the serpin superfamily of serine proteinase inhibitors, which are best recognized for their conformational flexibility and co‐ordination of key regulatory functions in multicellular eukaryotes, also reside within the cellulosome. These studies are the first to expand the cellulosome paradigm of protein complex assembly beyond glycoside hydrolase and carbohydrate active enzymes, and to include a newly identified functionality in the Firmicutes.
Identification of a response regulator gene for catabolite control from a PCB‐degrading β‐proteobacteria, Acidovorax sp. KKS102
Authors: Ohtsubo Yoshiyuki , Goto Hiroyuki , Nagata Yuji , Kudo Toshiaki , Tsuda Masataka
Published: May 2006

Acidovorax sp. (formally Pseudomonas sp.) strain KKS102 carries a bph operon for the degradation of PCB/biphenyl. Transcription from the pE promoter for the bph operon was found to be under catabolite control, i.e. the promoter activity was at a lower level when succinate, fumarate or acetate was added to the culture. Some mutations in the immediate upstream region of the pE promoter resulted in catabolite‐insensitive and constitutively low promoter activity, suggesting that a transcriptional activator was involved in catabolite control. A genetic screen for a pE promoter activator identified two tandemly arranged genes, bphP and bphQ, that encoded proteins homologous to the sensor kinases and response regulators, respectively, of two‐component regulatory system. In the bphPQ double mutant, pE promoter activity was weak and catabolite‐insensitive, and a supply of the bphQ gene alone led to the restoration of the catabolite response. The mechanism of catabolite repression in KKS102 is explained in terms of inhibition of activation by BphQ. The genes highly similar to bphQ were found from several β‐proteobacteria, such as Burkholderia cenocepacia J2315, B. multivorans ATCC17616, B. xenovorans LB400 and Ralstonia solanacearum RS1085.
Paradoxical effects of NPY in the suprachiasmatic nucleus
Authors: Gamble Karen L. , Paul Ketema N. , Karom Mary C. , Tosini Gianluca , Albers H. Elliott
Published: May 2006

The circadian clock in the suprachiasmatic nucleus (SCN) is synchronized by the 24 h, light : dark cycle, and is reset by photic and non‐photic cues. The acute effects of light in the SCN include the increase of mRNA levels of the circadian clock gene Per1 and a dramatic reduction of pineal melatonin. Neuropeptide Y (NPY), which appears to mediate the phase‐resetting effects of non‐photic stimuli, prevents the ability of light, and stimuli that mimic light, to phase shift the circadian clock when injected into the SCN. The purpose of the present study was to determine if NPY inhibits the ability of light to suppress pineal melatonin. Surprisingly, NPY injected into the SCN of hamsters mimicked the effects of light by suppressing pineal melatonin levels. To confirm that NPY inhibited the effects of light on the induction of Per1 mRNA levels, Per1 mRNA levels in the SCN were measured in these same animals. NPY significantly reduced Per1 mRNA levels induced by the light pulse. The suppression of melatonin by NPY appears to be mediated by the same subtype of NPY receptors in the SCN that mediate the modulation of phase shifts. Injection of Y5 receptor agonists mimicked the effects of NPY on pineal melatonin, while injection of a Y2 agonist did not. Thus, these data are the first to demonstrate the paradoxical effects of NPY within the SCN. NPY mimics the effects of light on pineal melatonin and inhibits the effects of light on the induction of Per1 mRNA.
The impact of the overactive bladder on health‐related utility and quality of life
Authors: CURRIE CRAIG J. , MCEWAN PHIL , POOLE CHRIS D. , ODEYEMI ISAAC A.O. , DATTA SHIBENDRA N. , MORGAN CHRISTOPHER L.
Published: May 2006

OBJECTIVE

To evaluate the impact of the overactive bladder (OAB) on quality of life and health‐related utility.

PATIENTS AND METHODS

In a study conducted in Cardiff and Vale NHS Trust, patients were identified from an academic urology unit inpatient database for admissions and sent a postal survey. The survey pack comprised questionnaires on demography, urological functioning, health utility (EQ5Dindex), and health‐related quality of life (Short Form‐36, SF36). Respondents were classified according to general urinary status, frequency, urgency, and stress incontinence.

RESULTS

Of 2193 surveys dispatched, 609 (27.8%) were returned; of these patients, 52% had incontinence, of whom 83% had both frequency and urgency, and 60% stress incontinence. Patients with stress incontinence reported a mean (sd) EQ5Dindex of 0.578 (0.331), compared to 0.714 (0.281) for all other patients (P < 0.001). From the SF36, respondents scored lowest in the role physical domain and highest in the mental domain, with mean scores of 33.8 and 72.1, respectively. Multivariate analysis of SF36 and EQ5Dindex scores, controlling for age, gender and body mass index, showed that incontinence was associated with a notable reduction in the EQ5Dindex and SF36 scores across all domains.

CONCLUSION

This study showed a significant reduction in quality of life for all patient groups with OAB; in particular, stress incontinence had the greatest impact.
Testosterone levels in men with erectile dysfunction
Authors: MARTÍNEZ‐JABALOYAS JOSÉ M. , QUEIPO‐ZARAGOZÁ ALFONSO , PASTOR‐HERNÁNDEZ FRANCISCO , GIL‐SALOM MANUEL , CHUAN‐NUEZ PASCUAL
Published: May 2006

OBJECTIVE

To investigate the frequency of hypogonadism in men with erectile dysfunction (ED) and to assess which factors are related with low testosterone levels.

PATIENTS AND METHODS

In all, 165 men with ED were assessed; the evaluation included: hormonal profiles, serum total and free testosterone (using Vermeulen’s formula) levels, and self‐reported questionnaires on erectile function and desire domains of the International Index of Erectile Function. The frequency of hypogonadism was established using total and free testosterone levels as diagnostic criteria. The factors that might influence testosterone levels were evaluated by univariate and multivariate statistical analysis, and a logistic regression was used to determine which factors can predict free testosterone levels below normal limits (biochemical hypogonadism).

RESULTS

Using the total testosterone levels, 4.8% of the men were hypogonadal, whereas when using the free testosterone levels, 17.6% were hypogonadal. In the univariate analyses, not smoking and hypertension were associated with lower total and free testosterone levels. Ageing, absence of nocturnal erections and a lower erectile function score were only associated with lower free testosterone serum levels. There was no association between total and free testosterone levels and desire. In the multivariate analysis, only total testosterone levels were related to hypertension, while free testosterone levels were related to age and nocturnal erections. For biochemical hypogonadism, simple logistic regression analysis selected age, erectile function score and aetiological diagnosis of ED as predictors. In the multivariate analysis only the erectile function score had significant independent prognostic value.

CONCLUSIONS

The frequency of hypogonadism is higher when free testosterone levels are used for diagnosis. The total and free testosterone levels were not related to the level of sexual desire in men with ED. The free testosterone levels could be related to the quality and frequency of nocturnal erections, and when ED is more severe, it is more probable that free testosterone levels are below the ‘normal’ limit.
Fine‐needle aspiration cytology predicts inguinal lymph node metastasis without antibiotic pretreatment in penile carcinoma
Authors: SAISORN ISARES , LAWRENTSCHUK NATHAN , LEEWANSANGTONG SUNAI , BOLTON DAMIEN M.
Published: May 2006

OBJECTIVE

To evaluate the accuracy of fine‐needle aspiration (FNA) cytology of palpable inguinal lymphadenopathy before definitive management of the primary tumour, in predicting inguinal lymph node (LN) metastasis in men with primary squamous cell carcinoma (SCC) of the penis.

PATIENTS AND METHODS

Sixteen men with primary SCC of the penis and palpable inguinal lymphadenopathy (unilateral or bilateral) were treated by primary resection and bilateral inguinal LN dissection. FNA cytology was analysed for 25 palpable inguinal LNs at the time of penile biopsy. The sensitivity, specificity and accuracy of FNA cytology was compared with the histological findings from surgical LN clearance.

RESULTS

The 25 FNAs were without complication and without evidence of implantation of metastasis in the needle tracts; 14 FNA samples were positive for metastasis, 10 were negative, and one was inconclusive. From the histological assessment of the surgical inguinal LN specimens, FNA cytology had a sensitivity of 93%, and specificity of 91% in predicting metastatic disease.

CONCLUSION

FNA cytology of palpable inguinal lymphadenopathy before surgery for the primary tumour has a high sensitivity and specificity for metastatic penile cancer. This procedure permits early inguinal lymphadenectomy where appropriate without need for prolonged initial antibiotic treatment.
The Judge as ‘Political Advisor’: Behind the Scenes at the National Industrial Relations Court
Authors: Spencer Maureen , Spencer John
Published: May 2006

The recent opening under the 30‐year rule of official papers concerning the Industrial Relations Act 1971 makes it possible to reappraise the conventional view of this short‐lived statute and also more general implications of the process of policy making at a time of acute political crisis. The papers shed new light on the relationship between the government and the judiciary, in particular the President of the National Industrial Relations Court, Sir John Donaldson. They provide empirical evidence of how the judicial and political arms of government dealt with social and industrial upheavals and they prompt reflections on the nature of the separation of powers in the United Kingdom's constitutional arrangements. It is argued that, in examining the nature and extent of judicial independence, constitutional law scholars have hitherto concentrated on executive influence on the judiciary and tended to ignore the extent to which judges may secretly influence politicians.
Gameplaying for maths learning: cooperative or not?
Authors: Ke Fengfeng , Grabowski Barbara
Published: May 2006

This study investigated the effects of gameplaying on fifth‐graders’ maths performance and attitudes. One hundred twenty five fifth graders were recruited and assigned to a cooperative Teams‐Games‐Tournament (TGT), interpersonal competitive or no gameplaying condition. A state standards‐based maths exam and an inventory on attitudes towards maths were used for the pretest and posttest. The students’ gender, socio‐economic status and prior maths ability were examined as the moderating variables and covariate. Multivariate analysis of covariance (MANCOVA) indicated that gameplaying was more effective than drills in promoting maths performance, and cooperative gameplaying was most effective for promoting positive maths attitudes regardless of students’ individual differences.
Crowd‐In: The Effect of Private Health Insurance Markets on the Demand for Medicaid
Authors: Perreira Krista M.
Published: May 2006

Objective. To investigate the effects of local labor market conditions and the availability of employer‐sponsored health insurance on exits from the Medicaid program.

Data Source. Data for this project come from a unique administrative database containing a 2 percent sample of all cases on California's Medicaid program in 1987 and a 2 percent sample of all new cases starting each year between 1987 and 1995.

Study Design. The results are estimated using a discrete duration model where the monthly exit probability is a function of demographic characteristics, local labor market variables, the probability of having employer‐sponsored insurance, and fixed year and county effects.

Principal Findings. Improvements in labor market opportunities (i.e., employment growth, wage growth, and increases in the availability of employer‐sponsored health insurance) promote exits off the Medicaid program. A 2.5 percentage point increase in the availability of employer‐sponsored insurance leads to a 6 percent increase in the probability that a completed spell lasts no more than 2 years. It would take a 2 percentage point decrease in unemployment rates or a 10 percent increase in average quarterly earnings to yield an equivalent increase in the likelihood of exiting Medicaid within 2 years. These effects are robust to the inclusion of county‐level fixed effects and time effects.

Conclusions. Medicaid expenditures and caseloads are sensitive to local economic fluctuations and secular trends in the availability of health insurance. Continued decreases in employer‐based health insurance coverage will greatly increase the demand for public insurance coverage and the financial pressures on state governments.
Stochastic, Compartmental, and Dynamic Modeling of Cross‐Contamination During Mechanical Smearing of Cheeses
Authors: Aziza Fanny , Mettler Eric , Daudin Jean‐Jacques , Sanaa Moez
Published: May 2006

Cheese smearing is a complex process and the potential for cross‐contamination with pathogenic or undesirable microorganisms is critical. During ripening, cheeses are salted and washed with brine to develop flavor and remove molds that could develop on the surfaces. Considering the potential for cross‐contamination of this process in quantitative risk assessments could contribute to a better understanding of this phenomenon and, eventually, improve its control. The purpose of this article is to model the cross‐contamination of smear‐ripened cheeses due to the smearing operation under industrial conditions. A compartmental, dynamic, and stochastic model is proposed for mechanical brush smearing. This model has been developed to describe the exchange of microorganisms between compartments. Based on the analytical solution of the model equations and on experimental data collected with an industrial smearing machine, we assessed the values of the transfer parameters of the model. Monte Carlo simulations, using the distributions of transfer parameters, provide the final number of contaminated products in a batch and their final level of contamination for a given scenario taking into account the initial number of contaminated cheeses of the batch and their contaminant load. Based on analytical results, the model provides indicators for smearing efficiency and propensity of the process for cross‐contamination. Unlike traditional approaches in mechanistic models, our approach captures the variability and uncertainty inherent in the process and the experimental data. More generally, this model could represent a generic base to use in modeling similar processes prone to cross‐contamination.
Understanding the Risk of an Avian Flu Pandemic: Rational Waiting or Precautionary Failure?
Authors: Basili Marcello , Franzini Maurizio
Published: May 2006

The precautionary principle (PP) has been proposed as the proper guide for the decision‐making criteria to be adopted in the face of the new catastrophic risks that have arisen in the last decades. This article puts forward a workable definition of the PP based on the so‐called α‐maximin expected utility approach, applying it to the possible outbreak of the avian flu disease among humans. Moreover, it shows how the shortage and/or lack of effective drugs against the infection of the virus A(H5N1) among humans can be considered a precautionary failure.
Product Cost Estimation: Technique Classification and Methodology Review
Authors: Niazi Adnan , Dai Jian S. , Balabani Stavroula , Seneviratne Lakmal
Published: May 2006

This paper provides a detailed review of the state of the art in product cost estimation covering various techniques and methodologies developed over the years. The overall work is categorized into qualitative and quantitative techniques. The qualitative techniques are further subdivided into intuitive and analogical techniques, and the quantitative ones into parametric and analytical techniques. Each of the techniques is then described and discussed, in detail, with further subdivisions. The paper also signifies the importance of cost estimation in the early phases of the design cycle and, as such, briefly discusses the current trends and future directions in the area. Research work carried out in the field with reference to specific applications is also reviewed. The paper provides a comprehensive literature review in the field and should be useful to researchers and practitioners interested in this field.
The Investigation of Gravity-Driven Metal Powder Flow in Coaxial Nozzle for Laser-Aided Direct Metal Deposition Process
Authors: Pan Heng , Sparks Todd , Thakar Yogesh D. , Liou Frank
Published: May 2006

The quality and efficiency of laser-aided direct metal deposition largely depends on the powder stream structure below the nozzle. Numerical modeling of the powder concentration distribution is complex due to the complex phenomena involved in the two-phase turbulence flow. In this paper, the gravity-driven powder flow is studied along with powder properties, nozzle geometries, and shielding gas settings. A 3-D numerical model is introduced to quantitatively predict the powder stream concentration variation in order to facilitate coaxial nozzle design optimizations. Effects of outer shielding gas directions, inner/outer shielding gas flow rate, powder passage directions, and opening width on the structure of the powder stream are systematically studied. An experimental setup is designed to quantitatively measure the particle concentration directly for this process. The numerical simulation results are compared with the experimental data using prototyped coaxial nozzles. The results are found to match and then validate the simulation. This study shows that the particle concentration mode is influenced significantly by nozzle geometries and gas settings.
Low noise signal-to-noise ratio enhancing readout circuit for current-mediated active pixel sensors
Authors: Ottaviani Tony , Karim Karim S. , Nathan Arokia , Rowlands John A.
Published: May 2006

Diagnostic digital fluoroscopic applications continuously expose patients to low doses of x-ray radiation, posing a challenge to both the digital imaging pixel and readout electronics when amplifying small signal x-ray inputs. Traditional switch-based amorphous silicon imaging solutions, for instance, have produced poor signal-to-noise ratios (SNRs) at low exposure levels owing to noise sources from the pixel readout circuitry. Current-mediated amorphous silicon pixels are an improvement over conventional pixel amplifiers with an enhanced SNR across the same low-exposure range, but whose output also becomes nonlinear with increasing dosage. A low-noise SNR enhancing readout circuit has been developed that enhances the charge gain of the current-mediated active pixel sensor (C-APS). The solution takes advantage of the current-mediated approach, primarily integrating the signal input at the desired frequency necessary for large-area imaging, while adding minimal noise to the signal readout. Experimental data indicates that the readout circuit can detect pixel outputs over a large bandwidth suitable for real-time digital diagnostic x-ray fluoroscopy. Results from hardware testing indicate that the minimum achievable C-APS output current that can be discerned at the digital fluoroscopic output from the enhanced SNR readout circuit is 0.341nA. The results serve to highlight the applicability of amorphous silicon current-mediated pixel amplifiers for large-area flat panel x-ray imagers.
Photoluminescence in the silicon-oxygen system
Authors: Meldrum A. , Hryciw A. , MacDonald A. N. , Blois C. , Marsh K. , Wang J. , Li Quan
Published: May 2006

The luminescent properties of SiOx ranging in composition between x=0 and x=2 are presented. Luminescence in the SiOx system is found to be tunable across the full visible spectrum and into the near infrared. The data are used to generate an emission color map for the complete SiOx system. At the lower annealing temperatures, several lines of evidence suggest that the luminescence is due to the presence of amorphous silicon nanoclusters, whereas for higher annealing temperatures the emission is dominated by silicon nanocrystals.
Rapid thermal annealing of InAs∕GaAs quantum dots with a low-temperature-grown InGaP cap layer
Authors: Jiang W. H. , Thompson D. A. , Hul’ko O. , Robinson B. J. , Mascher P.
Published: May 2006

A single layer of self-assembled InAs quantum dots was grown on a GaAs (001) substrate by gas source molecular-beam epitaxy. The quantum dots were overgrown with 65nm GaAs, 25nm InGaP, and a 10nm GaAs etch-stop layer. This was either uncapped or capped with 100nm of low-temperature (LT)-grown, lattice-matched InGaP (LT-InGaP) or with a SiO2 layer or Al2O3 layer. Photoluminescence (PL) measurements were made on samples before and after rapid thermal annealing at 550–900°C and for 15–120s at 650°C. Samples capped with LT-InGaP showed a significant blueshift of the PL peak wavelength for anneals above 575°C. By comparison, for the SiO2-capped and uncapped samples, the net blueshift only becomes significant for anneals >700°C, while an Al2O3 cap actually reduces the blueshift and suppresses the intermixing. It appears that the best conditions for spatially controlling the quantum dot intermixing occur with annealing at low temperatures (600–650°C).
Temperature characterization of a-Si:H thin-film transistor for analog circuit design using analog hardware description language modeling
Authors: Ng Clement , Nathan Arokia
Published: May 2006

A characterization of the a-Si:H thin-film transistor (TFT) under varying ambient temperature is essential to the successful design of any circuit that uses a-Si:H TFTs as analog devices. In this study, a multitude of a-Si:H TFTs under different manufacturing processes as well as varying sizes are subjected to temperatures ranging from −40 to 100°C while their transfer characteristics are being measured. The collected data are used to extract the various parameters that govern the TFT’s characteristics such as power parameter (α), threshold voltage (Vt), and effective mobility (μeff). The parameters are analyzed to retrieve their dependence on ambient temperature, which is subsequently incorporated in VERILOG-A to expedite circuit designs and analysis under diverse temperature environments.
Signal and noise modeling and analysis of complementary metal-oxide semiconductor active pixel sensors
Authors: Faramarzpour Naser , Jamal Deen M. , Shirani Shahram
Published: May 2006

The active pixel sensor (APS) structure is the most common pixel element for photodetection systems in standard complementary metal-oxide semiconductor technology. The focus of our work is on finding functional characteristics for low-light level design. Shot, reset, thermal, and 1∕f noise sources are considered in APS noise modeling. We also consider a higher-order empirical model for the p-n junction capacitance to accurately calculate the signal value. Signal-to-noise ratio curves are then determined for various values of integration time, signal level, and other design parameters. These curves can lead to the optimum operating point of the APS element.
Single photon counter for digital x-ray mammography tomosynthesis
Authors: Goldan Amir H. , Karim Karim S. , Rowlands John A.
Published: May 2006

Photon counting is an emerging detection technique that is promising for mammography tomosynthesis imagers. In photon counting systems, the value of each image pixel is equal to the number of photons that interact with the detector. In this research, we introduce the design and implementation of a low noise, photon counting pixel for digital mammography tomosynthesis in 0.18μm crystalline silicon complementary metal-oxide semiconductor technology. The design comprises of a low noise, charge-integrating amplifier, a low offset voltage comparator, a decision-making unit, a mode selector, and a pseudorandom counter. Theoretical calculations and simulation results of linearity, gain, and noise of the photon counting pixel are presented.
Inductively coupled plasma etching of Si1−xGex in CF4∕Ar and Cl2∕Ar discharges
Authors: Wu San Lein , Lee Chun Hsin , Chang Shoou Jinn , Lin Yu Min
Published: May 2006

In this article, we report the experimental realization of SiGe∕Si materials using CF4∕Ar and Cl2∕Ar mixed-gas inductively coupled plasma (ICP) etching process. The effects of process parameters such as gas combination and gas species on etch rates and selectivities were investigated. It was found that samples in CF4 gas result in a faster etching rate than those obtained in Cl2 gas, which are responsible for a lower boiling point for Si-based fluoride. The lower boiling point provides more chemically active Si and SiGe materials. Moreover, the selectivity of 1.5 between Si0.3Ge0.7∕Si by ICP technology was found and higher than that obtained previously by reactive ion etching reported in the literature. Based on these etch characteristics, the application of the ICP process to the device fabrication of SiGe doped-channel field-effect transistors was conducted. The devices using ICP mesa have excellent pinch-off characteristics with relatively low leakage current, small output conduction in the saturated region, and low knee voltage.
Molecular model T6:C60 bulk-heterojunction solar cells
Authors: Alem S. , Pandey A. K. , Unni K. N. N. , Nunzi J.-M. , Blanchard P.
Published: May 2006

Organic photovoltaic devices offer a large technological potential as a renewable source of electrical energy because of their low cost and ease of processing. For the last few years, the interest in such devices has grown rapidly, allowing multiplication of the solar conversion efficiency by 5 within about 10years. The highest conversion efficiency obtained is now close to 5% with a spin-coated polythiophene-fullerene blend. For a better understanding of those polymer blend systems, we have fabricated a coevaporated solar cell from model molecules. The molecular blend was composed of sexithiophene (α,α′-dihexylsexithiophene, T6) as a donor and fullerene C60 as an acceptor. The influence of the T6:C60 proportion was studied for an active layer of 100nm thickness. The conversion efficiency obtained with the optimal proportion of T6:C60 (40–60) is 0.7%. Reverse bias annealing effect was studied by measuring the current-voltage characteristics after each postprocessing step. The conversion efficiency reached 1% but still remained much less than for the polymer bulk heterojunction. This major difference may come from the spontaneous phase separation which takes place in polymers to form an interpenetrated network.
Electron inelastic mean free path and dielectric properties of a-boron, a-carbon, and their nitrides as determined by quantitative analysis of reflection electron energy loss spectroscopy
Authors: Prieto P. , Quirós C. , Elizalde E. , Sanz J. M.
Published: May 2006

The quantitative analysis of reflection electron energy loss spectroscopy (REELS) spectra of amorphous boron (a-B), amorphous carbon (a-C), and their respective nitrides (i.e., BNx and CNx) has been performed to obtain the energy loss function (ELF) and the electron inelastic mean free path (IMFP) of the respective materials. In the case of boron we have studied different thin films over a wide range of stoichiometries, i.e., B, BN0.4, BN0.6, BN0.8, BN0.9, and commercially available hexagonal boron nitride (h-BN). In the case of carbon films we have analyzed a-C, CN0.3, and CN0.5 since the nitrogen content could not be increased above CN0.5. The analysis of the respective REELS spectra has been performed according to the model developed by Yubero and Tougaard [Phys. Rev. B 46, 2486 (1992)] and Yubero et al. [Phys. Rev. B 52, 9719 (1996)]. In addition we have included the study of the influence of some of the input parameters (refraction index, density, gap energy, and momentum dispersion coefficient) required by the model, which, rather commonly, are not well known and are dependent on the composition. The ELFs determined in this study are compared with published data when available. The IMFPs are compared with values predicted by the TPP-2M formulas and values reported for similar compounds.
Thermochromic vanadium dioxide smart coatings grown on Kapton substrates by reactive pulsed laser deposition
Authors: Soltani M. , Chaker M. , Haddad E. , Kruzelesky R. V.
Published: May 2006

Thermochromic undoped and metal (Ti and W)-doped VO2 smart coatings were achieved on Kapton HN by reactive pulsed laser deposition. The optimization of the deposition was conducted with Si (100) substrates. The coatings were deposited at relatively low deposition temperatures (250, 300, and 350°C), which are compatible with the characteristics of Kapton. The stoichiometry of the VO2-coated Kapton was confirmed by x-ray photoelectron spectroscopy analysis of the vanadium and oxygen bands. Moreover, the single phase VO2 was confirmed by x-ray diffraction of VO2∕Si synthesized at 300°C. Unlike VO2/Kapton, the VO2∕Si exhibited the well-known semiconductor-to-metallic transition, as shown by the temperature dependence of the infrared transmittance. This coating exhibited a similar transition temperature to that of VO2 single crystal (≈68°C), but a small transmittance switching (about 7%) at 2.5μm. The temperature dependence of the electrical resistivity of all coatings on Kapton was investigated by means of the standard four-point probe technique. The resistivity decreased with increasing temperature. No abrupt semiconductor-to-metallic transition was observed either for undoped or for metal-doped VO2 coatings. It was found that Ti and W dopants have an antagonistic effect on the resistivity. The resistivity was enhanced by the Ti dopant, whereas it was decreased for W-doped VO2 coatings. These results show that the tunability of the resistivity can be tailored either by controlling the deposition temperature or by adjusting the concentration of Ti and W dopants. In addition, at room temperature a much higher temperature coefficient of resistance of −3.29%∕°C was achieved in W(0.5%)-doped VO2/Kapton. Finally, these VO2 smart coatings are promising materials for the IR sensing and sunshield applications.
Low-temperature sputtering of crystalline TiO2 films
Authors: Musil J. , Heřman D. , Šícha J.
Published: May 2006

This article reports on the investigation of reactive magnetron sputtering of transparent, crystalline titanium dioxide films. The aim of this investigation is to determine a minimum substrate surface temperature Tsurf necessary to form crystalline TiO2 films with anatase structure. Films were prepared by dc pulsed reactive magnetron sputtering using a dual magnetron operating in bipolar mode and equipped with Ti(99.5) and ceramic Ti5O9 targets. The films were deposited on unheated glass substrates and their structure was characterized by x-ray diffraction and surface morphology by atomic force microscopy. Special attention is devoted to the measurement of Tsurf using thermostrips pasted to the glass substrate. It was found that (1) Tsurf is considerably higher (approximately by 100°C or more) than the substrate temperature Ts measured by the thermocouple incorporated into the substrate holder and (2) Tsurf strongly depends on the substrate-to-target distance ds-t, the magnetron target power loading, and the thermal conductivity of the target and its cooling. The main result of this study is the finding that (1) the crystallization of sputtered TiO2 films depends not only on Tsurf but also on the total pressure pT of sputtering gas (Ar+O2), partial pressure of oxygen pO2, the film deposition rate aD, and the film thickness h, (2) crystalline TiO2 films with well developed anatase structure can be formed at Tsurf=160°C and low values of aD≈5nm∕min, (3) the crystalline structure of TiO2 film gradually changes from (i) anatase through (ii) anatase+rutile mixture, and (iii) pure rutile to x-ray amorphous structure at Tsurf=160°C and pT=0.75Pa when pO2 decreases and aD increases above 5nm∕min, and (4) crystallinity of the TiO2 films decreases with decreasing h and Tsurf. Interrelationships between the structure of TiO2 film, its roughness, Tsurf, and aD are discussed in detail. Trends of next development are briefly outlined.
Plasma etching of benzocyclobutene in CF4∕O2 and SF6∕O2 plasmas
Authors: Kim G. S. , Steinbrüchel C.
Published: May 2006

Results for the reactive ion etching and patterning of benzocyclobutene (BCB) in CF4∕O2 and SF6∕O2 plasmas in a parallel-plate reactor with Langmuir probe and optical emission diagnostics are reported. The behavior of the O atom concentration [O] is similar in both plasmas, showing a strong maximum at a concentration of about 70% O2. The F atom concentration [F] has a maximum at 30% O2 in CF4∕O2, but the etch rate has a maximum at 70% O2. In SF6∕O2, by contrast, [F] and the etch rate increase continuously as the SF6 content is increased, and the highest etch rate is obtained with pure SF6. Also, BCB etched in pure SF6 gives a very smooth surface. Patterning is performed using two different masks: a conventional hard mask with Si oxide as the top layer and a different type of mask with BCB itself as the top layer. The anisotropy of the etching is evaluated in terms of the plasma conditions and type of masking. The aspect ratio dependence of the etch rate is investigated up to an aspect ratio of 2.5. The results are discussed in terms of possible etch mechanisms and their differences between SF6∕O2 and C4∕O2 plasmas. A simple model is used to show how the latter mask reduces the dependence of the etch rate on the aspect ratio.
Electrical property improvements of yttrium oxide-based metal-insulator-metal capacitors
Authors: Durand C. , Vallée C. , Dubourdieu C. , Kahn M. , Derivaz M. , Blonkowski S. , Jalabert D. , Hollinger P. , Fang Q. , Boyd I. W.
Published: May 2006

We investigate the effects of the thickness reduction and specific postannealing treatments in order to improve the electrical properties of yttrium oxide-based metal-insulator-metal (MIM) capacitors. The films were grown on Si∕TiSi2∕TiN substrates at 350°C by a low temperature process (pulsed liquid injection plasma-enhanced metal organic chemical vapor deposition). Although the thickness reduction leads to an increase of the capacitance density, the other electrical characteristics (the voltage linearity, the leakage currents, and the voltage breakdown) are seriously deteriorated due to the augmentation of the electric field. Low thermal budget annealing posttreatments (⩽450°C) were carried out in a gas flux (Ar, O2, and H2) and under an ultraviolet (UV) radiation (O2 and N2). We demonstrate that the UV-O2 annealing treatment is particularly efficient in improving the voltage linearity, the leakage currents, and the electric field breakdown. The improved electrical properties after the UV-O2 annealing can be related to chemical modifications (organic content reduction and oxygen content increase). The voltage linearity improvement is most likely due to the presence of a residual oxidized silicon ultrathin layer on the top surface of the yttrium oxide films. Thus, a UV-O2 annealing is an effective postdeposition treatment that is compatible with the low thermal budget, which is required for MIM applications.
Evaluation of complementary metal-oxide semiconductor based photodetectors for low-level light detection
Authors: Ardeshirpour Yasaman , Deen M. Jamal , Shirani Shahram
Published: May 2006

Current low-level light detection technologies for biomedical applications such as DNA microarray sensors use charge-coupled devices or photomultiplier tubes which cannot be easily integrated with electronic circuits on a chip. Complementary metal-oxide semiconductor (CMOS) image sensors do allow for the integration of photosensitive and signal processing elements on the same chip. However, more research is required if optimized low-level light detectors in standard CMOS technologies are to be developed. In this research, we have investigated different photosensitive devices, including vertical, lateral, and avalanche photodiodes and two floating gate-well-tied phototransistors with different gate oxide thicknesses. The photodetectors were fabricated in a commercial 0.18μm CMOS technology, and their optoelectronic characteristics were measured to determine the optimum configuration for low-level light detection.