bluuebunny/crossref_metadata_2025 huggingface dataset:
Association of the Endogenous Nitric Oxide Synthase Inhibitor ADMA With Carotid Artery Intimal Media Thickness in the Framingham Heart Study Offspring Cohort
Authors: Maas Renke , Xanthakis Vanessa , Polak Joseph F. , Schwedhelm Edzard , Sullivan Lisa M. , Benndorf Ralf , Schulze Friedrich , Vasan Ramachandran S. , Wolf Philip A. , Böger Rainer H. , Seshadri Sudha
Published: June 2009

Background and Purpose—

Higher plasma concentrations of the endogenous nitric oxides synthase inhibitor asymmetrical dimethylarginine (ADMA) are associated with increased risk of cardiovascular and cerebrovascular events and death, presumably by promoting endothelial dysfunction and subclinical atherosclerosis. We hypothesized that plasma ADMA concentrations are positively related to common carotid artery intimal-media thickness (CCA-IMT) and to internal carotid (ICA)/bulb IMT.

Methods—

We investigated the cross-sectional relations of plasma ADMA with CCA-IMT and ICA/bulb IMT in 2958 Framingham Heart Study participants (mean age, 58 years; 55% women).

Results—

In unadjusted analyses, ADMA was positively related to both CCA-IMT (β per SD increment, 0.012;
P
<0.001) and ICA/bulb IMT (β per SD increment, 0.059;
P
<0.001). In multivariable analyses (adjusting for age, sex, systolic blood pressure, antihypertensive treatment, smoking status, diabetes, BMI, total-to-HDL cholesterol ratio, log C-reactive protein, and serum creatinine), plasma ADMA was not associated with CCA-IMT (
P
=0.991), but remained significantly and positively related to ICA/bulb IMT (β per SD increment, 0.0246;
P
=0.002).

Conclusions—

In our large community-based sample, we observed that higher plasma ADMA concentrations were associated with greater ICA/bulb IMT, but not with CCA-IMT. These data are consistent with the notion that ADMA promotes subclinical atherosclerosis in a site-specific manner, with a greater proatherogenic influence at known vulnerable sites in the arterial tree.
Emerging Adults With Psychiatric Disabilities Involved With the Criminal Justice System
Authors: Hartwell Stephanie W. , Fisher William H. , Davis Maryann
Published: June 2009

Experiencing serious psychiatric problems during the transition from adolescence to adulthood intensifies the perils emerging adults confront. Emerging adults whose childhood and adolescent experiences include significant contact with the public mental health or criminal justice systems have numerous additional hurdles to overcome. Disruptions in education, few opportunities for involvement with nonpsychiatrically involved peers, and limited life experiences reflect difficulties developing normative social control, skills, and networks. This article examines the impact of age and multiple stigmatized statuses by comparing an emerging adult and older cohort of psychiatrically disabled offenders. It explores whether there are features (demographic, clinical, and criminal ) that distinguish emerging adults that should be considered in creating appropriate community services for treatment and prevention and subsequent desistance from continued criminal involvement.
Exploring Factors Associated With Turnover Among Registered Nurse (RN) Supervisors in Nursing Homes
Authors: Kash Bita A. , Naufal George S. , Cortés Leslie , Johnson Christopher E.
Published: June 2009

Because most turnover studies focus on certified nursing assistants (CNAs), licensed vocational nurses (LVNs), and administrators, little is known about registered nurses’ (RNs) higher turnover. This study builds on the current body of knowledge about turnover among RN supervisors in nursing homes. The article discusses a survey of RN nurse supervisors administered in more than 1,000 nursing homes that was merged with the 2003 Texas Medicaid cost report and the area resource file. Two 2-stage models are developed to predict RN turnover rates. RNs’ intent to leave predicts RN turnover through job satisfaction, perceived empowerment, and education level. High LVN and CNA turnover and high Medicare census are associated with higher turnover. Implications are that participation in management decisions and perceived wage competitiveness are an important determinant of RN retention in nursing homes. Future research should focus why RN supervisors with higher levels of education leave nursing homes.
Interprofessional Collaboration on Sexual Assault Response Teams (SART)
Authors: Cole Jennifer , Logan T.K.
Published: June 2009

The purpose of this study was to examine the role of victim alcohol use and partner—perpetrator on interprofessional collaboration on Sexual Assault Response Teams (SART). Telephone surveys with 78 medical, criminal justice, and victim advocacy professionals were conducted. When asked to identify case factors that pose challenges to interprofessional collaboration, 48.7% mentioned victim characteristics and 28.2% mentioned situation characteristics. Significantly more victim advocates identified aspects of the victim’s behavior before the sexual assault as a challenge to collaboration compared to criminal justice professionals. Using vignette methodology, professionals anticipated more disagreement between SART professionals on the hypothetical case involving victim alcohol use and a partner—perpetrator compared to a hypothetical stranger/no alcohol case, with victim advocates rating agreement significantly lower than other professionals. Finally, professionals who perceived of more disagreement between professionals when discussing the vignettes also perceived of lower interprofessional collaboration on their SART. Implications for practice and research are discussed.
Development of paroxysmal nocturnal haemoglobinuria in systemic lupus erythematosus: an unusual cause of portal vein thrombosis
Authors: Gupta A , Al Fulaij R , Gupta RK , Gupta G , Marouf R
Published: June 2009

We report a case of a 60 year-old female with systemic lupus erythematosus (SLE) who was being managed with low-dose oral prednisolone. Four years later, she was admitted with pain in upper abdomen of 1 week duration. It was associated with ascitis and thrombocytopenia. Radiological investigations revealed portal vein thrombosis. There were no known local thrombophilic risk factors. Investigations ruled out any associated inherited or acquired hypercoagulable states. To evaluate the cause of thrombocytopenia, bone marrow aspiration was performed. Cells were subjected to flow cytometric examination, which revealed deficiency of CD55 and CD59 on granulocytes, indicating that a clone of cells with paroxysmal nocturnal haemoglobinuria had developed in this patient which had resulted in portal vein thrombosis. At this juncture, Ham test was also positive. The importance of considering rare possibilities of thrombosis at unusual site in patients with SLE is highlighted.
Clinical manifestations and outcomes of antithrombotic treatment of the Tan Tock Seng Hospital Singapore antiphospholipid syndrome cohort
Authors: Tan BE , Thong BYH , Shivananda S , Han WW , Chng HH
Published: June 2009

To examine the clinical manifestations, intensity of oral anticoagulation and outcomes in the prevention of recurrent thromboses in patients with antiphospholipid syndrome (APS) in a tertiary rheumatology centre in Singapore. Retrospective case review of consecutive patients with APS attending a rheumatology clinic from 1st January 2004 to 31st December 2005. There were 59 (44%) patients with definite APS and 75 (56%) with probable APS. Systemic lupus erythematosus (SLE) was the most common cause of secondary APS. Hypertension and hyperlipidaemia were the most common cardiovascular comorbidities. The most common manifestations were haematological (thrombocytopaenia and haemolytic anaemia), neurological (seizure, headache) and pulmonary hypertension. Among those with definite APS, there were similar proportions with arterial and venous thromboses. Recurrent thromboses occurred in 14 (23.7%) patient with definite APS receiving warfarin, comprising 14 (73.7%) episodes of arterial and 5 (26.3%) episodes of venous thromboses. Recurrent arterial thromboses occurred at international normalized ratio (INR) of <2 in 5 (35.7%), INR 2–3 in 6 (42.9%), INR > 3 in 3 (21.4%) episodes, respectively. Recurrent venous thromboses occurred at INR < 2 in 4 (80.0%) and INR > 3 in 1 (20.0%) episode, respectively. Twenty-eight episodes of bleeding occurred in 21 (35.6%) patients, the majority (78.6%) being minor bleeding. Two-thirds of all major bleeds occurred at INR ≥ 3. Venous and arterial thromboses were equally common in our patients with definite APS, although recurrent thromboses were more common in the arterial circulation. Target INR > 3 was associated with lower rates of recurrent arterial thromboses but higher rates of major and recurrent bleeding. Target INR ≥ 2 appeared to be sufficient to prevent recurrent venous thromboses.
Defect Identification in Electrical Circuits via the Virtual Distortion Method. Part 1: Steady-state Case
Authors: Kokot Marek , Holnicki-Szulc Jan
Published: June 2009

Virtual Distortion Method, a numerical technique originally developed and applied to various optimization problems in structural mechanics, is adapted to DC/AC circuit analysis. Electro-mechanical analogies with discrete models of plain truss structures are utilized to introduce and implement the main concepts of the method. Simulation of conductance modifications in circuit elements by the equivalent set of virtual sources is a foundation of numerically effective algorithms enabling fast re-analysis and sensitivity analysis. Inverse problem of defect identification is discussed and solution based on distortion approach is provided.
First-in-man use of polymer-free valsartan-eluting stents in small coronary vessels: a comparison to polymer-free rapamycin (2%)-eluting stents
Authors: Peters Stefan , Behnisch Boris , Heilmann Torsten , Richter Christian
Published: June 2009

Introduction. Orally administered angiotensin receptor antagonists administered after bare-metal stent implantation and even after drug-eluting stent implantation seem to lower in-stent restenosis rates.Whether valsartan-eluting stents are similarly effective was tested here in a first-in-man trial.

Materials and methods. The efficacy of a polymer-free drug-eluting stent coated with 300 mcg valsartan was compared to a coating with a 2% rapamycin solution in small (≤ 2.5 mm) coronary vessels with and without oral valsartan on the basis of the YUKON Choice stent system (Translumina GmbH, Hechingen, Germany). Fifteen patients (eight males, mean age 64.4±7.7 years) were treated with YUKON Choice valsartan-eluting stents and 30 patients (24 males, mean age 65.7±8.4 years) received YUKON Choice rapamycin-eluting stents. Clopidogrel was given for six months in all patients.

Results. Within the first 30 days, no adverse events occurred in either group. Binary in-stent restenosis rate was 30.8% (four in 13 angiographic controls) in the valsartan-eluting stent group and 35.0% (eight in 20 angiographic controls) in the rapamycin-eluting YUKON Choice stent group. Mean late lumen loss was 0.78±0.53 mm and 0.79±0.58 mm, respectively. Target lesion and target vessel revascularisation rate was 26.6% and 25.0%, respectively. No restenoses in rapamycin-eluting YUKON Choice stents appeared in 12 patients with adjunct oral valsartan administration.

Conclusions. If polymer-free YUKON Choice stents are used in small vessels, valsartan-eluting stents show an identical efficacy as rapamycin-loaded stents. In patients with rapamycin-eluting YUKON Choice stents it seems that the efficacy can be increased by oral valsartan administration.
Renin-angiotensin system polymorphisms and the association between use of angiotensin II receptor blockers or angiotensin-converting enzyme inhibitors and the risk of diabetes
Authors: Bozkurt Özlem , de Boer Anthonius , Grobbee Diederik E , Kroon Abraham A , Schiffers Paul , de Leeuw Peter , Klungel Olaf H
Published: June 2009

Introduction. We assessed the influence of genetic polymorphisms in the renin-angiotensin system on the risk of diabetes associated with the use of angiotensin II receptor blockers and angiotensin-converting enzyme (ACE) inhibitors.

Materials and methods. We performed a matched case-control study among antihypertensive drug users. Pharmacy records and questionnaires were used to ascertain incident diabetes (cases), antihypertensive drug use, and risk factors. Controls did not (yet) have diabetes.We genotyped ACE (G4656C, which is in complete linkage disequilibrium with the ACE insertion/deletion polymorphism), angiotensinogen (M235T), and angiotensin II type 1 receptor (A1166C).

Results. Among 495 cases of incident diabetes and 2,624 controls, homozygous 1166C carriers of angiotensin II type 1 receptor who used angiotensin II receptor blockers had an increased risk of diabetes compared to 1166A carriers (interaction odds ratio 5.3 [95% confidence interval: 1.8-16.1]). Homozygous ACE GG subjects who used ACE inhibitors ≥ 1 defined daily dose/day had a higher risk of diabetes compared to subjects with the ACE C allele (interaction odds ratio 2.3 [95% confidence interval: 1.2-4.5]).

Conclusions. Angiotensin II receptor blockers increase the occurrence of diabetes in homozygous 1166C carriers of angiotensin II type 1 receptor, but not in 1166A carriers. ACE inhibitors at doses ≥ 1 defined daily dose/day increase the risk of diabetes among homozygous ACE GG carriers, but not in 4656C carriers.
Angiotensin-converting enzyme gene insertion/deletion polymorphism in Egyptian patients with myocardial infarction
Authors: Settin Ahmad , ElBaz Rizk , Abbas Amr , Abd-Al-Samad Ayman , Noaman Ahmed
Published: June 2009

Introduction. This work aimed to test the association of the angiotensin-converting enzyme gene insertion/deletion (I/D) polymorphism with myocardial infarction.

Subjects and methods. This study comprised 79 Egyptian myocardial infarction cases with a mean age of 54.4±9.9 years including 60 males and 19 females, plus 238 healthy unrelated individuals of nearly matched age and sex as a control group. For all subjects, DNA testing for the angiotensin-converting enzyme gene I/D polymorphism was done using PCR amplification for detection of both the D and I alleles followed by a second run PCR specific for the I allele for samples typed as DD in the first run.

Results. Cases had a higher frequency of DD (29.1%) and ID (62.0%) genotypes than II (8.9%) genotype, with a higher frequency of D allele than I allele (64.4% vs. 33.6%). Compared to controls, cases had a significantly higher frequency of ID genotype (62.0% vs. 47.5%, p<0.05).This was more apparent among cases in the low risk group (p=0.002) than in the high risk group (p=0.041).

Conclusion. The angiotensin-converting enzyme gene I/D polymorphism is probably a risk factor for ischaemic heart disease among Egyptian cases, particularly if integrated with other environmental and genetic risk factors.
Enhanced cerebrovascular expression of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 via the MEK/ERK pathway during cerebral ischemia in the rat
Authors: Maddahi Aida , Chen Qingwen , Edvinsson Lars
Published: June 2009

Background

Cerebral ischemia is usually characterized by a reduction in local blood flow and metabolism and by disruption of the blood-brain barrier in the infarct region. The formation of oedema and opening of the blood-brain barrier in stroke is associated with enhanced expression of metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1).

Results

Here, we found an infarct volume of 24.8 ± 2% and a reduced neurological function after two hours of middle cerebral artery occlusion (MCAO), followed by 48 hours of recirculation in rat. Immunocytochemistry and confocal microscopy revealed enhanced expression of MMP-9, TIMP-1, and phosphorylated ERK1/2 in the smooth muscle cells of the ischemic MCA and associated intracerebral microvessels. The specific MEK1/2 inhibitor U0126, given intraperitoneal zero or 6 hours after the ischemic event, reduced the infarct volume significantly (11.8 ± 2% and 14.6 ± 3%, respectively; P < 0.05), improved neurological function, normalized expression of phosphorylated ERK1/2, and reduced expression of MMP-9 and TIMP-1 in the vessel walls. Administration of U0126 12 hours after MCAO did not alter the expression of MMP-9. Immunocytochemistry showed no overlap in expression between MMP-9/TIMP-1 and the astrocyte/glial cell marker GFAP in the vessel walls.

Conclusion

These data are the first to show that the elevated vascular expression of MMP-9 and TIMP-1, associated with breakdown of the blood-brain barrier following focal ischemia, are transcriptionally regulated via the MEK/ERK pathway.
Multi-resistant Escherichia coli and mycotic aneurysm: two case reports
Authors: McCann John F , Fareed Azhar , Reddy Sukanya , Cheesbrough John , Woodford Neil , Lau Sally
Published: June 2009

Introduction

Mycotic aneurysms account for a small proportion of all aneurysms. Escherichia coli a gram-negative organism, is recognised as a rare cause of aortic aneurysm. We report two cases of mycotic aneurysm caused by the same strain of multi-resistant Escherichia coli. The purpose of this case report is to highlight the possibility that this strain may be associated with an increased risk of endovascular infection especially in extra-aortic sites. These aneurysms can be difficult to detect and can have serious consequences.

Case presentation

In case one, the patient presented with symptoms and signs of septicaemia secondary to a urinary tract infection. Despite adequate treatment the patient continued with pyrexia and raised inflammatory markers, therefore a series of CT scans of the abdomen and thorax were performed, which revealed two intra-thoracic pseudo-aneurysms with associated haematomas. In case two, the patient also developed Escherichia coli septicaemia. On day 44 he developed a swelling on the right side of his neck. An ultrasound scan showed a pseudoaneurysm of the right common carotid artery.

Conclusions

Whilst a case report cannot prove that a heightened risk exists, we suggest that it is an area worthy of further surveillance. We recommend when older patients with atheromatosis develop prolonged Escherichia coli septicaemia, the possibility of an infected aneurysm should be borne in mind.
Epigenetic Control of Sexual Differentiation of the Bed Nucleus of the Stria Terminalis
Authors: Murray Elaine K. , Hien Annie , de Vries Geert J. , Forger Nancy G.
Published: June 2009

The principal nucleus of the bed nucleus of the stria terminalis (BNSTp) is larger in volume and contains more cells in male than female mice. These sex differences depend on testosterone and arise from a higher rate of cell death during early postnatal life in females. There is a delay of several days between the testosterone surge at birth and sexually dimorphic cell death in the BNSTp, suggesting that epigenetic mechanisms may be involved. We tested the hypothesis that chromatin remodeling plays a role in sexual differentiation of the BNSTp by manipulating the balance between histone acetylation and deacetylation using a histone deacetylase inhibitor. In the first experiment, a single injection of valproic acid (VPA) on the day of birth increased acetylation of histone H3 in the brain 24 h later. Next, males, females, and females treated neonatally with testosterone were administered VPA or saline on postnatal d 1 and 2 and killed at 21 d of age. VPA treatment did not influence volume or cell number of the BNSTp in control females but significantly reduced both parameters in males and testosterone-treated females. As a result, the sex differences were eliminated. VPA did not affect volume or cell number in the suprachiasmatic nucleus or the anterodorsal nucleus of the thalamus, which also did not differ between males and females. These findings suggest that a disruption in histone deacetylation may lead to long-term alterations in gene expression that block the masculinizing actions of testosterone in the BNSTp.
Metal-insulator transition and the character of the hole impurity bands in ferromagnetic GaMnAs disordered dilute magnetic semiconductor
Authors: Neves R. da Silva , Silva A. Ferreira da , Kishore R.
Published: June 2009

The study of ferromagnetic transition of Ga1-xMnxAs dilute magnetic semiconductor (DMS) is much of interest mainly due to the potential application in spintronic devices. Based on the mean field approach we present the average contribution of the hole spins by considering the holes in an impurity band (IB) and the critical concentration for the metal-insulator transition (MIT) in this semiconductor. In order to calculate the mean configuration of spins of impurities Mn+2 we use a formalism proposed for a spatial disordered system. The results for the metallic densities around the MIT transition are compared to experimental results and other theoretical findings.
The Contribution of Crystallinity to Tissue-level Properties in Modern and Fossilized Bone
Authors: Olesiak Sara E. , Sponheimer Matthew , Eberle Jaelyn J. , Ferguson Virginia L.
Published: June 2009

A range of mineral content values and organization of the collagen and mineral phases are possible contributors to the significant variance demonstrated within the nanomechanical behavior of mineralized tissues. A combined approach using nanoindentation, to assess nanomechanical behavior, and X-ray diffraction, for analysis of crystallinity and composition, were used to investigate a range of modern and fossilized bone samples. This work provides new insight into the functional role of organization and composition of the mineral phase within heterogeneous, mineralized materials of biological origin. While the predominant influence on nanomechanical behavior is made by mineral volume fraction, the crystallinity was shown to play a significant role in the nanomechanical behavior of modern and fossilized bone samples. The interplay between material structure and function will ultimately help to elucidate the relative contributions of various factors to nanomechanical behavior and lead to improved development of biomimetic materials.
Three-level hierarchal modeling of gecko toe adhesion
Authors: Chen B. , Wu P. D. , Gao H.
Published: June 2009

The underlying mechanisms of gecko adhesion have been investigated through modeling of the three-level hierarchical microstructures under gecko's toe [1]. At the bottom of hierarchy, we show that the peeling strength of a spatula pad for attachment can be 10 times larger than that for detachment. At the intermediate level of hierarchy, we show that the 10 times difference in the peeling strength of a spatula pad for attachment and detachment leads to a 100 times difference in adhesion energy at the level of seta. At the top of hierarchy, the attachment of a gecko toe is modeled as a pad under displacement controlled pulling, which yields an adhesive strength more than sufficient for gecko's body weight; On the other hand, the detachment is modeled as a pad under peeling, giving rise to a negligible peel-off force. The present study reveals that the hierarchical microstructures play critical roles in providing gecko with robust attachment and easy detachment.
Noise Spectra of Six Gey Bz:H Thermo-sensing Films for Micro-bolometers
Authors: Kosarev Andrey , Cosme Ismael , Torres Alfonso
Published: June 2009

Noise spectra in plasma deposited SixGeyBz:H thermo-sensing films for micro-bolometers have been studied. The samples were characterized by SIMS (composition) and conductivity (room temperature conductivity, activation energy) measurements. The noise spectra were measured in the temperature range from T= 300 K to T=400 K and in the frequency range from f=2 Hz to f=2×104 Hz. The noise spectra SI(f) for the samples Si0.11Ge0.88:H and Si0.04Ge0.71B0.23 can be described by SI(f) ˜ f– β with β = 1 and β = 0.4, respectively. For the sample Si0.06Ge0.67B0.26 two slopes were observed: in low frequency region f≤ 103 Hz β1= 0.7 and at higher frequencies f>103 Hz β2= 0.13. Increasing temperature resulted in an increase of noise magnitude and a change of β values. The latter depended on film composition. The correlation observed between noise and conductivity activation energies suggests that noise is due to bulk rather than interface processes. Noise spectrum of the thermo-sensing film Si0.11Ge0.88:H was compared with that for micro-bolometer structure with the same thermo-sensing film. The micro-bolometer structure showed higher noise value in entire frequency range that assumed additional processes inducing noise.
Microstructure and charge carrier transport in phthalocyanine based
Authors: Opitz Andreas , Wagner Julia , Ecker Bernhard , Hörmann Ulrich , Kraus Michael , Bronner Markus , Brütting Wolfgang , Hinderhofer Alexander , Schreiber Frank
Published: June 2009

The continuously growing and wide-spread utilization of blends of organic electron and hole conducting materials comprises ambipolar field-effect transistors as well as organic photovoltaic cells. Structural, optical and electrical properties are investigated in blends and neat films of the electron donor material Cu-phthalocyanine (CuPc) together with fullerene C60and Cu-hexadecafluorophthalocyanine (F16CuPc) as electron acceptor materials, respectively. The difference in molecular structure of the spherical C60and the planar molecule CuPc leads to nanophase separation in the blend, causing charge carrier transport which is limited by the successful formation of percolation paths. In contrast, blends of the similar shaped CuPc and F16CuPc molecules entail mixed crystals, as can be clearly seen by X-ray diffraction measurements. We discuss differences of both systems with respect to their microstructure as well as their electrical transport properties.
Three-Dimensional Organic Field-Effect Transistors: Charge Accumulation in their Vertical Semiconductor Channels
Authors: Uno M. , Doi I. , Takimiya K. , Takeya Jun
Published: June 2009

Three-dimensional organic field-effect transistors are developed with multiple vertical channels of organic semiconductors to gain high output current and high on-off ratio. High-mobility and air-stable dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene thin films deposited on horizontally elongated vertical sidewalls have realized unprecedented high output current per area of 2.6 A/cm2 with the application of drain voltage -10 V and gate voltage -20 V. The on-off ratio is as high as 2.7×106. Carrier mobility of the organic semiconductor deposited on the vertical sidewalls is typically 0.30 cm2/Vs. The structure is built also on plastic substrates, where still considerable current modulation is preserved with high output current per area of 70 mA/cm2 and with high on-off ratio of 8.7×106. The performance exceeds practical requirements for applications in driving organic light-emitting diodes in active-matrix displays. The technique of gating with electric double layers of ionic liquid is also introduced to the three-dimensional transistor structure.
Novel Magnetoresistive Structures Using Self-Assembly and Nanowires on Si
Authors: Maqableh Mazin , Huang Xiaobo , Stadler Beth
Published: June 2009

Anodic Aluminum Oxide (AAO) was grown both as free-standing membranes and as integrated layers on Si as templates for arrays of magnetoresistive nanowires. These structures will be useful for applications such as current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) sensors, magnetic random access memory (MRAM) and microwave oscillator arrays. As the AAO was formed, using a two-step anodization process, columnar nanopores self-assembled inside the oxide to form a close-packed array. The pore diameters could be varied from 10-60nm by changing the anodization conditions. As the diameter of the AAO nanopores decreased, the distance between the nanopores also decreased. The free-standing membranes had pores with lengths of 17um. The pores that were grown directly onto Si with an adhesion layer of Ti were 600nm in length. In addition to growing these latter pores directly onto Si, they were also grown onto Co/Cu/Co thin films that were evaporated onto the Si. Au nanocontacts were electroplated into these nanopores to study point-contact magnetoresistance and microwave response. For the magnetoresistive nanostructures, multilayered Co/Cu nanowires were fabricated via electrochemical deposition. The samples were measured with vibrating sample magnetometry (VSM) and also using ac and dc magnetotransport systems. The highest magnetoresistance was found in nanowires that had hysteresis loops that were identical as measured in plane and perpendicular to the plane. The highest measured MR (Delta R/R = 11%) of the multilayers was calculated as 33% by subtracting the resistance of the Cu leads on either side of the multilayers from the denominator. Shorter wires are currently under construction to avoid this effect. Spin transfer torque (STT) was also measured in the samples. For 10-60nm diameter nanowires, the change in resistance due to STT was around 6% which represents the full magnetoresistance of the larger wires, but only half that of the smaller nanowires. It is therefore concluded that the 10-nm Co layers do not align antiparallel to parallel as fully at the switching current density of JAP-P = 2.7 × 108 A/cm2 compared to the larger wires which switch at JAP-P = 3.2 × 107 A/cm2. With diameters in the 10-60 nm range and integration with Si, these nanostructures have great potential for future nanosensors, MRAM and microwave oscillator arrays.
Large Area Chemical Bath Deposition of CdS on Cu(InGa)Se2
Authors: Vora Nirav D , Repins Ingrid , Robbins Steve , Mann Johnathan , Castenada Hector , Armstrong Brian
Published: June 2009

Chemical bath deposition (CBD) is a commonly used method of depositing cadmium sulfide (CdS) films for photovoltaic application. The method is based on decomposition of a sulfur source in an alkaline solution of a cadmium source on the surface of the Cu(In,Ga)Se2 (CIGS) substrate. On the lab scale the CdS film is deposited by submerging a 1” square CIGS substrate in a heated beaker containing the chemical bath. This batch processing method is the one used for record-performing devices. There is an ongoing effort at the National Renewable Energy Laboratory to scale-up the CBD process to deposit CdS films on 6” square substrate. Efforts are focused at designing both batch and flow reactors for depositing uniform, device quality CdS films on larger substrates. Batch reactor designs involve reproducing the deposition process in the beaker on a bigger scale with minimal chemical waste, while flow reactors are designed for continuous processing, such as encountered in roll-to-roll manufacturing lines.
Titanium Incorporation to In2S3 Thin Films for Photovoltaic Applications
Authors: Asenjo Begoña , Herrero José , Gutiérrez M. Teresa
Published: June 2009

Preliminary studies on the properties of undoped and Ti-doped In2S3 thin films grown on soda lime glass by chemical solution deposition under different conditions are presented. Different physical, chemical and morphological properties of the films have been analysed. At the beginning of the deposition of In2S3 films, In2O3 and In(OH)3 deposited by electroless-chemical reaction are dominant. The optical properties observed for Ti-In2S3 films show the partial contribution of the electronic transitions. The study is completed with SEM analysis which shows the influence of the deposition time and the precursor used, in the morphology for incorporation of titanium at the beginning of deposition and X-ray diffraction when is observed the amorphous nature of the films.
Chlorine Doping of Cadmium Sulfide on the Example of CBD CdS
Authors: Jaan Hiie , Quinci Federico , Lughi Vanni , Sergo Valter , Valdna Vello , Mikli Valdek , Kärber Erki , Raadik Taavi
Published: June 2009

The role of thermal annealing and of CdCl2 as a main source of electrically active but vaporizable chlorine doping in chemical bath deposited CdS thin films is studied. The films were deposited on glass substrates from aqueous solution of either CdCl2, NH4Cl, NH4OH, and thiourea, or CdSO4, (NH4)2SO4, NH4OH, and thiourea. Films deposited in the presence of CdCl2 and annealed in H2 atmosphere at 310 and 420 °C show a resistivity lower than 10 Ω·cm, one order of magnitude less than for identically annealed films deposited in absence of CdCl2. Annealing at 420 °C in closed ampoules, where a counter pressure of CdCl2 builds up, leads to a lower resistivity on the order of 10−1 Ω·cm, confirming the key role of chlorine on the electronic properties. However, further characterization via photoluminescence raises new questions about chlorine-related defects and their role in the mechanisms that govern film resistivity.
Understanding Electrical Transport and the Large Power Factor Enhancements in Co-Nanostructured PbTe
Authors: Sootsman Joseph R , Jovovic Vladimir , Jaworski Christopher M , Heremans Joseph P , He Jiaqing , Dravid Vinayak P , Kanatzidis Mercouri G
Published: June 2009

We previously reported the synthesis of nanostructured composite PbTe with excess Pb and Sb metal inclusions. The electrical conductivity shows an unusual temperature dependence that depends on the inclusion Pb/Sb ratio, resulting in marked enhancements in power factor and ZT at 700 K. Additional investigation of the transport and structure of these materials is reported here. Measurements of the scattering parameter reveals there is little change in electron scattering with respect to pure PbTe. High resolution electron microscopy was used to determine additional information about the nature of the precipitate phases present in the samples. High temperature transmission electron microscopy reveals that the precipitates begin to dissolve at high temperatures and completely disappear at T > 619K. A qualitative explanation of the unusual transport behavior of these materials is presented.
Subwavelength Terahertz Waveguide Using Negative Permeability Metamaterial
Authors: Ishikawa Atsushi , Zhang Shuang , Genov Dentcho A , Bartal Guy , Zhang Xiang
Published: June 2009

We propose a novel subwavelength terahertz (THz) waveguide using the magnetic plasmon polariton (MPP) mode guided by a narrow gap in a negative permeability metamaterial. Deep subwavelength wave-guiding (< λ/10) with a modest propagation loss (2.5 dB/λ) and group velocities down to c/21.8 is demonstrated in a straight waveguide, a 90-degree bend, and a splitter. The distinctive dispersions of the guided mode with positive and negative group velocities are explained analytically by considering the dispersive effective optical constants of the metamaterial. The proposed waveguiding system inherently has no cutoff for any core width and height, paving the way toward the deep subwavelength transport of THz waves for integrated THz device applications.
Wood and Paper as Materials for the 21st Century
Authors: Jones Philip , Wegner Theodore H
Published: June 2009

Wood and paper are ubiquitous in societies around the world and are largely taken for granted as part of traditional industries with no new science to learn. Many of the technologies used in the forest products industry have been gained empirically through experience. The complexities of wood are now yielding to newer tools and we are beginning to see how the mechanical, optical and other physical properties of wood are related to hierarchical structures based on 2 to 10 nm diameter several hundred nm long fibers of nanocrystalline cellulose (NCC). The liberation of these NCC’s is allowing their re-assembly into remarkably strong structures. Examples will be given of the nature of these building blocks and structures assembled from them. Examples will include nanocomposites as well as very high strength “paper”. Paper is another example of a process whereby nanofibrils are released and then re-assembled with the use of “retention, drainage and formation aides” to make substrates we call paper with remarkable strength to weight performance. Other disciplines call this process “self-assembly” and the “aids” as necessary surfactants and additives to control structure and performance. Glossy magazine papers, for example, have approximately 10 micron thick coatings of white minerals and latex binders which are increasingly of nano dimensions. The coatings are assembled in structures to provide optical barrier performance (opacity) as well as controlled ink interaction with the necessary strength to survive printing and handling. These coatings are frequently similar in structure to seashells and, from this knowledge, progress has been made in understanding the mechanisms at play in achieving higher strength coatings. More recently kaolin clays have been introduced with mean crystal thicknesses in the range 20 to 40 nm instead of the usual 100 to 140 nm. These clays show useful strength performance and represent what may be called pragmatic nanoclays. Novel chemistries based on biomimetic learnings are emerging to displace the conventional starch or latex binders. Examples will be given of protocols for moving toward higher strength systems.
Magnetotactic Bacteria – a Natural Architecture Leading from Structure to Possible Applications
Authors: Zhang Kui Yu , Zhu Kai Ling , Xiao Tian , Wu Long Fei
Published: June 2009

Magnetotactic bacteria are aquatic micro-organisms which have the specific capacity to navigate along the lines of the earth’s magnetic field. This property is related to the formation of chains of magnetic crystals calledmagnetosomes. All magnetotactic bacteria synthesize nano-sized intracellular magnetosomes that are surrounded by ultra-thin bio-membranes. The magnetosome chains serve as compass for navigation of the magnetotactic bacteria, and the cell flagella are considered as the mechanism for propelling the bacteria forward. This presentation describes various functions of the architectured structure of magnetotactic bacteria as well as their possible applications in biotechnology.
Fabrication of Ionic Polymer Metal Composite Actuator with Palladium Electrodes and Evaluation of its Bending Response
Authors: Kobayashi Takuma , Kuribayashi Takeshi , Omiya Masaki
Published: June 2009

We built up the way of fabricating IPMC actuator with palladium electrodes and we found that it showed large bending response than Au-plated IPMC actuator. An ionic polymer-metal composite (IPMC) consisting of a thin perfuorinated ionomer membrane, electrodes plated on both faces, undergoes large bending motion when a small electric field is applied across its thickness in a hydrated state. The characteristics of IPMC are ease of miniaturization, low density, and mechanical flexibility. Therefore, it is considered to have a wide range of applications from MEMS sensor to artificial muscle. However, there are problems on IPMC. First, its mechanical and electric characteristics have not been clarified because of the complex mechanism of the deformation. Second, it is high-priced because most of IPMC actuators use gold or platinum as electrodes. In order for IPMC actuator to be widely put to practical use, we should solve these problems. Hence, this research focuses on fabrication of IPMC actuator with palladium electrode, which is cheaper than gold or platinum, and evaluation of its mechanical properties such as its tip displacement. We fabricated IPMC consisting of a thin Nafion® membrane, which is the film with fluorocarbon back-bones and mobile cations, sandwiched between two thin palladium plates. The surface resistivity was 2.88±0.18Ω/sq., so it could be said to be enough small. Then, we observed its cross section by using FE-SEM. As a result, palladium plates were evenly coated and its thickness was about 30μm. Also, we carried out an actuation test for two kinds of IPMCs: one was fabricated by using Nafion®117 (thickness 183μm), the other was by Nafion®115 (thickness 127μm). In this test, the relationship between voltage (0˜4V) across its thickness and tip displacement for the cantilevered strip of the IPMC was measured. Then we found that IPMCs showed large bending motion under a low electric field. When Nafion®117 sample was subjected to voltage of 1.5V, the ratio of the tip displacement to the sample length was 0.35, which was lager bending than Au-plated IPMC actuator, whose ratio of the tip displacement to the sample length was 0.12 [1]. When Nafion®115 sample was applied to 1.5V, the ratio of the tip displacement to the sample length was 0.22. Then, we found that Nafion®117 bended in a larger way than Nafion®115. Reference [1]Sia Nemat-Nesser and Yongxian Wu,”Comparative experimental study of ionic polymer-metal composites with different backbone ionomers and in various cation forms”, Journal of Applied Physics,93,5255 (2003)
Uso de serviços básicos de saúde por idosos portadores de condições crônicas, Brasil
Authors: Rodrigues Maria Aparecida P , Facchini Luiz Augusto , Piccini Roberto Xavier , Tomasi Elaine , Thumé Elaine , Silveira Denise Silva , Siqueira Fernando Vinholes , Paniz Vera Maria Vieira
Published: June 2009

OBJETIVO: Avaliar a utilização de serviços de saúde entre idosos portadores de doenças crônicas. MÉTODOS:Estudo transversal realizado com 2.889 indivíduos com idade a partir de 65 anos, portadores de condições crônicas - hipertensão arterial, diabetes mellitus e doença mental -, residentes em áreas de abrangência de unidades básicas de saúde em 41 municípios das regiões Sul e Nordeste do Brasil em 2005. Os dados analisados foram obtidos do estudo de linha de base do Programa de Expansão e Consolidação da Saúde da Família. As variáveis estudadas foram sexo, idade, cor da pele, situação conjugal, escolaridade, renda familiar, tabagismo, incapacidade funcional e modelo de atenção da unidade básica de saúde. A análise ajustada dos desfechos foi realizada com regressão de Poisson. RESULTADOS: A prevalência de consulta médica nos últimos seis meses foi de 45% no Sul e de 46% no Nordeste. A prevalência de participação em grupos de atividades educativas no último ano foi de 16% na região Sul e de 22% na região Nordeste. Nas duas regiões, o uso dos serviços foi maior por idosos com idade inferior a 80 anos, baixa escolaridade e residentes em áreas de abrangência de unidades básicas de saúde com Programa Saúde da Família. Apenas na região Sul os idosos com incapacidade funcional apresentaram maior prevalência de consultas médicas. CONCLUSÕES: As prevalências de consulta médica e de participação em grupos de atividades educativas foram baixas, quando comparadas com estudos anteriores realizados com idosos no Brasil. Os resultados indicam que, apesar de o Programa Saúde da Família promover maior uso de serviços das unidades básicas de saúde pelos idosos portadores de condições crônicas, há necessidade de ampliar o acesso daqueles com mais de 80 anos e dos portadores de incapacidade funcional.
Gêneros Euastrum Ehrenberg ex Ralfs e Micrasterias C. Agardh (Conjugatophyceae-Desmidiaceae) de dois ambientes amazônicos de águas pretas (Manaus, Amazonas-Brasil)
Authors: Melo Sérgio , Souza Karla F. , Rebelo Sérgio R.M. , Sophia Maria da Graça
Published: June 2009

Foi realizado um inventário das espécies dos gêneros Euastrum Ehrenberg ex Ralfs e Micrasterias C.Agardh de dois ambientes de águas pretas do município de Manaus, um lago de inundação (lago Tupé), e o rio Negro. As coletas foram realizadas com rede de plâncton em quatro estações no lago e uma no rio Negro, situada próxima ao lago. Um total de 93 amostras foi analisado, coletadas em escala mensal no período de março de 2002 a outubro de 2003. As espécies foram descritas e ilustradas com base na sua morfologia e morfometria. Um total de 12 espécies foi identificado, sendo cinco do gênero Euastrum (E. evolutum var. perornatum; E. gemmatum var. monocyclum; E. ornans; E. sinuosum e E. spinulosum), e sete do gênero Micrasterias (M. borgei; M. radiata var. brasiliensis; M. torreyi; M. laticeps var. acuminata; M. mahabuleshwarensis var. amazonensis; M. rotata var. rotata; M. siolii). Todas as espécies, exceto M. radiata Hassal var. brasiliensis Grönblad, foram registradas no rio Negro, enquanto no lago Tupé foi registrado, no geral, apenas sete espécies, três de Euastrum e quatro de Micrasterias.
Matéria orgânica em solos desenvolvidos de rochas máficas no nordeste de Roraima
Authors: Melo Valdinar Ferreira , Schaefer Carlos Ernesto Gonçalves Reynaud
Published: June 2009

Solos desenvolvidos de rochas máficas no nordeste de Roraima são cultivados continuamente por populações indígenas em função da boa fertilidade natural. Este trabalho objetivou avaliar as alterações na matéria orgânica do solo por meio do fracionamento das substâncias húmicas, aplicação de análises de CHNS, estudos termogravimétricos e de Ressonância Paramagnética de Elétrons (EPR). Os maiores teores de C foram observados no Chernossolo sob cultivo contínuo. A fração humina foi predominante em todos os solos, tendo seus teores reduzidos em profundidade. No Nitossolo, houve menor relação ácido húmico/fúlvico. No Chernossolo cultivado, a posição no relevo e a incorporação dos restos culturais parece ter contribuído para manter a estabilidade do solo. Nos demais Chernossolos, a natureza química contribuiu para a ciclagem mais eficiente da matéria orgânica. No Chernossolo e nos Cambissolos não cultivados, a matéria orgânica se apresentou menos estável. No Chernossolo sob cultivo, houve aumento da polimerização do ácido húmico. Os solos com horizonte A chernozêmico, não cultivados, comportaram-se mais uniformes quanto à qualidade dos ácidos húmicos.
Etnografia e manejo de recursos naturais pelos índios Deni, Amazonas, Brasil
Authors: Pezzuti Juarez , Chaves Rodrigo Pádua
Published: June 2009

São raros os estudos envolvendo o uso múltiplo de recursos naturais por populações amazônicas. Este trabalho apresenta um panorama de como os índios Deni, habitantes da região de interflúvio entre dois dos maiores afluentes de água branca da bacia amazônica, os rios Juruá e Purus, utilizam dos recursos disponíveis em seu território. Os Deni são, atualmente, índios que vivem da exploração de recursos da terra firme e de regiões alagadas. São um misto de horticultores e caçadores/coletores, que utilizam toda a sua área para a obtenção de recursos para subsistência. Como regra, deslocam periodicamente seus assentamentos, evitando o esgotamento local de recursos, e provocando a modificação local do ambiente. Esta alteração aumenta temporariamente a disponibilidade de alimento. Áreas com aldeias, pomares e roçados abandonados, por sua vez, tornam-se locais onde se concentram inúmeros recursos da flora e da fauna, posteriormente explorados. O impacto provocado por este sistema é aparentemente mínimo. Os Deni estão contextualizados na periferia de um sistema capitalista, onde a única fonte de renda para adquirir bens que são hoje considerados pelos índios como indispensáveis para sua sobrevivência são os recursos naturais. Estes são e continuarão sendo explorados de maneira a produzir um excedente a ser comercializado para a obtenção de uma série de produtos industrializados, independentemente das opiniões externas. É sobre este patamar que devemos avaliar a sustentabilidade do atual manejo da área.