bluuebunny/crossref_metadata_2025 huggingface dataset:
Annealing study of two-dimensional patterned Ge nanostructures via nanosphere lithography
Authors: Ulmeanu Magdalena , Iordache Iuliana , Filipescu Mihaela , Craciun Valentin , Pinzaru Simona , Hörner Andreas
Published: June 2011

Experimental studies on patterning hexagonal Ge nanostructures have been conducted on Si substrates through deposition of Ge with colloidal particles as a mask. The deposited Ge thin film possesses, according to the X-ray diffraction measurements, in plane texture, being epitaxial and aligned with the (111) Si substrate. The size distribution of the patterned Ge nanostructures is narrow, as indicated by the atomic force microscopy and scanning electron microscopy measurements. We have obtained Ge nanostructures with lateral dimension of 490 nm (height 12 nm), 200 nm (height 6 nm) and 82 nm (height 6 nm) by using different sizes of polystyrene spheres. We have performed in depth studies of the Ge nanostructures’ behavior due to thermal and rapid thermal post-annealing processes. FT micro-Raman spectroscopy shows that there is no Si intermixing during the annealing process. In order to quantify the changes in the height and lateral dimension, we have performed atomic force microscopy and white light interferometry analysis. The changes in shape and the decrease in the area of a cross-section of Ge nanostructure will be discussed in respect to similar results shown in the literature for Ge thin films during the annealing process.
Confinement, chiral symmetry, and the lattice
Authors: Creutz Michael
Published: June 2011

Confinement, chiral symmetry, and the lattice

Two crucial properties of QCD, confinement and chiral symmetry breaking, cannot be understood within the context of conventional Feynman perturbation theory. Non-perturbative phenomena enter the theory in a fundamental way at both the classical and quantum levels. Over the years a coherent qualitative picture of the interplay between chiral symmetry, quantum mechanical anomalies, and the lattice has emerged and is reviewed here.
Introduction to Integrable Many-Body systems III
Authors: Bajnok Zoltán , Šamaj Ladislav
Published: June 2011

Introduction to Integrable Many-Body systems III

This is the third part of a three-volume introductory course about integrable systems of interacting bodies. The emphasis is put onto the method of Thermodynamic Bethe ansatz. Two kinds of integrable models are studied. Systems of itinerant electrons, forming a part of Condensed Matter Physics, involve the Hubbard lattice model of electrons with short-ranged one-site interactions (Sect. 20) and the s-d exchange Kondo model (Sect. 21), describing the scattering of conduction electrons on a spin-s impurity. Methods and basic concepts used in Quantum Field Theory are explained on the integrable (1 + 1)-dimensional sine-Gordon model. We start with the classical description of the model in Sect. 22, analyze its finite energy field configurations (soliton, anti-soliton and breathers) and show its classical integrability. The model is quantized by using two schemes: the conformal (Sect. 23) and Lagrangian (Sect. 24) quantizations. The scattering matrix of the sine-Gordon theory is derived at the full quantum level in the bootstrap scheme and is compared to its classical limit in Sect. 25. The parameters of the scattering matrix are related to those of the Lagrangian by calculating the ground-state energy in an applied magnetic field in two ways: Conformal perturbation theory and Thermodynamic Bethe ansatz (Sect. 26). The relation of the sine-Gordon theory to the XXZ Heisenberg model, which provides a complete solution of the sine-Gordon model in a finite volume, is pointed out in Sect. 27. The obtained results are applied in Sect. 28. to the derivation of the exact thermodynamics for the (symmetric) two-component Coulomb gas; this is the first classical two-dimensional fluid with exactly solvable thermodynamics.
The Influence of the Load on the Hardness
Authors: Petrík Jozef , Palfy Pavol
Published: June 2011

The Influence of the Load on the Hardness

The objective of the submitted paper is to analyze the influence of the load on the calibration of micro-hardness and hardness testers. The results were validated by Measurement Systems Analysis (MSA), Analysis of Variance (ANOVA) and Z-score. The relationship between the load and micro-hardness in calibration of micro-hardness testers cannot be explained by Kick's Law (Meyer's index "n" is different from 2). The conditions of Kick's Law are satisfied at macro-hardness calibration, the values of "n" are close to 2, regardless of the applied load. The apparent micro-hardness increases with the increase of the load up to 30 g; the reverse indentation size effect (ISE) behavior is typical for this interval of the loads. The influence of the load on the measured micro-hardness is statistically significant for majority of calibrations.
An Idea of a Measurement System for Determining Thermal Parameters of Heat Insulation Materials
Authors: Chudzik Stanisław , Minkina Waldemar
Published: June 2011

An Idea of a Measurement System for Determining Thermal Parameters of Heat Insulation Materials

The article presents the prototype of a measurement system with a hot probe, designed for testing thermal parameters of heat insulation materials. The idea is to determine parameters of thermal insulation materials using a hot probe with an auxiliary thermometer and a trained artificial neural network. The network is trained on data extracted from a nonstationary two-dimensional model of heat conduction inside a sample of material with the hot probe and the auxiliary thermometer. The significant heat capacity of the probe handle is taken into account in the model. The finite element method (FEM) is applied to solve the system of partial differential equations describing the model. An artificial neural network (ANN) is used to estimate coefficients of the inverse heat conduction problem for a solid. The network determines values of the effective thermal conductivity and effective thermal diffusivity on the basis of temperature responses of the hot probe and the auxiliary thermometer. All calculations, like FEM, training and testing processes, were conducted in the MATLAB environment. Experimental results are also presented. The proposed measurement system for parameter testing is suitable for temporary measurements in a building site or factory.
Heart Segmentation in Echo Images
Authors: Skalski Andrzej , Turcza Paweł
Published: June 2011

Heart Segmentation in Echo Images

Cardiovascular system diseases are the major causes of mortality in the world. The most important and widely used tool for assessing the heart state is echocardiography (also abbreviated as ECHO). ECHO images are used e.g. for location of any damage of heart tissues, in calculation of cardiac tissue displacement at any arbitrary point and to derive useful heart parameters like size and shape, cardiac output, ejection fraction, pumping capacity. In this paper, a robust algorithm for heart shape estimation (segmentation) in ECHO images is proposed. It is based on the recently introduced variant of the level set method called level set without edges. This variant takes advantage of the intensity value of area information instead of module of gradient which is typically used. Such approach guarantees stability and correctness of algorithm working on the border between object and background with small absolute value of image gradient. To reassure meaningful results, the image segmentation is proceeded with automatic Region of Interest (ROI) calculation. The main idea of ROI calculations is to receive a triangle-like part of the acquired ECHO image, using linear Hough transform, thresholding and simple mathematics. Additionally, in order to improve the images quality, an anisotropic diffusion filter, before ROI calculation, was used. The proposed method has been tested on real echocardiographic image sequences. Derived results confirm the effectiveness of the presented method.
Highly Accurate Calibration System for Electronic Instrument Transformers
Authors: Tong Yue , Ye Guoxiong , Guo Keqin , Li Hongbin
Published: June 2011

Highly Accurate Calibration System for Electronic Instrument Transformers

A high accurate electronic instrument transformer calibration system is introduced in this paper. The system uses the fourth-order convolution window algorithm for the error calculation method. Compared with Fast Fourier Transform, which is recommended by standard IEC-60044-8 (Electronic current transformers), it has higher accuracy. The relative measuring errors caused by asynchronous sampling could be reduced effectively without any special hardware technique adopted. The results show that the ratio error caused by asynchronous sampling can be reduced to 10-4, and the phase error can be reduced to 10-3 degrees when the deviation of frequency is within ±0.5 Hz. The present method of measurement processing is achieved by a high-accuracy USB multifunction data acquisition (DAQ) card and virtual measurement devices, with low cost, short exploitation period and high stability.
The Grain Yield and Weed Infestation Rate of Winter Wheat by the Different Share of Cereals in Crop Rotations
Authors: Babulicová Mária , Mendel Ľubomír
Published: June 2011

The Grain Yield and Weed Infestation Rate of Winter Wheat by the Different Share of Cereals in Crop Rotations

The aim of the study was to compare the grain yield and weed infestation rate of winter wheat in crop rotations with 40, 60 and 80% share of cereals and in continuous cropping. The trial was situated in the area of continental climate. The trial had two parts. In the first part, there were crop rotations with 40, 60 and 80% share of the cereals. Two levels of fertilization were used: H1 mineral fertilization + organic manure Veget; H2 mineral fertilization only. In the second part, winter wheat and spring barley were grown in monoculture. Three variants of fertilization were used: 1 - mineral fertilization; 2 - mineral fertilization + straw of cereals were ploughed; 3 - mineral fertilization + straw of cereals + organic manure Veget were ploughed in the soil. In the years 2006-2009 the grain yield, thousand kernel weight and weed infestation rate of winter wheat in different crop rotations and by the continuous cropping were investigated. The statistically higher winter wheat grain yield (6.50 t ha-1) was recorded by 40% share of cereals in crop rotation than by 60% and 80% share of cereals (6.23 t ha-1). The grain yield of winter wheat by continuous cropping was lower by 2.24 t ha-1 (34.46%) than in crop rotation with 40% share of cereals. The weed infestation rate by 80% share of cereals in crop rotation was determined 2.4 times higher than by 40% share of cereals.
Hip Strengthening Prior to Functional Exercises Reduces Pain Sooner Than Quadriceps Strengthening in Females With Patellofemoral Pain Syndrome: A Randomized Clinical Trial
Authors: Dolak Kimberly L. , Silkman Carrie , McKeon Jennifer Medina , Hosey Robert G. , Lattermann Christian , Uhl Timothy L.
Published: June 2011

Study Design

Randomized clinical trial.

Objectives

To determine if females with patellofemoral pain syndrome (PFPS) who perform hip strengthening prior to functional exercises demonstrate greater improvements than females who perform quadriceps strengthening prior to the same functional exercises.

Background

Although PFPS has previously been attributed to quadriceps dysfunction, more recent research has linked this condition to impairment of the hip musculature. Lower extremity strengthening has been deemed an effective intervention. However, research has often examined weight-bearing exercises, making it unclear if increased strength in the hip, quadriceps, or both is beneficial.

Methods

Thirty-three females with PFPS performed either initial hip strengthening (hip group) or initial quadriceps strengthening (quad group) for 4 weeks, prior to 4 weeks of a similar program of functional weight-bearing exercises. Self-reported pain, function, and functional strength were measured. Isometric strength was assessed for hip abductors, external rotators, and knee extensors. A mixed-model analysis of variance was used to determine group differences over time.

Results

After 4 weeks, there was less mean ± SD pain in the hip group (2.4 ± 2.0) than in the quad group (4.1 ± 2.5) (P = .035). From baseline to 8 weeks, the hip group demonstrated a 21% increase (P<.001) in hip abductor strength, while that remained unchanged in the quad group. All participants demonstrated improved subjective function (P<.006), objective function (P<.001), and hip external rotator strength (P = .004) from baseline to testing at 8 weeks.

Conclusion

Both rehabilitation approaches improved function and reduced pain. For patients with PFPS, initial hip strengthening may allow an earlier dissipation of pain than exercises focused on the quadriceps.

Level of Evidence

Therapy, level 2b-. J Orthop Sports Phys Ther 2011;41(8):560–570. Epub 7 June 2011. doi:10.2519/jospt.2011.3499
Implicit Social Cognitions Predict Sex Differences in Math Engagement and Achievement
Authors: Nosek Brian A. , Smyth Frederick L.
Published: June 2011

Gender stereotypes about math and science do not need to be endorsed, or even available to conscious introspection, to contribute to the sex gap in engagement and achievement in science, technology, engineering, and mathematics (STEM). The authors examined implicit math attitudes and stereotypes among a heterogeneous sample of 5,139 participants. Women showed stronger implicit negativity toward math than men did and equally strong implicit gender stereotypes. For women, stronger implicit math=male stereotypes predicted greater negativity toward math, less participation, weaker self-ascribed ability, and worse math achievement; for men, those relations were weakly in the opposite direction. Implicit stereotypes had greater predictive validity than explicit stereotypes. Female STEM majors, especially those with a graduate degree, held weaker implicit math=male stereotypes and more positive implicit math attitudes than other women. Implicit measures will be a valuable tool for education research and help account for unexplained variation in the STEM sex gap.
Dads as Teachers: Exploring Duality of Roles in the New Zealand Context
Authors: White Stephanie
Published: June 2011

In the mostly female dominated profession of teaching, this pilot project investigates how a group of males who are both fathers and teachers perceive their experiences as they navigate these dual roles. This qualitative study invited men who were teaching in early childhood, primary and secondary settings in New Zealand, and who were also fathers, to comment on their perceptions of how their dual roles impacted on each other. The themes emerging from their responses included empathy for parents, better understanding of children, benefits for own children, and being viewed as “more real” by their students, as well as being better equipped to understand schools and learning, improved personal and professional qualities, and more time available to spend with family.
Convexity meningiomas: study of recurrence factors with special emphasis on the cleavage plane in a series of 100 consecutive patients
Authors: Alvernia Jorge E. , Dang Nguyen D. , Sindou Marc P.
Published: June 2011

Object

Convexity meningiomas are expected to have a low recurrence rate given their classically “easy resectability.” Nonetheless, recurrence can occur. Factors playing a role in their recurrence are analyzed here, including the extent of resection and tumor histological type, among others, with a special emphasis on the cleavage plane.

Methods

The authors reviewed 100 cases of convexity meningiomas surgically treated between 1987 and 2001 with a median follow-up of 86 months (range 2–16 years). Preoperative and postoperative functional status, Simpson resection grade, histological type, and intraoperative surgical plane with pial vessel invasion were studied and correlated with the recurrence rate.

Results

The average tumor size was 3.6 ± 0.4 cm. The pre- and postoperative Karnofsky Performance Scale scores were 92.6 ± 4.6 and 97.9 ± 2.2, respectively. Ninety-five lesions were benign (WHO Grade I) and 5 were atypical (WHO Grade II). Ninety-one and 9 tumors were subjected to Simpson Grade 1 and 3 resections (three Grade 3a and six Grade 3b), respectively. Surgical deaths did not occur. After a mean follow-up of 7.2 years, 4 meningiomas recurred; 2 (2.2%) after Simpson Grade 1 resections and 2 after Simpson Grade 3 (3a and 3b) resections (22.2%; p = 0.0034). When just the subgroup of Simpson Grade 1/WHO Grade I was studied, the recurrence rate decreased to 1.2% (1 of 86 cases). The recurrence of WHO Grade I tumors was higher in the subpial group than in the extrapial group (p = 0.025). No difference in recurrence according to the cleavage plane was seen in the WHO Grade II subgroup (p = 0.361). As for the subpial group, no difference in recurrence was noted between the WHO Grade I and II subgroups (p = 0.608). Importantly, however, the extrapial subgroup of WHO Grade II lesions had a higher recurrence rate compared with its counterpart in the WHO Grade I subgroup (p = 0.005).

Conclusions

Pial and vascular invasion affect the recurrence rate in convexity meningioma surgery. The recurrence rate of WHO Grade I tumors was higher among those with a subpial plane of dissection than among those with an extrapial one. Histological type did not determine the degree of pial invasion in WHO Grade I and II lesions.
Tracking accuracy of T2- and diffusion-weighted magnetic resonance imaging for infusate distribution by convection-enhanced delivery
Authors: Iyer Rajiv R. , Butman John A. , Walbridge Stuart , Gai Neville D. , Heiss John D. , Lonser Russell R.
Published: June 2011

Object

Because convection-enhanced delivery relies on bulk flow of fluid in the interstitial spaces, MR imaging techniques that detect extracellular fluid and fluid movement may be useful for tracking convective drug distribution. To determine the tracking accuracy of T2-weighted and diffusion-weighted MR imaging sequences, the authors followed convective distribution of radiolabeled compounds using these imaging sequences in nonhuman primates.

Methods

Three nonhuman primates underwent thalamic convective infusions (5 infusions) with 14C-sucrose (MW 342 D) or 14C-dextran (MW 70,000 D) during serial MR imaging (T2- and diffusion-weighted imaging). Imaging, histological, and autoradiographic findings were analyzed.

Results

Real-time T2- and diffusion-weighted imaging clearly demonstrated the region of infusion, and serial images revealed progressive filling of the bilateral thalami during infusion. Imaging analysis for T2- and diffusion-weighted sequences revealed that the tissue volume of distribution (Vd) increased linearly with volume of infusion (Vi; R2 = 0.94, R2 = 0.91). Magnetic resonance imaging analysis demonstrated that the mean ± SD Vd/Vi ratios for T2-weighted (3.6 ± 0.5) and diffusion-weighted (3.3 ± 0.4) imaging were similar (p = 0.5). While 14C-sucrose and 14C-dextran were homogeneously distributed over the infused region, autoradiographic analysis revealed that T2-weighted and diffusion-weighted imaging significantly underestimated the Vd of both 14C-sucrose (mean differences 51.3% and 52.3%, respectively; p = 0.02) and 14C-dextran (mean differences 49.3% and 59.6%; respectively, p = 0.001).

Conclusions

Real-time T2- and diffusion-weighted MR imaging significantly underestimate tissue Vd during convection-enhanced delivery over a wide range of molecular sizes. Application of these imaging modalities may lead to inaccurate estimation of convective drug distribution.
A rare intraosseous arteriovenous malformation of the spine
Authors: Louis Robert G. , Yen Chun Po , Mohila Carrie A. , Mandell James W. , Sheehan Jason
Published: June 2011

The authors report the case of a patient with an intraosseous spinal arteriovenous malformation (AVM) presenting as an epidural mass lesion that was causing spinal cord compression. The 59-year-old woman had bilateral numbness, weakness, and hyperreflexia of both legs. Magnetic resonance imaging revealed intermediate T1 signal and hyperintense T2 signal involving the right transverse process, bilateral pedicles, and T-5 spinous process; the lesion's epidural extension was causing severe canal compromise and cord displacement. Coil embolization was performed, and the patient underwent resection, after which preoperative symptoms improved. Histopathological analysis revealed a benign vascular proliferation consistent with an intraosseous spinal AVM. On review of the literature, the authors found this case to be the second intraosseous spinal AVM, and the first in a patient whose clinical presentation was consistent with that of a mass lesion of the bone.
Oral HPV Infection and Sexuality: A Cross-Sectional Study in Women
Authors: Ragin Camille , Edwards Robert , Larkins-Pettigrew Margaret , Taioli Emanuela , Eckstein Stacy , Thurman Natalie , Bloome Jessica , Markovic Nina
Published: June 2011

Human Papillomavirus (HPV) is the main risk factor for cervical cancers and is associated with close to 36% of oropharyngeal cancers. There is increasing evidence that oral HPV transmission is related to sexual behavior but to our knowledge studies that involve women who have sex with women have not been performed. We examined the prevalence of oral HPV according to sexual behavior among a population-based sample of 118 women and have made some inferences of possible predictors of oral HPV infection. Women were categorized as heterosexual (history of vaginal sex and/or oral sex with males only, n = 75), bisexual (history of vaginal sex and oral sex with females, n = 32) and other (no history of vaginal sex but oral sex with females [homosexuals], virgins and women with incomplete sexual exposure data, n = 11) The prevalence of oral HPV infection was 12/118 (10.2%) for the overall study population and was not significantly different between heterosexual and bisexual women (10.7% (8/75) vs. 12.5% (4/32), p = 0.784). There was no oral HPV detected among homosexual women, virgins or among women where sexual exposure was unknown. Never smokers were more likely to be oral HPV+ compared to former smokers (Adjusted Odds Ratio (Adj OR) = 0.1, 95% CI, 0.0–1.1) and there was no difference in risk between never smokers and current smokers (Adj OR = 0.7, 95% CI, 0.1–4.6). Twenty-five percent (3/12) of oral HPV+ women had a history of HPV and/or genital warts compared to 9% (10/106) of oral HPV-women (p = 0.104). For the women with a history of vaginal sex (n = 110), oral HPV status was statistically significantly different according to oral sex exposure (p = 0.039). A higher proportion of oral HPV-positive women reported that they had no history of oral sex exposure compared to oral HPV-negative women (4/12, 33% vs. 7/98, 8%). The prevalence of cervical HPV infection did not vary between heterosexuals and bisexuals (35.7% (25/70) vs. 35.5% (11/31), p-value 0.411) and for all other women the cervical HPV prevalence was significantly lower (11.1%, 1/9). Our study suggests that smoking and sexual behavior involving males rather than female partners may be possible predictors of oral HPV infection in women. Further studies with larger sample size are needed to confirm these findings.
Absorption and Metabolism of Xanthophylls
Authors: Kotake-Nara Eiichi , Nagao Akihiko
Published: June 2011

Dietary carotenoids, especially xanthophylls, have attracted significant attention because of their characteristic biological activities, including anti-allergic, anti-cancer, and anti-obese actions. Although no less than forty carotenoids are ingested under usual dietary habits, only six carotenoids and their metabolites have been found in human tissues, suggesting selectivity in the intestinal absorption of carotenoids. Recently, facilitated diffusion in addition to simple diffusion has been reported to mediate the intestinal absorption of carotenoids in mammals. The selective absorption of carotenoids may be caused by uptake to the intestinal epithelia by the facilitated diffusion and an unknown excretion to intestinal lumen. It is well known that β-carotene can be metabolized to vitamin A after intestinal absorption of carotenoids, but little is known about the metabolic transformation of non provitamin A xanthophylls. The enzymatic oxidation of the secondary hydroxyl group leading to keto-carotenoids would occur as a common pathway of xanthophyll metabolism in mammals. This paper reviews the absorption and metabolism of xanthophylls by introducing recent advances in this field.
Flavonoids from Praxelis clematidea R.M. King and Robinson Modulate Bacterial Drug Resistance
Authors: Maia Gabriela Lemos de Azevedo , Falcão-Silva Vivyanne dos Santos , Aquino Pedro Gregório Vieira , Araújo-Júnior João Xavier de , Tavares Josean Fechine , Silva Marcelo Sobral da , Rodrigues Luis Cezar , Siqueira-Júnior José Pinto de , Barbosa-Filho José Maria
Published: June 2011

Chemical studies of Praxelis clematidea R.M. King & Robinson resulted in the isolation of six flavones: Apigenine, genkwanine, 7,4’-dimethylapigenin, trimethylapigenin,cirsimaritin and tetramethylscutellarein, which were tested for their toxicity against Staphylococcus aureus SA-1199B, a strain possessing the NorA efflux pump. Efflux pumps are integral proteins of the bacterial membrane and are recognized as one of the main causes of bacterial drug resistance, since they expel antibiotics from the cell. The inhibition of this transporter is one form of modulating bacterial resistance to antimicrobial drugs. The flavones tested did not show any significant antibacterial activity against the Staphylococcus aureus strain used, but were able to modulate bacterial drug resistance. This property might be related to the degree of lipophilicity of the flavones conferred by the methoxyl groups, since 4’,5,6,7 tetramethoxyflavone the most methoxylated compound, reduced the minimal inhibitory concentration of the drug 16-fold.
Simultaneous Second Harmonic Generation of Multiple Wavelength Laser Outputs for Medical Sensing
Authors: Son Seung Nam , Song Jae-Jin , Kang Jin U. , Kim Chang-Seok
Published: June 2011

Multiple wavelength light sources in the medical spectral window region are useful for various medical sensing applications in tissue by distinguishing the absorption and scattering coefficients optically. We propose a simultaneous second harmonic generation of multiple wavelength fiber laser output using parallel channels of periodically-poled lithium niobate (PPLN) waveguides. High intensity dual wavelength lasing output is experimentally realized with two tunable fiber Bragg gratings of 1,547.20 nm and 1,554.48 nm for the efficient conversion to the half wavelengths, 773.60 nm and 777.24 nm, by using two parallel PPLN channels. Compared with a conventional dual second harmonic generation (SHG) configuration based on two different input wavelengths from each independent light source, this method has a relatively higher efficiency to align the input light beam into the adjacent parallel PPLN channels simultaneously. The use of fiber lasers offers several advantages since they are relatively inexpensive, provide high power in excess of tens of watts, are widely tunable, and can produce pulses from milliseconds to femtoseconds.
An Improved Equivalent Simulation Model for CMOS Integrated Hall Plates
Authors: Xu Yue , Pan Hong-Bin
Published: June 2011

An improved equivalent simulation model for a CMOS-integrated Hall plate is described in this paper. Compared with existing models, this model covers voltage dependent non-linear effects, geometrical effects, temperature effects and packaging stress influences, and only includes a small number of physical and technological parameters. In addition, the structure of this model is relatively simple, consisting of a passive network with eight non-linear resistances, four current-controlled voltage sources and four parasitic capacitances. The model has been written in Verilog-A hardware description language and it performed successfully in a Cadence Spectre simulator. The model’s simulation results are in good agreement with the classic experimental results reported in the literature.
Outcomes in the First Year after Initiation of First-Line Haart among Heterosexual Men and Women in the Uk Chic Study
Authors:   UK CHIC Study Steering Committee, Barber Tristan J , Geretti Anna Maria , Anderson Jane , Schwenk Achim , Phillips Andrew N , Bansi Loveleen , Gilson Richard , Hill Teresa , Walsh John , Fisher Martin , Johnson Margaret , Post Frank , Easterbrook Philippa , Gazzard Brian , Palfreeman Adrian , Orkin Chloe , Leen Clifford , Gompels Mark , Dunn David , Delpech Valerie , Pillay Deenan , Sabin Caroline A
Published: June 2011

Background

We analysed the influence of gender on use and outcomes of first-line HAART in a UK cohort.

Methods

Analyses included heterosexuals starting HAART from 1998-2007 with pre-treatment CD4+ T-cell count <350 cells/mm3 and viral load (VL)>500 copies/ml. Virological suppression (<50 copies/ml), virological rebound (>500 copies/ml), CD4+ T-cell counts at 6 and 12 months, clinical events and treatment discontinuation/switch in the first year of HAART were compared using linear, logistic and Cox regression.

Results

Compared with women ( n=2,179), men ( n=1,487) were older and had lower CD4+ T-cell count and higher VL at start of HAART. Median follow-up was 3.8 years (IQR 2.0-6.2). At 6 and 12 months, 72.7% and 75.3% had VL≤50 copies/ml, with no large differences between genders at either time after adjustment for confounders (6 months, OR 0.92 [95% CI 0.76-1.13]; 12 months, OR 1.06 [95% CI 0.85-1.31]). Overall, 79.4% patients achieved virological suppression and 19.2% experienced virological rebound, without gender differences, although men had an increased risk of rebound after excluding pregnant women (adjusted relative hazard [RH] 1.33 [95% CI 1.04–1.71]). Mean CD4+ T-cell count increases at 6 and 12 months were, respectively, 11 2 and 156 cells/mm3 overall, with mean differences between men and women of -14.6 cells/mm3 (95% CI -24.6—4.5) and -12.1 cells/mm3 (95% CI -24.4– 0.2) at 6 and 12 months, respectively. Clinical progression was similar in men and women, but men were less likely to experience treatment discontinuation/switch (adjusted RH 0.72 [95% CI 0.63–0.83]).

Conclusions

Despite higher discontinuation rates among women, men had an increased risk of virological rebound and slightly poorer CD4+ T-cell count responses. Identifying the reasons underlying treatment discontinuation/switch may help optimize treatment strategies for both genders.
Double-Bundle and Double-Tunnel ACL Reconstruction with Looped Proximal Tibial Fixation
Authors: Berumen-Nafarrate Edmundo , Leal-Contreras Carlos
Published: June 2011

Double-bundle anterior cruciate ligament (ACL) reconstruction can be demanding and time consuming and requires twice as many implants, increasing both costs and possible complications. In this article, we present a new approach to double bundle ACL reconstruction: a biological fixation of the tibial side by means of a double tunnel and a U-shape passage of an anterior tibialis allograft, fixed into a double tunnel on the femoral condyle with 2 interference bioabsorbable screws. The technique is designed to combine 2 known procedures for the regular knee surgeon: the mono-tunnel technique and the medial-portal approach.
Assessment of Accuracy of Acetabular Cup Orientation in CT-Free Navigated Total Hip Arthroplasty
Authors: Fukunishi Shigeo , Fukui Tomokazu , Imamura Fumiaki , Nishio Shoji , Shibanuma Nao , Yoshiya Shinichi
Published: June 2011

We have used the Orthopilot (Aesculap AG, Tuttlingen, Germany) computed tomography (CT)-free navigation system to ensure accurate and reproducible acetabular cup orientation. In this system, cup orientation is assessed with respect to bony configuration as determined by palpation of the anatomical landmarks (the bilateral anterosuperior iliac spines and the upper margin of the pubic symphysis). In this study, intraoperative cup orientation as presented by the OrthoPilot navigation system was compared with the value obtained through postoperative radiological assessment using CT Digital Imaging and Communications in Medicine (DICOM) data and Medical Image Processing, Analysis, and Visualization (MIPAV; National Institutes of Health, US Department of Health and Human Services, Bethesda, Maryland). Intra- and postoperative results obtained from 27 consecutive navigated total hip arthroplasties (THAs) were analyzed. For cup positioning, the desired inclination and anteversion angles were set within the “safe zone” proposed by Lewinnek. In the intraoperative evaluation, the mean inclination angle as determined by the navigation system was 43.5° ± 2.17° (range, 39.9° to 46.6°) after the final implantation. In contrast, the mean inclination angle determined by postoperative calculation using MIPAV was 44.9 ± 3.3° (range, 38.1° to 55.0°). A discrepancy of >5° was observed in only 1 hip. For the anteversion, the mean intra- and postoperative values were 11.1° ± 5.6° (range, 0° to 17.8°) and 13.5° ± 5.9° (range, 5.1° to 21.6°), respectively. Again, a discrepancy of >5° was observed in 1 case. Mean differences between the intra- and postoperative values were 1.9° ± 1.9° and 2.6° ± 1.6° for inclination and anteversion, respectively. A good agreement between the intraoperative values presented by the navigation system and those in the postoperative CT evaluation was observed, and the validity of this navigation system was confirmed.
Salzmann’s Nodular Degeneration (Subepithelial Fibrosis)
Authors: Lanier Jeffrey D.
Published: June 2011

Salzmann’s nodular degeneration (subepithelial fibrosis) may cause symptoms of irritation and decreased vision. Removing the subepithelial fibrosis may improve symptoms and vision. In this article, a simple surgical technique to remove the subepithelial fibrosis is described.
A Markov Decision Process for Managing Habitat for Florida Scrub-Jays
Authors: Johnson Fred A. , Breininger David R. , Duncan Brean W. , Nichols James D. , Runge Michael C. , Williams B. Ken
Published: June 2011

Florida scrub-jays Aphelocoma coerulescens are listed as threatened under the Endangered Species Act due to loss and degradation of scrub habitat. This study concerned the development of an optimal strategy for the restoration and management of scrub habitat at Merritt Island National Wildlife Refuge, which contains one of the few remaining large populations of scrub-jays in Florida. There are documented differences in the reproductive and survival rates of scrub-jays among discrete classes of scrub height (<120 cm or “short”; 120–170 cm or “optimal”; >170 cm or “tall”; and a combination of tall and optimal or “mixed”), and our objective was to calculate a state-dependent management strategy that would maximize the long-term growth rate of the resident scrub-jay population. We used aerial imagery with multistate Markov models to estimate annual transition probabilities among the four scrub-height classes under three possible management actions: scrub restoration (mechanical cutting followed by burning), a prescribed burn, or no intervention. A strategy prescribing the optimal management action for management units exhibiting different proportions of scrub-height classes was derived using dynamic programming. Scrub restoration was the optimal management action only in units dominated by mixed and tall scrub, and burning tended to be the optimal action for intermediate levels of short scrub. The optimal action was to do nothing when the amount of short scrub was greater than 30%, because short scrub mostly transitions to optimal height scrub (i.e., that state with the highest demographic success of scrub-jays) in the absence of intervention. Monte Carlo simulation of the optimal policy suggested that some form of management would be required every year. We note, however, that estimates of scrub-height transition probabilities were subject to several sources of uncertainty, and so we explored the management implications of alternative sets of transition probabilities. Generally, our analysis demonstrated the difficulty of managing for a species that requires midsuccessional habitat, and suggests that innovative management tools may be needed to help ensure the persistence of scrub-jays at Merritt Island National Wildlife Refuge. The development of a tailored monitoring program as a component of adaptive management could help reduce uncertainty about controlled and uncontrolled variation in transition probabilities of scrub-height and thus lead to improved decision making.
The Exchange of Emotional Content in Business Communications
Authors: Scott Douglass J. , Coursaris Constantinos K. , Kato Yuuki , Kato Shogo
Published: June 2011

This study compared the exchange of emotional content in PC and mobile e-mail in business-related discussions. Forty American business people were divided into two groups (PC and mobile e-mail users) and were then assigned to anonymous discussion pairs who exchanged a total of six messages on a predetermined topic. When a message was sent, the writers completed two questionnaires related to 12 target emotions: One questionnaire assessed the emotions they experienced and another estimated their partner’s emotional reaction. E-mail readers filled out similar questionnaires. Statistical analysis showed that when emotional exchange was successful, mobile e-mail users more accurately predicted positive emotions than did PC e-mail users. Conversely, when emotional exchange was unsuccessful, mobile e-mail users failed to accurately exchange negative emotions far more than their PC using counterparts. These findings indicate that the communication medium used may influence the exchange of emotional content in text-based communications.
Solar Grade Silicon Materials and Poly-Silicon Solar Cell
Authors: Gao Yong Chao , Zhao Bai Tong , Gao Wen Xiu
Published: June 2011

In this paper, we should analyze the characteristic of the solar grade poly-silicon up-graded by physical process and make comparison with silicon made by Siemens process in wafer and solar cell, also we make a analysis for the degradation of the solar cell module. From the result we find that the silicon block have no obvious drawback such as crack detected by GT infrared and the average minority carrier lifetime is 3.86μs, the minority lifetime and resistivity of the wafer is better than the standard, solar cell prepared using the solar grade silicon wafer by physical process has an average conversion efficiency of 15.78% which is 0.12% higher than the Siemens wafer mainly due to high open circuit voltage. Efficiency degradation of the solar cell made by physical process is less than 3% after half an year which met the international standard. So we come to the conclusion that solar grade silicon prepared by physical process is a promising alternative material for PV industry and become main solar grade poly-silicon in the future.
Application of Rice Husk Charcoal on Remediation of Acid Soil
Authors: Chien Chuan Chi , Huang Ying Pin , Sah Jy Gau , Cheng Wen Jie , Chang Ru Yan , Lu Yueh Shih
Published: June 2011

About 1 million tons of waste rice husk are generated in Taiwan each year. Rice husk has high concentrations of nutrients, such as silicon and potassium. However, it is not decomposed easily because it contains over 70% of cellulose and lignin and hence it is not suitable to be added into soil. In this study, a large quantity of rice husk is carbonized by vertical type continuous carbonization furnace without the presence of oxygen. After it is carbonized, it becomes rice husk charcoal (RHC) and vinegar (RHV). We have found that the addition of RHC carbonized at 600 and 700°C to soil can increase the soil’s concentrations of calcium, magnesium, potassium and silicon as well as its pH value (i.e., lowering its acidity level). Therefore, RHC is a great soil modifier because it can lower the soil’s acidity and increase the soil’s nutrients. According to our experiments, the pH values of the mixtures in different ratios exhibited an increasing and steady of final condition in the 80-day period. The reason was that the CEC (cation exchange capacity) of the mixtures were increased, the specific surface areas of the mixtures increased and the mixtures’ acidity levels were lowered. Therefore, the incorporation of RHC in the soil would benefit the soil on a long-term basis.
Biotribology Behavior of Ultra-High Molecular Weight Polyethylene against Carbon/Carbon Composites Used for Hip Joint Replacement
Authors: Zhang Lei Lei , Li He Jun , Li Ke Zhi , Guo Ling Jun , Cao Wei Feng , Shen Xue Tao
Published: June 2011

In order to investigate the biotribology behavior of a novel artificial joint pair composed of a carbon/carbon composite femoral head and an ultra-high molecular weight polyethylene (UHMWPE) acetabular cup, a hip joint simulator was employed to predict the clinical wear behavior with a constant load and a lubricant of newborn calf serum. The worn surface and the wear particles generated were analyzed by scanning electron microscopy and laser particle size analyzer. The results showed that the worn surface of UHMWPE had a ripple-like morphology with plentiful furrows. The wear particles generated had various morphologies with a size concentrated at about 15 μm.
Degradation Experiments and Modeling of PLGA Blend and Gradient Films
Authors: Liu Hong Ze , Qi Min , Zhu Xing Hua , Wei Zhi Yong
Published: June 2011

PLGA blend and gradient films were designed and prepared to improve the late degradation properties of PLGA films. The gradient films were composed of gradual components of PLGA50/50 and PLGA 75/25, and PLGA 50/50, featuring gradual descents from outside parts to inside parts of the films. Degradation processes of biodegradable PLGA blend and gradient films were also predicted by Monte Carlo simulation to understand the mechanism of degradation. The simulation results indicated that the gradient structure prolonged the mass transfer time of the degradable films, and it induced smoother weight loss than single-component or blend films. The degradation behaviors of single-component, blend and gradient films were experimentally investigated to prove the validity of the models by immersing them into PBS. The experiment indicated that the gradient films have the most stable weight loss curves, which were in well accordance with the simulation by Monte Carlo method.
High Temperature Stability of SiC/Ti Interface
Authors: Ngai Tung Wai Leo , Hu Chang Xu , Zheng Wei , Xie Heng , Li Yuan Yuan
Published: June 2011

Ti, SiC and their composite materials have been widely used as high temperature structural material. The knowledge of interfacial stability between SiC and Ti is vital in high temperature applications. In this study, SiC/Ti diffusion couples were prepared to investigate the interfacial reactions between SiC and Ti at 1273 K. Phase forming sequence, microstructure and thermal stability of SiC/Ti interface were studied. It was indicated that after annealed at 1273 K for 10 days, 4 reaction layers were formed at the SiC/Ti interface. The diffusion path between SiC and Ti is SiC/Ti3SiC2/Ti5Si3/Ti5Si3+TiC/Ti3Si/Ti. As the annealing time prolong, the thicknesses of these reaction layers increased.
Inhibition of Taq DNA Polymerase and DNA Exonuclease ExoIII by an Aqueous Nanoparticle Suspension of a Bis-Methanophosphonate Fullerene
Authors: Kang Feng , Song Gao Guang
Published: June 2011

An aqueous nanoparticle suspension of a bis-methanophosphonate fullerene (n-BMPF) was tested to clarify its effects on polymerase chain reaction (PCR) with the catalyst of Taq DNA polymerase and DNA exonuclease Exo Ⅲ and the template of super-coiled plasmid pEGFP-N1. It was found that the product amounts from PCR decreased significantly with addition of the n-BMPF. The inhibition by the n-BMPF was dose-dependent and IC50 values for reactions of PCR were 2.7 μmol/L. Increase of Taq DNA polymerase amounts in PCR system antagonized the activities of the n-BMPF. However, addition of two scavengers of reactive oxygen species (ROS), mannitol and azide at the concentrations of 2~10 mmol/L did not antagonize the activities of the n-BMPF against PCR. These data implied that this inhibition probably did not correlate to ROS. Meanwhile, the inhibition for the DNA exonuclease Exo Ⅲ by the n-BMPF was evident and dose-dependent.
Efficient Hybrid Infrared Solar Cells Based on P3HT and PbSe Nanocrystal Quantum Dots
Authors: Tan Zha Nao , Zhang Wen Qing , Qian De Ping , Zheng Hua , Xiao Sheng Qiang , Yang Yong Ping , Zhu Ting , Xu Jian
Published: June 2011

The effects of composition on the performance of hybrid photovoltaic cells based on PbSe nanocrystal quantum dot(NQD)/ poly(3-hexylthiophene) nanocomposites were studied. The device performance and the absorption property strongly depended on the loading of PbSe. To improve the device performance, a pure light-absorbing P3HT film was inserted underneath the blended layer of P3HT and PbSe nanocrystal quantum dots in the active region. Such a design allowed for the employment of a thinner bulk heterojunction for more efficient carrier collection without an excessive reduction of the overall light absorption by the photovoltaic cell. The measured device performance showed a significant improvement over previously reported hybrid cells containing bulk heterojunctions of P3HT and Pb(S,Se) nanocrystal quantum dots.
Research of Short-Flow-Route Processes for Magnesium Alloys Prepared by Crystalline Magnesium
Authors: Li Wei Hong , Yang Yuan Sheng , Tian Chang Wen , Tang Shou Qiu , Zhou Ji Xue , Jiang Li Kun
Published: June 2011

Long route and high inclusion content are two common problems existing in the present process for magnesium alloys. To solve these problems, a new process technology, in which the crystalline magnesium is used as the raw material, is developed. The process is melting flux→ adding raw materials in batches → stirring→ holding→ pouring (MASHP). The mechanisms of protection and purification mechanisms are also analyzed. The results show that the MASHP process has high protection and purification effects on magnesium alloys. By the in-batches addition mode of raw materials, no oxidation and evaporation loss of magnesium produce during heating and melting, and the inclusions that self-contained in the crystalline magnesium and that produced by oxidation during heating and melting can be minimized. High quality magnesium alloys can be produced by the new process.
Effects of Microstructural Morphology on Mechanical Properties of Magnesium Alloys
Authors: Li Jing Yuan , Du Xiao Lei
Published: June 2011

The mechanical property of magnesium alloy depends on the alloy elements and microstructure strongly. The multiple dependency relations are studied by investigating magnesium alloys with different Al and Zn contents. The semi-continuous casting billets exhibit quite different microstructural morphologies between the centre and edge of the cross section. The centre shows fine and uniform microstructure while the edge is coarse and reticular. However the difference is almost eliminated when the billets were homogenized at 380°C for 15h. The generation mechanism of casting microstructure is also discussed in this paper. The results show that the morphology of second phase and the size of grain have greater effect on the mechanical properties than the element Zn. The alloys with uniform, fine and non-dendrite microstructure exhibit both high strength and elongation when Al content is about 6% and Zn content is various from 0 to 3%. In contrast, the strength increases and elongation decreases significantly as Al content increases from 0 to 6%.