bluuebunny/crossref_metadata_2025 huggingface dataset:
Biocompatible Hybrid Plasmonic-Magnetic Nanoparticles for Bioimaging
Authors: Sotiriou G.A. , Hirt A.M. , Lozach P-Y. , Teleki A. , Krumeich F. , Pratsinis S.E.
Published: November 2012

Hybrid magnetic/plasmonic nanoparticles possess properties originating from each individual material. Such properties are beneficial for biological applications including bio-imaging, targeted drug delivery, in vivo diagnosis and therapy. Limitations regarding their stability and toxicity, however, challenge their safe use. Here, the one-step flame synthesis of composite SiO2-coated Ag/Fe2O3 nanoparticles is demonstrated. The hermetic SiO2 coating does not influence the morphology, the superparamagnetic properties of the iron oxide particles and the plasmonic optical properties of the silver particles. Therefore, the hybrid SiO2-coated Ag/Fe2O3 nanoparticles exhibit desired properties for their employment in bio-applications.
Solar Spectrum Splitting Parallel Junction High Efficiency Concentrating Photovoltaics
Authors: Broderick Lirong Z. , Stefancich Marco , Roncati Dario , Albert Brian R. , Sheng Xing , Kimerling Lionel C. , Michel Jurgen
Published: November 2012

A compact, single element concentrator comprising a near linear array of prisms has been designed to simultaneously split and concentrate the solar spectrum. Laterally aligned solar cells with different bandgaps are devised to be fabricated on a common Si substrate, with each cell absorbing a different spectral band optimized for highest overall power conversion efficiency. Epitaxial Ge on Si is used as a low cost virtual substrate for III-V materials growth. Assuming no optical loss for the prism concentrator, no shadowing and perfect carrier collection for the solar cells, simulations show that 39% efficiency can be achieved for a parallel four-junction (4PJ) InGaP-GaAs-Si-Ge cell under 200X concentration, and higher efficiency is possible with more junctions.
Multi-Million Fully Atomistic Molecular Dynamics Simulations of Yarn Formation from Carbon Nanotube Forests
Authors: Machado Leonardo D. , Legoas Sergio B. , Galvão Douglas S.
Published: November 2012

In this work we present preliminary results from multi-million fully atomistic classical molecular dynamics simulations carried out to test different existing mechanisms that have been proposed in the literature to explain the drawing of yarns from carbon nanotube forests. Despite the fact that it has been almost ten years since yarns were first drawn, there are still controversies on the mechanisms and necessary conditions that can produce yarns and sheets drawn from carbon nanotube forests. Moreover, few works have tried to understand at atomistic level the details of yarn drawing mechanisms, and no fully atomistic simulations have been carried out so far on this particular subject. Our preliminary results suggest that only direct van der Waals interactions among large bundles seem not to be enough to explain the yarn drawing process. Bundle interconnectors (such as small bundles connecting large bundles) were observed to play a critical role in our simulations. Depending on the topology of these interconnectors it was possible to observe from the simulations fibers/yarn formation from proposed structural models. These models were built based on structural information inferred from scanning electron microscopy data.
Multiscale toughness amplification in natural composites
Authors: Barthelat Francois , Rabiei Reza , Dastjerdi Ahmad Khayer
Published: November 2012

Hard biological materials such as bone and nacre exhibit remarkable mechanical performance, particularly in terms of fracture toughness, despite the weakness of their constituents. Mechanical performance of nacre and bone can largely be explained through their staggered microstructure where stiff inclusions of high aspect ratio are embedded in a softer matrix. The mineral inclusions provide hardness and stiffness while the organic matrix introduces ductility. The high performance of these natural structures is unmatched by any synthetic ceramic, which therefore makes them a substantial source of inspiration for development of new artificial materials. While the modulus and strength of these structures are well understood, fracture toughness remains unclear and controversial. In this work, chevron double cantilever beam fracture tests show that the interfaces in nacre have a low toughness, comparable to that of the tablets (in J terms). This highlights the important role of structural design on fracture toughness. At the next step, a fracture model is presented to explain the toughness amplification observed in natural staggered structures based on two essential extrinsic toughening mechanisms: crack bridging and process zone. The modeling results show that toughness can be further amplified by incorporating high concentrations of small inclusions with high aspect ratio. This conclusion is applicable to construction and optimization of natural and biomimetic composites.
Hierarchical Microstructure and Elastic Properties of Leaf Petiole Tissue in Philodendron melinonii
Authors: Faisal Tanvir R. , Rey Alejandro D. , Pasini Damiano
Published: November 2012

The leaf petiole is an organ that connects the leaf blade to the stem of a plant. From a structural viewpoint, the petiole resembles a cantilever beam that withstands torsional loading due to wind action and bending deformation due to gravity acting on the leaf blade. During growth, the petiole develops defined structural features at multiple length scales, which synergistically determine its mechanical response to external stimuli. The focus of this study is on the hierarchical level (n=3) of the cellular tissue. The goal is to capture the elastic properties of the cellular tissues of the leaf petiole in Philodendron melinonii at that hierarchy. Since the microstructure of the plant tissues resembles a non-periodic cellular pattern, we resort to a 2-D Finite Edge Centroidal Voronoi tessellation (FECVT) to generate a realistic network of polygonal cells. An analysis based on finite element analysis (FEA) is performed to explore the relation between the effective stiffness of Voronoi model and the properties of the cellular tissue. The effective (homogenized) elastic properties of the cellular tissue can be used to calculate the overall flexural and torsional stiffness of the P. melinonii petiole. The FEA of the Voronoi microstructure depicts the anisotropic stiffness properties of the P. melinonii tissue and its dependence with the graded cellularity.
Thin Film Electronic Properties of Ternary Topological Insulator
Authors: Chang Jiwon , Register Leonard F. , Banerjee Sanjay K. , Sahu Bhagawan
Published: November 2012

Using an ab initio density functional theory (DFT), we study thin film electronic properties of topological insulators (TIs) based on ternary compounds of Tl (thallium) and Bi (bismuth). We consider TlBiX2 (X=Se, Te) and Bi2X2Y (X, Y=Se, Te) compounds. Here we discuss the nature of surface states, their locations in the Brillouin Zone (BZ) and their interactions within the bulk region. Our calculations suggest a critical film thickness to maintain the Dirac cone which is smaller than that in binary Bi-based compounds. Atomic relaxations are found to affect the Dirac cone in some of these compounds. We discuss the penetration depth of surface states into the bulk region.
Ferroelectric domain morphology, electrical and electromechanical properties of Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 ceramics
Authors: Tai Cheuk W.
Published: November 2012

Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 ceramics were fabricated by mixed-oxide route. The compositions along morphotropic phase boundary were investigated. Dielectric properties and piezoelectric coefficient were measured. The maximum relative permittivity is 33600 found in the (PIN-PT)x(PMN-PT)1-x ceramics with x = 0.1 at 167 °C. When increasing the amount of Pb(In1/2Nb1/2)O3, the piezoelectric coefficient of the ceramics decreases but the phase transition temperature increases. The selected-area electron diffraction patterns show the pseudo-cubic perovskite symmetry. Diffuse scattering is found in the diffraction pattern taken at higher order zone axis. Transmission electron microscopy study shows that the morphology of ferroelectric/ferroelastic domains is neither tetragonal nor rhombohedral configuration.
Nanostructured biofunctionalized polyurethanes for applications in regenerative medicine
Authors: Kruss Sebastian , Wolfram Tobias
Published: November 2012

Polyurethane (PU) materials are used in a wide variety of implantable devices and technologies, e.g. stents, breast augmentation, nose surgery and bladder reconstruction. Despite the excellent chemical control for manufacturing bulk materials and the good biocompatibility, a major challenge remains interfacing of PU with biological environments. A chemically controlled surface engineering approach could improve desired protein adsorption processes and cellular interactions within different tissues, preventing uncontrolled events of the implant especially in early stages shortly after surgical procedures.

To gain better control over the PU surfaces we polymerized different bulk PU materials and developed a transfer-nanolithography technique to deposit inorganic Au-nanoparticles with defined structural features on the PU surface. Different nanoparticle patterns were transferred and analyzed by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM). Topographical features of PU substrates were investigated by atomic force microscopy (AFM). Transferred Au-nanoparticles showed high stability on PU substrates even under extreme sonication conditions. In a final step, those nanoparticles were functionalized with peptides to facilitate cellular adhesion under physiologically relevant conditions. As proof of concept, rat embryonic fibroblast cells were cultured on a peptide functionalized PU interface and investigated by SEM.

In conclusion, we developed a versatile method to prepare nanostructured and biofunctionalized PUs. These PUs showed good stability characteristics and in vitro biocompatibility in cell culture assays.
Electrospun Fiber - Hydrogel Composites for Nucleus Pulposus Tissue Engineering
Authors: Strange Daniel G. T. , Tonsomboon Khaow , Oyen Michelle L.
Published: November 2012

New materials are needed to replace degenerated intervertebral disc tissue and to provide longer-term solutions for chronic back-pain. Replacement tissue potentially could be engineered by seeding cells into a scaffold that mimics the architecture of natural tissue. Many natural tissues, including the nucleus pulposus (the central region of the intervertebral disc) consist of collagen nanofibers embedded in a gel-like matrix. Recently it was shown that electrospun micro- or nano-fiber structures of considerable thickness can be produced by collecting fibers in an ethanol bath. Here, randomly aligned polycaprolactone electrospun fiber structures up to 50 mm thick are backfilled with alginate hydrogels to form novel composite materials that mimic the fiber-reinforced structure of the nucleus pulposus. The composites are characterized using both indentation and tensile testing. The composites are mechanically robust, exhibiting substantial strain-to-failure. The method presented here provides a way to create large biomimetic scaffolds that more closely mimic the composite structure of natural tissue.
Development of new sol-gel derived Ag-doped biomaterials for dental applications
Authors: Chatzistavrou Xanthippi , Kontonasaki Eleana , Bakopoulou Athina , Theocharidou Anna , Sivropoulou Afroditi , Paraskevopoulos Konstantinos M. , Koidis Petros , Boccaccini Aldo R. , Kasuga Toshihiro
Published: November 2012

The aim of this work was to develop a new Ag-doped bioactive material with antibacterial behavior, optimizing the properties of the new fabricated composite material in the system SiO2 58.6 -P2O5 7.2 -Al2O3 4.2 -CaO 24.9 -Na2O 2.1 -K2O 3 (wt%). Two systems with different concentrations in Ag2O (Ba with 2.1 and Bb with 4.2 wt%) were prepared by the sol-gel method and compared to the respective silver-free control composite (CONTROL). The microstructural characteristics of the developed compositions were characterized by different techniques as UV/VIS spectroscopy, X-ray diffraction analysis (XRD) and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS). The antibacterial properties of the Ag-doped glass-ceramics were tested against the bacterial colony Staphylococcus aureus (S. aureus) which is very characteristic oral bacteria and the material-cell interaction was monitored in a primary culture of Human Gingival Fibroblasts (HGFs). Our study shows the successful incorporation of the silver ions in the ceramic structure and the preparation of new Ag-doped composite materials with cell-proliferation-inductive, as well as antibacterial properties indicating their potential application dental tissue restoration strategies.
Differences in Nanoscale Elasticity of Planar and Nanofibrillar Tissue Cultures
Authors: Tiryaki Volkan Mujdat , Ayres Virginia M. , Ahmed Ijaz , Shreiber David I.
Published: November 2012

Astrocytes are cellular bridges between the neurons and capillaries in the blood brain barrier. It was recently suggested that the nanophysical properties of the basement membrane of the blood brain barrier can influence astrocyte and neuron responses. In this work, cerebral cortical astrocytes were cultured on standard poly-L-Lysine coated glass substrates, Aclar substrates, and electrospun polyamide nanofibers whose properties may recapitulate those of the basement membrane. The nanoscale elasticity of each culture environment was investigated by force curve analysis and compared. The elasticity of the individual nanofibers on nanofibrillar surfaces was also investigated. Finally, variations in elasticity of scaffolds were correlated with astrocyte responses.
Effects of GaN Thin Layer on InGaN at Electrolyte-Semiconductor Interface for the Application of Photoelectrochemical Water Splitting
Authors: Fujii Katsushi , Koike Kayo , Atsumi Mika , Itoh Takashi , Goto Takenari , Yao Takafumi , Sugiyama Masakazu , Nakano Yoshiaki
Published: November 2012

Photoelectrochemical properties of nitride semiconductors are paid attention due to their possibilities of water splitting by visible light absorption. However, the photocurrent density of InxGa1-xN, which absorbs visible light, is usually lower than that of GaN, which has larger band-gap and absorbing only UV light. The reasons of this are thought to be the band-edge position at the semiconductor-electrolyte interface and the crystal quality. The conduction band-edge decreases with increasing of indium composition and across the hydrogen generation energy at around the indium composition of 0.2. This means that the hydrogen generation ability decreases with increasing of indium composition. Low crystal quality is obtained because the lower growth temperature of InxGa1-xN than that of GaN to achieve the indium incorporation. In order to improve the photocurrent density, band-edge energy control and quantum tunneling effect are tried using the structure of thin GaN layer on InxGa1-xN here. The effect for the photocurrent densities is also discussed.
Photophysical Properties of a Nonlinear Dye in PMMA at High Concentration
Authors: Haley Joy E. , Flikkema Jonathan L. , Su Weijie , Krein Douglas M. , Cooper Thomas M.
Published: November 2012

The effects of high concentration on the photophysical properties of a nonlinear material have been of interest for some time in our group. It is well known in the literature that for a nonlinear absorbing dye to be the most effective, high concentrations are needed. The problem is that most photophysical studies in solution are done at low concentration. These low concentration studies are important for understanding inherent materials properties but it is also important to understand what happens in a material at high concentration. In addition to this, efforts have been made to study the effects of incorporating a dye into a solid matrix environment to better understand the constraints this environment has to a given material. Preliminary results for a PMMA system reveal the formation of excimers (excited state dimers) with an increase in concentration. Excimers are forming from the triplet excited state of the E1-BTF. A rate constant for this formation is 2.3 x 106 M-1 s-1. While rather slow, at high concentration the excimer is readily formed. This must be considered when making nonlinear absorption measurements since the excimer will certainly contribute to the overall nonlinearity.
Decrease in Minority Carrier Lifetime of Crystalline Silicon Caused by Rapid Heating
Authors: Sameshima Toshiyuki , Betsuin Kochi , Yoshidomi Shinya
Published: November 2012

Change in the light-induced minority carrier effective lifetime τeff of crystalline silicon caused by rapid laser heating is reported. The top surface of n- and p-type silicon substrates with thicknesses of 520 μm coated with thermally grown SiO2 layers were heated by a 940 nm semiconductor laser for 4 ms. τeff was measured by a method of microwave absorption caused by carriers induced by 620 nm light illumination at 1.5 mW/cm2. τeff for light illumination of the top surfaces was decreased to 1.0x10-5 and 4.8x10-6 s by laser heating at 5.0x104 W/cm2 for n- and ptype 520-μm-thick silicon substrates, respectively. The decrease in τeff resulted from the generation of defect states associated with the carrier recombination velocity at the top surface region, Stop. Laser heating increased Stop to 6000 and 10000 cm/s for n- and p-type silicon samples, respectively. Heat treatment at 400oC for 4h markedly decreased Stop to 21 and 120 cm/s, respectively, for n- and p-type silicon samples heated at 5.0x104 W/cm2. Laser heating at 4.0x104 W/cm2 for 4 ms was also applied to samples treated with Ar plasma irradiation at 50 W for 60 s, which decreased τeff (top) to 2.0x10-5 s and 3.9x10-6 s for n- and p-type silicon samples, respectively. Laser heating successfully increased τeff (top) to 2.8x10-3 and 4.1x10-4 s for n- and p-type samples, respectively. Laser irradiation at 4x104 W/cm2played a role of curing recombination defect sites.
Heterogeneous Integration of a LASER Induced Fluorescence Detection Device for Point-of-Care Microfluidic Biochemical Analysis
Authors: Kamei Toshihiro
Published: November 2012

Fluorescence detection is more advantageous than electrochemical detection in terms of high sensitivity, multiplexed detection capability and isolation from analyte. Integration of fluorescence detection, however, is much more difficult. First, it would require heterogeneous integration of various optical components including an excitation source, an optical filter, a lens, a mirror and a detector. Second, most of integrated fluorescence detectors, even though not fully integrated, suffer from high limit of detection (LOD) compared to conventional optical system that consists of discrete optical components. We have reduced laser light scattering in an integrated hydrogenated amorphous Si (a-Si:H) fluorescence detector, significantly improving a limit-of-detection (LOD). The detection platform comprises a microlens and the annular fluorescence detector where a thick SiO2/Ta2O5 multilayer optical interference filter is monolithically integrated on an a-Si:H pin photodiode. With a microfluidic capillary electrophoresis (CE) device mounted on the platform, the integrated system is demonstrated to separate DNA restriction fragment digests with high speed, high sensitivity and high separation efficiency, implying single molecular DNA detection when combined with polymerase chain reaction (PCR). We are now working towards integration of an excitation source to fabricate heterogeneously integrated laser-induced fluorescence detection (LIF) device that would be comprised of an InGaN laser diode, microlenses and the integrated a-Si:H fluorescence detector.
Strength development of optimised cementitious materials containing fly ashes and silica fume
Authors: Al-Nageim Hassan , Sadique Monower , Atherton William , Seton Linda , Dempster Nicola
Published: November 2012

The objective of this study was to formulate a new cement replacement material using fly ashes. The strength development characteristics of two types of new ternary blended cementitious materials produced from three different types of fly ashes and silica fume (SF) were investigated in this study. The influence of water content, alkali activation synthesis by water dispersing agent on the ternary blends was revealed. The optimised blended mortar containing two different types of fly ashes synthesised with SF was reported to show more compressive strength than the control cement mortar when dispersed with polycarboxylate-based superplasticiser rather than sodium hydroxide (NaOH) activation.
Reliability of the Priebe method for estimating settlements
Authors: Douglas S. Caleb , Schaefer Vernon R.
Published: November 2012

Many estimating methods have been developed for predicting the settlement of stone column reinforced ground. The Priebe method is the most common method used in practice. Even though the Priebe method does not capture all the parameters that affect the performance of stone column reinforced ground, the method is preferred due to its simplicity. An extensive literature search provided data to evaluate the Priebe method. The concept of reliability was incorporated to provide the framework for analysing the prediction method. The Priebe method was found to have an approximately 89% probability that the measured settlement will be smaller than the estimated settlement. The Priebe method was found not always to be conservative, with some possibility of settlement exceeding the estimated amount.
Low Amounts and High Thiol Oxidation of Peroxiredoxins in Spermatozoa From Infertile Men
Authors: Gong Shasha , Gabriel Maria C. San , Zini Armand , Chan Peter , O'Flaherty Cristian
Published: November 2012

Abstract: Seminal oxidative stress occurs when there is an increased production of reactive oxygen species (ROS) and/or a decrease of antioxidant activity, promoting impaired sperm function. Peroxiredoxins (PRDX) are abundant in human semen and are important antioxidant enzymes, which act as ROS scavengers and modulators in ROS‐dependent signaling. Our aim was to determine whether the levels of PRDX1 and PRDX6 and their oxidation on thiol groups are associated with a decrease in sperm motility and DNA integrity. We evaluated the sperm and seminal PRDX level in men (13 healthy controls, 15 men with clinical varicocele, and 17 men with idiopathic infertility). We assessed conventional semen parameters, sperm DNA integrity (by the sperm chromatin structure assay), lipid peroxidation in seminal plasma and spermatozoa (by the thiobarbituric acid reactive substances assay), and the amount and thiol oxidation of PRDX1 and PRDX6 (by immunoblotting). PRDXs were affected in seminal plasma (lower amounts) and in sperm samples (lower amounts and higher levels of thiol oxidation) characterized by lower sperm motility, higher lipid peroxidation, and sperm DNA damage. The thioloxidation ratio of PRDXs (thiol‐oxidized PRDX/total PRDX) correlated negatively with sperm motility (total and progressive) and positively with sperm DNA damage and sperm lipid peroxidation. In conclusion, because of the lower amount of total PRDX1 and PRDX6 and the high thiol oxidation of these PRDXs, very little (less than 20%) protection due to PRDXs remains, and this is associated with impaired sperm function and poor DNA integrity and suggests an important role of PRDXs in the protection of human spermatozoa against oxidative stress.
The High Frequency of Sperm Aneuploidy in Klinefelter Patients and in Nonobstructive Azoospermia Is Due to Meiotic Errors in Euploid Spermatocytes
Authors: Vialard François , Bailly Marc , Bouazzi Habib , Albert Martine , Pont Jean Christophe , Mendes Vanda , Bergere Marianne , Gomes Denise Molina , de Mazancourt Philippe , Selva Jacqueline
Published: November 2012

Abstract: For nonobstructive azoospermic (NOA) patients with a normal karyotype or for Klinefelter syndrome (47,XXY) patients, intracytoplasmic sperm injection is associated with an increased aneuploidy risk in offspring. We examined testicular cells from patients with different azoospermia etiologies to determine the origin of the aneuploid spermatozoa. The incidence of chromosome abnormalities was investigated in all types of azoospermia. Four study subgroups were constituted: Klinefelter patients (group 1), NOA patients with spermatogenesis failure but a normal karyotype (group 2), obstructive azoospermic patients with normal spermatogenesis (group 3), and control patients with normal sperm (group 4). The pachytene stage (in the three azoospermic groups) and postmeiotic cells (in all groups) were analyzed with fluorescence in situ hybridization. No aneuploid pachytene spermatocytes were observed. Postmeiotic aneuploidy rates were higher in the two groups with spermatogenesis failure (5.3% and 4.0% for groups 1 and 2, respectively) than in patients with normal spermatogenesis (0.6% for group 3 and group 4). Whatever the etiology of the azoospermia, the spermatozoa originated from euploid pachytene spermatocytes. These results strengthen the hypothesis whereby sperm aneuploidy in both Klinefelter patients and NOA patients with a normal karyotype results from meiotic abnormalities and not from aneuploid spermatocytes. The fact that sperm aneuploidy was more frequent when spermatogenesis was altered suggests a deleterious testicular environment. The study results also provide arguments for offering preimplantation genetic diagnosis or prenatal diagnosis when a pregnancy occurs for fathers with NOA (whatever the karyotype).
Reactive Oxygen Species and Sperm Function—In Sickness and In Health
Authors: Aitken R. John , Jones Keith T. , Robertson Sarah A.
Published: November 2012

Abstract: The ability of spermatozoa to generate reactive oxygen species (ROS) has been appreciated since the 1940s. It is a universal property of mature spermatozoa from all mammalian species and a major contributor to the oxidative stress responsible for defective sperm function. The mechanisms by which oxidative stress limits the functional competence of mammalian spermatozoa involve the peroxidation of lipids, the induction of oxidative DNA damage, and the formation of protein adducts. ROS production in these cells involves electron leakage from the sperm mitochondria, triggered by a multitude of factors that impede electron flow along the electron transport chain. The net result of mitochondrial ROS generation is to damage these organelles and initiate an intrinsic apoptotic cascade, as a consequence of which spermatozoa lose their motility, DNA integrity, and vitality. This pathway of programmed senescence also results in the exteriorization of phosphatidylserine, which may facilitate the silent phagocytosis of these cells in the aftermath of insemination, in turn influencing the female tract immune response to sperm antigens and future fertility. Despite the vulnerability of sperm to oxidative stress, it is also clear that normal sperm function depends on low levels of ROS generation in order to promote the signal transduction pathways associated with capacitation. Modulators of ROS generation by spermatozoa may therefore have clinical utility in regulating the fertilizing capacity of these cells and preventing the development of antisperm immunity. Achievement of these objectives will require a systematic evaluation of pro‐ and antioxidant strategies in vivo and in vitro.
Free Nerve Ending Density on Skin Extracted by Circumcision and Its Relation to Premature Ejaculation
Authors: Malkoc Ercan , Ates Ferhat , Tekeli Hakan , Kurt Bulent , Turker Turker , Basal Seref
Published: November 2012

Abstract: Many studies have shown that skin tissue extracted by circumcision can cause differences in sexual function, especially at the time of ejaculation. Sensitivity changes in penile skin and sexual satisfaction deriving from circumcision starting from premature ejaculation (PE) are discussed. Furthermore, most of these studies rely on questionnaires. Extracted free nerve endings (FNE) on the foreskin, which can detect temperature, mechanical stimuli (touch, pressure, stretch) or pain (nociception), have not been researched. Our aim is to determine FNEs in foreskin and the affects on sexual function, especially PE. This prospective study was done on adults who voluntarily applied to be circumcised between September 2010 and October 2011. The ejaculation latency times (ELT) before circumcision have been assessed, and a PE diagnostic tool (PEDT) form was filled out by the urologist according to the answers given by the volunteers. The proximal and distal ends of the foreskin were marked before circumcision, and the extracted foreskin was sent to the pathology department to determine FNEs. Twenty volunteers (average age 21.25 ± 0.44 years) were included in the study. The average ELT was 103.55 ± 68.39 seconds, and the average PE score was 4.35 ± 3.13. Proximal, middle, and distal tip nerve densities were compared. Proximal and distal (P / .003) and proximal and middle (P = .011) segments differed from each other, whereas middle and distal were similar (P = .119). There were not any correlations between PEDT scores and total nerve endings number (r = .018, P = .942). Also there were not any correlations between mean ELT and PEDT scores (r = .054, P = .822). The tissue extracted by circumcision has intensive FNEs, yet FNE intensity has no relation to PE.
Sexual Dysfunction Following Radical Prostatectomy
Authors: Benson Cooper R. , Serefoglu Ege Can , Hellstrom Wayne J. G.
Published: November 2012

Abstract: Prostate cancer is the most common solid cancer in men and the second leading cause of cancer death in men. A favored treatment option for organ‐confined prostate cancer in a middle‐aged healthy man is radical prostatectomy (RP). Despite advances in techniques for RP, there remain concerns among physicians and patients alike on its adverse effects on sexual function. Although post‐RP erectile dysfunction has been extensively studied, little attention has been focused on the other domains of sexual function, namely loss of libido, ejaculatory dysfunction, orgasmic dysfunction, penile shortening, and Peyronie disease. The aim of this review is to discuss the most recent literature regarding post‐RP sexual dysfunctions.
Heat generation during plunge stage in friction stir welding
Authors: Veljic Darko , Rakin Marko , Perovic Milenko , Medjo Bojan , Radakovic Zoran , Todorovic Petar , Pavisic Mirko
Published: November 2012

This paper deals with the heat generation in the Al alloy Al2024-T3 plate
under different rotating speeds and plunge speeds during the plunge stage of
friction stir welding (FSW). A three-dimensional finite element model (FEM)
is developed in the commercial code ABAQUS/Explicit using the arbitrary
Lagrangian-Eulerian formulation, the Johnson-Cook material law and Coulomb?s
Law of friction. The heat generation in FSW can be divided into two parts:
frictional heat generated by the tool and heat generated by material
deformation near the pin and the tool shoulder region. Numerical results
obtained in this work indicate a more prominent influence from the
friction-generated heat. The slip rate of the tool relative to the workpiece
material is related to this portion of heat. The material velocity, on the
other hand, is related to the heat generated by plastic deformation.
Increasing the plunging speed of the tool decreases the friction-generated
heat and increases the amount of deformation-generated heat, while increasing
the tool rotating speed has the opposite influence on both heat portions.
Numerical results are compared with the experimental ones, in order to
validate the numerical model, and a good agreement is obtained.
Exergoeconomic optimization of a thermal power plant using particle swarm optimization
Authors: Groniewsky Axel
Published: November 2012

The basic concept in applying numerical optimization methods for power plants
optimization problems is to combine a State of the art search algorithm with
a powerful, power plant simulation program to optimize the energy conversion
system from both economic and thermodynamic viewpoints. Improving the energy
conversion system by optimizing the design and operation and studying
interactions among plant components requires the investigation of a large
number of possible design and operational alternatives. State of the art
search algorithms can assist in the development of cost-effective power plant
concepts. The aim of this paper is to present how nature-inspired swarm
intelligence (especially PSO) can be applied in the field of power plant
optimization and how to find solutions for the problems arising and also to
apply exergoeconomic optimization technics for thermal power plants.
Differences in the bioenergetic potential of athletes participating in team sports
Authors: Malacko Julijan , Doder Dragan , Djurdjevic Slavisa , Savic Biljana , Doder Radoslava
Published: November 2012

Background/Aim. In modern training technology, assessment of aerobic
bioenergetic potential in athletes is commonly performed by standard
laboratory procedures to determine basic or specific functional abilities for
specific sport activity or discipline. The aim of study was to assess the
aerobic bioenergetic potential of athletes participating in basketball,
football and handball. Methods. The study included 87 athletes (29 basketball
players, 29 football players, and 29 handball players) aged 21-24. Evaluation
of the aerobic bioenergetic potential of athletes participating in
basketball, football and handball was performed followed by both univariate
(ANOVA) and multivariate (MANOVA) statistical methods to determine
differences among the athletes in relative (VO2 mL/kg/min) and absolute
oxygen consumption (VO2 L/min). Results. Statistically significant
differences between absolute and relative oxygen consumption were found in
basketball players (Mb), football players (Mf), and handball players (Mh)
(MANOVA, p = 0.00). ANOVA also revealed significant differences in relative
oxygen consumption (VO2 mL/kg/min) (p = 0.00). The football players (55.32
mL/kg/min) had the highest relative oxygen consumption, followed by the
handball players (51.84 mL/kg/min) and basketball players (47.00 mL/kg/min).
The highest absolute oxygen consumption was recorded in the basketball
players (4.47 L/min), followed by the handball players (4.40 L/min) and
footballers (4.16 L/min). Conclusion. Statistically significant differences
in the aerobic bioenergetic potential, expressed by the relative oxygen
consumption were found among atletes participating in different team sports.
It can be assumed that the player from the sports in which it is necessary to
cross greater distance in total during the match have a greater need for
aerobic capacity.
Proton magnetic resonance spectroscopy and apparent diffusion coefficient in evaluation of solid brain lesions
Authors: Ristic-Balos Dragana , Gavrilovic Svetlana , Lavrnic Slobodan , Vasic Brankica , Macvanski Marija , Damjanovic Dusan , Stosic-Opincal Tatjana
Published: November 2012

Background/Aim. Advanced magnetic resonance techniques can provide insight in
physiological changes within pathological canges and contribute to better
distinquishing between different tumor types and their discrimination from
non-neoplastic lesions. The aim of this study was to evaluate the role of
proton magnetic resonance spectroscopy (1H-MRS) and apparent diffusion
coefficients (ADC) in distinguishing intracranial glial tumors from tumor
like nonneoplastic lesions, as well as for differentiating high- from
low-grade gliomas. Methods. This retrospective study included 47 patients
with solid brain lesions (25 nonneoplastic, 14 low-grade and 8 anaplastic
glial tumors). In all patients 1H-MRS (at a TE of 135 ms and 30 ms) and
diffusion- weighted imaging (DWI) were performed. The choline to creatine
(Cho/Cr), choline to N-acetyl aspartate (Cho/NAA), N-acetyl aspartate to
creatine (NAA/Cr) and myoinositol to creatine (mIn/Cr) ratios and the
apparent diffusion coefficient (ADC) were determined. Results. The Cho/Cr
ratio was significantly higher in glial tumors grade II than in
non-neoplastic lesions (p = 0.008) and in glial tumors grade III than in
non-neoplastic lesions (p = 0.001). The Cho/NAA ratio was significantly
higher in glial tumors grade II than in non-neoplastic lesions (p = 0.037).
?ADC/ADC between glial tumors grade II and glial tumors grade III showed a
statistical significance (p = 0.023). Conclusion. Our study showed that
1H-MRS and apparent diffusion coefficients can help in evaluation and
differentiation of solid brain lesions.
Mechanism of Class II correction in prepubertal and postpubertal patients with Twin Force Bite Corrector
Authors: Chhibber Aditya , Upadhyay Madhur , Uribe Flavio , Nanda Ravindra
Published: November 2012

Objective:

To compare the dentoskeletal effects and treatment efficiency of the Twin Force Bite Corrector (TFBC) appliance in Class II correction of patients treated before or after the pubertal growth spurt.

Materials and Methods:

Forty-one normodivergent Class II patients treated with the TFBC appliance were divided into two groups based on their cervical vertebral maturation stage (CVMS). Group 1 (G1) consisted of 23 patients (mean age 12.44 ± 1.59 years) where treatment was initiated before the pubertal growth spurt (CVMS I and II), while group 2 (G2) consisted of 18 patients (mean age 13.76 ± 1.44 years) where treatment was started after the pubertal growth spurt (CVMS III to V). Dentoskeletal measurements were made on lateral cephalograms taken before (T1) and after orthodontic treatment (T2).

Results:

During treatment, G1 had significantly greater skeletal correction than G2, with more dentoalveolar effects being observed in G2 than G1. However, on comparing both groups at the end of treatment (T2) when growth is complete, no differences in the parameters measured were observed. Overall, treatment time was significantly longer for G1 (3.67 ± 1.45 years) compared to G2 (2.75 ± 1.07 years).

Conclusions:

There is no difference in overall dentoskeletal effects obtained at the end of treatment by the TFBC appliance in normodivergent prepubertal vs postpubertal patients. However, treatment efficiency based on treatment timing is significantly greater for the postpubertal group.
Hyperglycemia Slows Embryonic Growth and Suppresses Cell Cycle via Cyclin D1 and p21
Authors: Scott-Drechsel Devon E. , Rugonyi Sandra , Marks Daniel L. , Thornburg Kent L. , Hinds Monica T.
Published: November 2012

In pregnant women, the diabetic condition results in a three- to fivefold increased risk for fetal cardiac malformations as a result of elevated glucose concentrations and the resultant osmotic stress in the developing embryo and fetus. Heart development before septation in the chick embryo was studied under two hyperglycemic conditions. Pulsed hyperglycemia induced by daily administration of glucose during 3 days of development caused daily spikes in plasma glucose concentration. In a second model, sustained hyperglycemia was induced with a single injection of glucose into the yolk on day 0. The sustained model raised the average plasma glucose concentration from 70 mg/dL to 180 mg/dL and led to decreased gene expression of glucose transporter GLUT1. Both models of hyperglycemia reduced embryo size, increased mortality, and delayed development. Within the heart outflow tract, reduced proliferation of myocardial and endocardial cells resulted from the sustained hyperglycemia and hyperosmolarity. The cell cycle inhibitor p21 was significantly increased, whereas cyclin D1, a cell cycle promoter, decreased in sustained hyperglycemia compared with controls. The evidence suggests that hyperglycemia-induced developmental delays are associated with slowed cell cycle progression, leading to reduced cellular proliferation. The suppression of critical developmental steps may underlie the cardiac defects observed during late gestation under hyperglycemic conditions.
Dietary Fat Acutely Increases Glucose Concentrations and Insulin Requirements in Patients With Type 1 Diabetes
Authors: Wolpert Howard A. , Atakov-Castillo Astrid , Smith Stephanie A. , Steil Garry M.
Published: November 2012

OBJECTIVE

Current guidelines for intensive treatment of type 1 diabetes base the mealtime insulin bolus calculation exclusively on carbohydrate counting. There is strong evidence that free fatty acids impair insulin sensitivity. We hypothesized that patients with type 1 diabetes would require more insulin coverage for higher-fat meals than lower-fat meals with identical carbohydrate content.

RESEARCH DESIGN AND METHODS

We used a crossover design comparing two 18-h periods of closed-loop glucose control after high-fat (HF) dinner compared with low-fat (LF) dinner. Each dinner had identical carbohydrate and protein content, but different fat content (60 vs. 10 g).

RESULTS

Seven patients with type 1 diabetes (age, 55 ± 12 years; A1C 7.2 ± 0.8%) successfully completed the protocol. HF dinner required more insulin than LF dinner (12.6 ± 1.9 units vs. 9.0 ± 1.3 units; P = 0.01) and, despite the additional insulin, caused more hyperglycemia (area under the curve >120 mg/dL = 16,967 ± 2,778 vs. 8,350 ± 1,907 mg/dL⋅min; P < 0001). Carbohydrate-to-insulin ratio for HF dinner was significantly lower (9 ± 2 vs. 13 ± 3 g/unit; P = 0.01). There were marked interindividual differences in the effect of dietary fat on insulin requirements (percent increase significantly correlated with daily insulin requirement; R2 = 0.64; P = 0.03).

CONCLUSIONS

This evidence that dietary fat increases glucose levels and insulin requirements highlights the limitations of the current carbohydrate-based approach to bolus dose calculation. These findings point to the need for alternative insulin dosing algorithms for higher-fat meals and suggest that dietary fat intake is an important nutritional consideration for glycemic control in individuals with type 1 diabetes.
Diabetes Screening With Hemoglobin A1c Versus Fasting Plasma Glucose in a Multiethnic Middle-School Cohort
Authors: Buse John B. , Kaufman Francine R. , Linder Barbara , Hirst Kathryn , El ghormli Laure , Willi Steven ,   for the HEALTHY Study Group
Published: November 2012

OBJECTIVE

To characterize middle-school students from the HEALTHY study with glycemic abnormalities, specifically high-risk hemoglobin A1c (A1C) (hrA1C; A1C = 5.7–6.4%) and impaired fasting glucose (IFG; fasting plasma glucose [FPG] = 100–125 mg/dL).

RESEARCH DESIGN AND METHODS

History was collected by self-report, physical measurement was collected by trained study staff, and fasting blood was drawn by trained phlebotomists and analyzed centrally.

RESULTS

At baseline, among 3,980 sixth graders, 128 (3.2%) had hrA1C and 635 (16.0%) had IFG. Compared with A1C <5.7%, hrA1C was associated with non-Hispanic black race/ethnicity, family history of diabetes, and higher measurements of BMI, waist circumference, and fasting insulin. Compared with FPG <100 mg/dL, IFG was associated with Hispanic ethnicity; increased BMI, waist circumference, and fasting insulin; higher frequency of high blood pressure; and higher mean triglycerides. Two years later, children with hrA1C persisted as hrA1C in 59.4%, and one child (0.8%) developed A1C ≥6.5%; children with IFG persisted with IFG in 46.9%, and seven children (1.1%) developed FPG ≥126 mg/dL. Those with hrA1C compared with IFG had a higher BMI in sixth grade, which persisted to eighth grade.

CONCLUSIONS

In the HEALTHY study cohort, hrA1C and IFG define different groups of youth with differentially increased diabetes risk markers. IFG is approximately fivefold more common, but hrA1C is more persistent over time. Optimal screening strategies for diabetes in youth remain unresolved.
Assessing Progress in Retinopathy Outcomes in Type 1 Diabetes
Authors: LeCaire Tamara J. , Palta Mari , Klein Ronald , Klein Barbara E.K. , Cruickshanks Karen J.
Published: November 2012

OBJECTIVE

The Wisconsin Diabetes Registry Study (WDRS) cohort consisted of patients diagnosed with type 1 diabetes in the same geographic region as, but 8–34 years later than the Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR) cohort, providing a unique opportunity to assess changes in complications. We estimated the current prevalence and severity of diabetic retinopathy at 20 years of diabetes duration, compared these between eras, and evaluated the influence of diabetes management.

RESEARCH DESIGN AND METHODS

Twenty-year examinations, including fundus photographs, were completed on 305 WDRS subjects during 2007–2011. A subgroup of the WESDR cohort participated in one of four study visits during 1980–1996, at similar diabetes duration (n = 583). Adjusted ordinal logistic regression with three retinopathy severity categories was used to estimate odds ratios (ORs) of more severe retinopathy with diagnosis during an earlier era.

RESULTS

Mean hemoglobin A1c (HbA1c) was lower in WDRS than in WESDR (8.0% vs. 9.3% [P < 0.001], and 93.4% vs. 21.3% [P < 0.001]) used ≥3 daily insulin injections or an insulin pump. In WDRS, 18% had vision-threatening levels of retinopathy vs. 43% in WESDR. The adjusted OR of more severe retinopathy in the earlier era (OR 3.0 [95% CI 2.2–4.0]) was reduced by including 20-year HbA1c in the model (OR 2.2 [1.6–3.0]).

CONCLUSIONS

Retinopathy severity at a diabetes duration of 20 years is lower in the more recent era of type 1 diabetes. Updated projections should be used when informing newly diagnosed individuals of prognosis and for health care cost assessments. Current glycemic control explained a limited amount of the difference.
Enhanced Absorption of Insulin Aspart as the Result of a Dispersed Injection Strategy Tested in a Randomized Trial in Type 1 Diabetic Patients
Authors: Mader Julia K. , Birngruber Thomas , Korsatko Stefan , Deller Sigrid , Köhler Gerd , Boysen Susanne , Augustin Thomas , Mautner Selma I. , Sinner Frank , Pieber Thomas R. ,   on behalf of the AP@home Consortium
Published: November 2012

OBJECTIVE

We investigated the impact of two different injection strategies on the pharmacokinetics and pharmacodynamics of insulin aspart in vivo in an open-label, two-period crossover study and verified changes in the surface-to-volume ratio ex vivo.

RESEARCH DESIGN AND METHODS

Before the clinical trial, insulin aspart was injected ex vivo into explanted human abdominal skin flaps. The surface-to-volume ratio of the subcutaneous insulin depot was assessed by microfocus computed tomography that compared 1 bolus of 18 IU with 9 dispersed boluses of 2 IU. These two injection strategies were then tested in vivo, in 12 C-peptide–negative type 1 diabetic patients in a euglycemic glucose clamp (glucose target 5.5 ± 1.1 mmol/L) for 8 h after the first insulin administration.

RESULTS

The ex vivo experiment showed a 1.8-fold higher mean surface-to-volume ratio for the dispersed injection strategy. The maximum glucose infusion rates (GIR) were similar for the two strategies (10 ± 4 vs. 9 ± 4; P = 0.5); however, times to reach maximum GIR and 50% and 10% of the maximum GIR were significantly reduced by using the 9 × 2 IU strategy (68 ± 33 vs. 127 ± 93 min; P = 0.01; 38 ± 9 vs. 49 ± 16 min; P < 0.01; 23 ± 6 vs. 30 ± 10 min; P < 0.05). For 9 × 2 IU, the area under the GIR curve was greater during the first 60 min (219 ± 89 vs. 137 ± 75; P < 0.01) and halved until maximum GIR (242 ± 183 vs. 501 ± 396; P < 0.01); however, it was similar across the whole study period (1,361 ± 469 vs. 1,565 ± 527; P = 0.08).

CONCLUSIONS

A dispersed insulin injection strategy enhanced the effect of a fast-acting insulin analog. The increased surface-to-volume ratio of the subcutaneous insulin depot can facilitate insulin absorption into the vascular system.