bluuebunny/crossref_metadata_2025 huggingface dataset:
Aktuelle Entwicklungen bei Verblendmauerwerksabfangungen
Authors: Werner Sven A.
Published: February 2010

Klinkermauerwerk als traditionelles Fassadenelement wird heutzutage in der sog. zweischaligen Bauweise erstellt. Dies ermöglicht eine echte Trennung von Fassade und Tragstruktur, und zusätzlich wird der Einsatz von Dämmmaterial zwischen den zwei Schalen ermöglicht. Diese weit verbreitete Technik ist in Deutschland durch die DIN 1053 geregelt und definiert. Erst seit kurzem gibt es den Bedarf, über die Regelungen der derzeit gültigen DIN 1053‐1:1996‐11 hinaus Lösungen für bautechnische Anforderungen beim zweischaligen Mauerwerk zu finden. Auslöser dafür sind die veränderten Anforderungen an den Wärmebedarf von Gebäuden. Durch die Einführung der EnEV im Jahre 2002 und deren fortlaufende Verschärfung wird immer deutlicher, dass Wärmeverluste über die Fassadenflächen minimiert werden müssen. Dies führt häufig zu Überschreitungen der zulässigen Schalenabstände gemäß DIN 1053, um die geforderten Dämmstärken erreichen zu können. Auch weitere Einflussfaktoren wie z. B. Wärmebrückenverluste durch Abfangkonsolen oder Luftschichtanker rücken stärker in den Fokus. Im Folgenden wird darauf eingegangen, wie Planer und Ingenieure auf die ständig steigenden Anforderungen reagieren können und welche Lösungen die Firma Halfen als Hersteller von Verblendabfangkonstruktionen anbieten kann.

Current Developments for Brickwork Support Systems. Brickwork masonry is a traditional building material for façade constructions and is applied today in a two cavity construction. This enables a strict separation of loadbearing structure and façade elements and thus allows for insulation in between. This common building technique is defined in regulation DIN 1053 for Germany. Recently demands for solutions beyond the above mentioned regulations can be detected. The Main reasons for this are increasing requirements for insulation and focus on energy consumption of buildings. In Germany the EnEV (an Energy Saving Regulation) has come into force in 2002. This regulation specifies that energy loss via façade areas have to be reduced to a minimum and the requirements are increasingly becoming more and more effective with each edition. This leads to increased cavities beyond the specifications of the currently available DIN 1053‐1:1996‐11 mainly due to the required insulation thicknesses. Other influences such as thermal bridges due to brickwork support brackets and brick ties come into focus, too. The following essay will show how designer and engineers can react to the ongoing changes and increasing requirements and which solutions can be provided by company Halfen as a supplier of brickwork support systems.
Sequence‐Selective Organoiridium DNA Bis‐Intercalators with Flexible Dithiaalkane Linker Chains
Authors: Kokoschka Malte , Bangert Jan‐Amadé , Stoll Raphael , Sheldrick William S.
Published: February 2010

The rapid DNA intercalation by dinuclear polypyridyl (η5‐C5Me5)IrIII complexes of the type [{(η5‐C5Me5)Ir(dppz)}2(μ‐L)](CF3SO3)4 1–4 has been studied by UV/Vis spectroscopy, circular dichroism, viscosity measurements and nuclear magnetic resonance. Whereas the Ir atoms of compounds 1–3 are linked by flexible dithiaalkanes of the type L = CH3S(CH2)nSCH3 (n = 4–6), compound 4 contains cyclic 1,4‐dithiane as a shorter more rigid bridging ligand. Stable intercalative binding into CT DNA is indicated for 1–3 by large increases in the DNA thermal denaturation temperature and by induced negative CD bands at about 300 nm. Viscositymeasurements show that the DNA lengthening induced by the bis‐intercalators 1–3 is about twice that caused by the monointercalator 4. An analysis of the NOE cross‐peaks for a 1:1 mixture of 3 with the double‐strand decanucleotide d(5′‐GCGCATCGGC‐3′) demonstrates that 3 intercalates in a sequence‐specific manner from the minor groove between the base pairs C4–G17 and A5–T16, and T6–A15 and C7–G14.
The Nature of the Phosphazene Nitrogen–Metal Bond: DFT Calculations on 2‐(Pyridyloxy)cyclophosphazene Complexes
Authors: Davidson Ross J. , Ainscough Eric W. , Brodie Andrew M. , Harrison John A. , Waterland Mark R.
Published: February 2010

The metal–nitrogen bond in six‐coordinate complexes [ML1Cl]+ (M = Co, Ni, Cu or Zn) of (pyridyloxy)cyclophosphazene, five‐coordinate complexes [ML1Cl2] (M = Cu or Zn) of green‐[NiL1Cl2], and dimetallic complexes [L2(CuCl2)2], [L3(CuCl)2]2+ and [L3(CuCl2)2] [L1 = hexakis(2‐pyridyloxy)cyclotriphosphazene, L2 = hexakis(4‐methyl‐2‐pyridyloxy)cyclotriphosphazene or L3 = octakis(4‐methyl‐2‐pyridyloxy)cyclotetraphosphazene] of red‐[NiL1Cl2], has been investigated by using density functional theory (DFT) and natural bond order (NBO) analysis. The calculations show that the divalent metal ions bind to the phosphazene ring nitrogen by a σ‐type bond and that the lengthening of the PN bonds, which flank the metal coordination site, can be explained as a result of electron density that is transferred from PN bonding orbitals to the 4s orbital of the metal ion rather than a decrease in the π component of the bond as suggested by earlier models. It can be assumed that this explanation of the bonding is valid for the wide range of metallo‐phosphazene complexes and that metal ions will bind to the PN backbone of polyphosphazenes in a similar manner.
Organocatalytic Enantioselective aza‐Michael Additions of N‐Heterocycles to α,β‐Unsaturated Enones
Authors: Lv Jian , Wu Hao , Wang Yongmei
Published: February 2010

A procedure for enantioselective organocatalytic conjugate additions of a variety of N‐heterocycles to α,β‐unsaturated enone systems is presented. The reactions are efficiently catalyzed by salts of 9‐amino‐9‐deoxy‐epiquinine (3d). Cyclic, acyclic, and aromatic enones can be used in reactions with 1H‐benzotriazole (1a) or 5‐phenyltetrazole derivatives 12, providing the Michael addition products in high yields and with good to excellent enantioselectivities.
Generation of Indole Alkaloids in the Human‐Pathogenic Fungus Exophiala dermatitidis
Authors: Kindler Bernhard L. J. , Krämer Hans‐Joachim , Nies Silke , Gradicsky Philipp , Haase Gerhard , Mayser Peter , Spiteller Michael , Spiteller Peter
Published: February 2010

Exophialin, a previously unknown indole alkaloid, was isolated from the human‐pathogenic fungus Exophiala dermatitidis upon cultivation on a medium containing tryptophan as sole nitrogen source. Its structure has been elucidated by 1D and 2D NMR experiments and mass spectrometry. When the mutant strain Mel‐1 was used in place of the wild‐type strain, the new indole alkaloid 8‐hydroxyexophialin was generated instead of exophialin. This result indicates that the aromatic moiety of exophialin originates from 2‐hydroxyjuglone, a shunt product of the 1,8‐dihydroxynaphthalene melanin biosynthesis, which is only produced by the wild‐type strain,but not by the mutant. In contrast, the mutant accumulatesflavioline, which acts as precursor leading to the generation of 8‐hydroxyexophialin instead of exophialin.
Dose‐dependent effect of EGF on migration and differentiation of adult subventricular zone astrocytes
Authors: Gonzalez‐Perez Oscar , Quiñones‐Hinojosa Alfredo
Published: February 2010

Adult neural stem cells (NSCs) are located in the subventricular zone (SVZ), a specialized brain niche located on the walls of the lateral ventricle. Under physiological conditions, NSCs generate a large number of young neurons and some oligodendrocytes, however the mechanisms controlling cell proliferation and migration are unclear. In vitro, epidermal growth factor (EGF) signaling has been shown to be an important mediator of cell proliferation and migration in the adult brain; however, the primary SVZ progenitors that respond to EGF are not well known. In this study, we isolated SVZ type‐B astrocytes and cultured them under different EGF concentrations. We found a dose‐dependent effect of EGF on proliferation rates and migration of SVZ type‐B astrocytes. We found that GFAP+ type‐B astrocytes gave rise to highly migratory and proliferating cells that expressed Olig2 and NG2. After EGF withdrawal, a significant number of EGF‐stimulated cells differentiated into S100β+/O4+ oligodendrocytes. This study provides new insights about the production of oligodendrocytes derived from the astrocyte NSCs residing in the adult SVZ. To be able to manipulate the endogenous adult progenitors, it is crucial to identify and isolate the responding primary precursors and determine the extracellular signals that regulate their cell division, migration, and fate. © 2010 Wiley‐Liss, Inc.
Journal of Bone and Mineral Research
Authors: Harrison J. E. , Hitchman A. J. W. , Hitchman A. , Holtrop M. E.
Published: February 2010

The effects of fluoride (F) on ectopic bone formation induced in rats by implants of demineralized cortical bone tissue were studied. Test rats received sodium fluoride (NaF), 6 mmol/liter in drinking water, and controls received fluoride-free water. Implant accumulations of tracer hydroxyproline ([3H](OH)P), 45Ca, and stable Ca were determined 24 h after injections of tritiated proline ([3H]P) and 45Ca, to estimate rates of collagen synthesis, mineralization, and net mineral mass, respectively. Conventional histology on undemineralized implant sections was done. Mineralized bone was first observed by implant histology, 2 weeks after implantation and continued to increase up to 8 weeks. A few chondrocytes were observed. Prior to bone formation, dense fibrous tissue was observed within the marrow space of the original implant. The rate of collagen synthesis peaked at 1 week, again at 3 weeks, and then continued at a slower rate up to 8 weeks. The rates of mineralization paralleled the rates of collagen synthesis between 2 and 8 weeks, indicating bone mineralization over this period. During the first 2 weeks after implantation no mineral deposition was observed. The initial peak of collagen synthesis without mineralization (0-2 weeks) indicates fibrous tissue formation and is in agreement with the histological analysis. Fluoride treatment increased rates of collagen synthesis during both the initial period of fibrous tissue formation and later bone formation. The ratio of mineralization rate to collagen synthesis rate (45Ca/[3H](OH)P) was decreased by fluoride throughout the 2-8 week period, but net mineral mass was comparable to control rats by 8 weeks, indicating that fluoride delays, but does not prevent, bone mineralization. Fluoride stimulation of both fibrous tissue and bone suggests effects on precursor cells, possibly cells of the immune system.
Journal of Bone and Mineral Research
Authors: DR. Bang S. , Baud C. A.
Published: February 2010

The electron microorobe was used to display the topographical distribution pattern of fluoride (F) at the microscopical level in the iliac bone of an osteoporotic patient treated with fluoride. Composite x-ray image of F Kα emission revealed a high concentration of fluoride in the periosteal and endosteal bone layers, in the cancellous bone, and in certain osteons, which corresponded to the bone formed during the period of fluoride treatment. Fluoride was also concentrated around the Haversian canals in the vicinity of the capillary blood vessels by a diffusion process. Morphometric analysis showed that more cancellous bone than cortical bone is formed.
Journal of Bone and Mineral Research
Authors: DR. Delmas P. D. , Dupuis J. , Duboeuf F. , Chapuy M. C. , Meunier P. J.
Published: February 2010

Eighty one women with vertebral osteoporosis were treated for up to 2 years with fluoride administered either as monofluorophosphate (MFP, 200 mg/day, i.e., 26.4 mg fluoride-ion) or sodium fluoride (NaF, 50 mg/day, i.e., 22.6 mg fluoride-ion). All patients received calcium supplementation (1 g of Ca2+/day) taken apart from NaF and in the same tablet for MFP. Despite almost similar fluoride dosage of both regimens, the early increase in the bone mineral density (BMD) of the lumbar spine was higher with MFP than with NaF, reaching 11% and 4%, respectively, at 1 year (p = 0.007), and 21% and 6%, respectively, at 18 months (p < 0.001). The incidence of lower extremity pain syndrome related to benign stress microfactures was also higher with MFP than with NaF (35% and 15%, respectively, p < 0.01). Urinary fluoride levels were higher in the MFP than in the NaF group (9.6 ± 3.5 vs. 6.8 ± 3.4 at one year, p = 0.003), suggesting that this difference in efficacy and tolerance is related to a better bioavailability of fluoride provided by MFP than by NaF. The occurrence of a stress microfracture could not be predicted by any clinical, biochemical, or densitometric parameter before treatment, but patients presenting with a stress microfracture during the course of the treatment had a higher gain in bone mass than those without stress fractures (at 1 yr+11 vs. +5%, p = 0.03 and at 18 months +18 vs. +6.9%, p < 0.02). In conclusion, there is a clear correlation between the efficacy and the occurrence of side effects of fluoride therapy in osteoporosis. In addition to the dose, the bioavailability of the fluoride salt may play a critical role in the magnitude of the response and should be taken into account when establishing the optimum therapeutic dose, as the therapeutic window may be narrow.
Journal of Bone and Mineral Research
Authors: Pak Charles Y. C. , Sakhaee Khashayar , Zerwekh Joseph E.
Published: February 2010

Long-term clinical effects of intermittent sodium fluoride (slow-release) therapy were assessed in 71 patients with primary osteoporosis. In Group I (receiving 1,25-(OH)2D3 2 μg/day for 2 weeks before 3 months of sodium fluoride treatment 25 mg twice a day, in each 5-month cycle), vertebral (L2-L4) bone mineral content did not change significantly. However, the L2-L4 bone mineral content significantly increased by 3.1% in Group II (those who did not receive 1,25-(OH)2D3 during 5-month cycle), 3.5% per patient year in Group III (combined NaF 25 mg twice a day with 1,25-(OH)2D3 0.5 μg/day for 12 months in each 13-month cycle), and by 7.8% per patient year in Group IV (combined NaF with calcium citrate for 12 months in each 13-month cycle). The rise in vertebral bone mineral content was sustained, with an annual increment of 4.2% during the third year compared with 4.4% during the first year. The vertebral fracture rate declined significantly from the pretreatment value in all groups, but comparison with a placebo control group was not available. There was no significant change in the bone density of the radial shaft or of the proximal femur. The rate of hip fracture (nontraumatic) during treatment was 1.8% per patient year, the same as before treatment. The drug was well tolerated with only minor infrequent gastrointestinal and rheumatic side effects. Thus, intermittent slow-release sodium fluoride treatment with adequate calcium supplementation augments spinal bone mass and apparently inhibits vertebral fractures, with a satisfactory safety of usage; however, it has no effect on appendicular bone mass or on hip fracture rate. The vertebral fracture rate declined significantly in all groups, suggesting that fluoride may reduce vertebral fractures. However, comparison with a placebo control group was not available.
Journal of Bone and Mineral Research
Authors: Schulz E. E. , Flowers C. , Sauser D. D. , Brin B. N. , Wergedal J. E. , Baylink D. J.
Published: February 2010

We previously described new bone formation in fluoride-treated osteoporotic patients. Since then, several investigators have contended that fluoride-induced “hot spots,” as seen on bone scintigrams, represent stress fractures. To further evaluate this issue we analyzed scintigrams, radiographs, and quantitative computer tomography (CT) scans of the spine and femoral condyles from 129 patients, obtained before and during therapy. Hot spots, new or of increased intensity, were more than twice as common in the weight-bearing peripheral skeleton than in nonweight-bearing sites (p < 0.001). The hot spots were usually diffuse, multiple, bilateral, and mostly seen early in therapy, a pattern quite different from that expected of stress fractures. Previously, we postulated that mechanical stress and fluoride act synergistically to stimulate new bone formation. If this hypothesis were correct, we would expect to see a greater increase in femoral condyle bone density in patients with hot spots. Consistent with this hypothesis, patients who developed hot spots in the knees had a greater increase in condylar density (22 ± 2.5 vs. 9 ± 3.3 mg/cc) than those without hot spots and stress fractures were not seen in either group. Additionally, patients with more than 5 hot spots in the peripheral skeleton had greater increases in spinal and condylar density than those with fewer than 5 hot spots. Finally, stress fractures were found in less than 2% of our patients. While we do not exclude the possibility that some additional patients may have had stress fractures, our data support the hypothesis that the great majority of hot spots seen on the scintigrams are the sites of new bone formation.
Journal of Bone and Mineral Research
Authors: Dr. Gutteridge Donald H. , Price Roger I. , Kent G. Neil , Prince Richard L. , Michell Patricia A.
Published: February 2010

Spontaneous fractures were reported to be rare (<1%) in 1664 hospital admissions for hip fracture in the 1950s in Sweden. We report 11 fluoride-treated postmenopausal patients who developed spontaneous fractures of the femoral necks, all subcapital initially. In 7 patients who continued treatment there were later femoral neck or shaft fractures; in 6, these were bilateral (one followed a fall). In all there were 19 spontaneous fractures: 5 were asymptomatic, including 2 with deformity; 12 fractures required surgery. Five were incomplete (stress) fractures. All were treated with supplementary calcium 1 g daily; 10 had vitamin D supplementation. In all patients where the timing was known, the initial and subsequent fractures were preceded by, or associated with increased bone turnover as measured by plasma alkaline phosphatase (pAIP) (i.e., they were all “good responders”). Two had pretreatment hip fractures following falls. We compared these 11 (Group 1) and another identically treated group of 14 patients (Group 2), without spontaneous femoral fractures and not different in mean age, pretreatment vertebral fractures, years since menopause, fluoride dosage, and plasma creatinine. Group 1 had a lower (p < 0.05) index of cortical bone in the femoral neck, as assessed by the ratio “calcar width/femoral neck minimum width.” The 6 biopsied fluorotic patients from Group 1 had a higher (p < 0.05) bone fluoride content than the 4 biopsied fluorotic patients from Group 2. Furthermore, histological cortical features of thinning, increased porosity, and advanced tunneling resorption characterized Group 1 posttreatment biopsies. There were no significant differences in peak pAIP responses in the two groups. Mild asymptomatic vitamin D excess may have been a contributing factor in three Group 1 patients.

Two further treatment groups have been studied more recently by forearm single-photon absorptiometry (SPA) at two sites; a cyclic NaF group (Group 3) and a calcium ± vitamin D group (Group 4). Neither showed significant changes in forearm cortical bone density on treatment for 2 and 1.5 years, respectively, but Group 3 showed a significant increase in density at an ultradistal (60% trabecular) site. The pAIP response in Group 3 was significantly less than in Group 1. Spontaneous femoral neck or shaft fractures did not occur in either Groups 3 or 4. Therefore, we recommend: (1) Avoidance of sodium fluoride (NaF) treatment if pretreatment femoral fracture or thin femoral neck cortices exist. (2) Reduction in NaF dosage if pAIP or osteocalcin increases by over 50% of pretreatment values. (3) Cessation of NaF if femoral neck or shaft fracture occurs during treatment, and also on the attainment of early to moderate spinal fluorosis. (4) Consideration of cyclic NaF treatment, to limit overstimulation of bone turnover and to enhance mineralization.
Journal of Bone and Mineral Research
Authors: DR. Bayley T. A. , Harrison J. E. , Murray T. M. , Josse R. G. , Sturtridge W. , Pritzker K. P. H. , Strauss A. , Vieth R. , Goodwin S.
Published: February 2010

The possible effects of fluoride in inducing fractures were studied in 61 patients treated with sodium fluoride (NaF), 40–60 mg daily in combination with calcium and vitamin D. Nine patients developed the fluoride-(F) related lower extremity pain syndrome. Four other patients had stress fractures associated with trauma. Seven of the 61 patients had 10 upper femur fractures of which 5 were stress fractures. The bone mineral mass of the central skeleton including the hips was measured by neutron activation and the results expressed as a calcium bone index (CaBI) which normalizes the results to that of young adults of the same body size (normal range 0.75–1.2). At the time of hip fracture, 4 patients with a minimal increase in bone mass (mean ΔCaBI 0.01) had 4 femur fractures and 3 patients with a marked increase (mean ΔCaBI 0.24) had 6. The 7 patients with upper femur fractures at 4 years had a significantly higher bone fluoride retention, 30 mg/g Ca compared with 23.9 mg/g Ca for the other 54 (p < 0.02) and were older, 73.1 versus 64.2 years (p < 0.01). Using all 61 fluoride-treated patients, femur fractures/patient were significantly correlated to bone fluoride (p < 0.05) and to age (p < 0.05). By partial correlation, only the correlation between hip fractures/patient and bone fluoride remained significant after controlling for the effect of age (p < 0.05). These results suggest that fluoride therapy may be implicated in the pathogenesis of hip fractures which may occur in treated patients despite a rapid, marked increase in bone mass. The lower extremity pain syndrome is not frequently associated with stress fractures in this study.
Journal of Bone and Mineral Research
Authors: Duursma S. A. , Raymakers J. A. , De Raadt M. E. , Karsdorp N. J. G. H. , Van Dijk A. , Glerum J.
Published: February 2010

The aim of the study was to investigate the usefulness of urinary fluoride excretion in evaluating fluoride therapy. In a prospective study, 35 patients with osteoporosis were treated for about 44 months with a mean dosage of 31.4 mg fluoride ion per day. Urinary fluoride excretion and serum alkaline phosphatase activity were measured at 3-month intervals. Bone mineral content (BMC) was measured in L2–L4 with dual-photon absorptiometer. The mean number of BMC measurements was 5.7 per patient. The interindividual reproducibility for measurements in 10 patients was 2.1%. For each individual, the regression coefficient of BMC for the period of treatment was calculated. Responders were defined as those who had a positive value and nonresponders had 0 or a negative value. The percentage responders was 83%. Between responders and nonresponders no differences were found for age, fluoride dosage, duration of treatment, or changes in serum alkaline phosphatase activity. Urinary fluoride excretion was higher in responders than in nonresponders (p < 0.001) and a positive correlation (p < 0.001) was obtained between the changes in BMC and urinary fluoride excretion. In the responders, 90% had a urinary fluoride excretion > 8 mg/24 h. All nonresponders had a urinary fluoride excretion < 8 mg/24 h. Urinary fluoride excretion is a valuable predictor of BMC response during fluoride therapy for osteoporosis.
Journal of Bone and Mineral Research
Authors: Wiers Brandon H. , Francis Marion D. , Hovancik Kristine , Ritchie Candace K. , Baylink David J.
Published: February 2010

In this study we investigated the possibility of the formation of a calcium fluoride surface film on the new bone matrix in patients undergoing fluoride treatment for osteoporosis. This calcium fluoride film could interfere with the normal mineralization process and lead to hyperosteoidosis (osteomalacia), a well-documented complication seen in fluoride-treated patients. During treatment, fluoride circulating in the blood and extracellular fluid of patients, could interact with the components of the serum, but particularly calcium and magnesium ions. The interrelationships among serum components in the presence of fluoride ion may result, at thermodynamic equilibrium, in deposition on the apatitic bone surface of phases such as calcium fluoride, fluorapatite, or fluorhydroxyapatite. Differences in the phase deposited among patients could result in differences in response to fluoride treatment. A computer program based on equilibrium thermodynamic data was utilized to study the physicochemical calcium, fluoride, and phosphate interrelationships in serum. In all the computer calculations, fluorhydroxyapatite (FHAP), alone or in combination with hydroxyapatite (HAP), was determined to be the thermodynamically stable precipitating surface phase. These data strongly suggest that calcium fluoride surface film is not the reason for the delay of mineralization of fluoride-stimulated new bone. Based on these calculations, we now advance the hypothesis that the effect of fluoride to cause osteomalacia is due to an effect on osteoblasts and also on osteocytes. Consistent with this hypothesis was the finding in bone biopsies, that the excess of osteoid in fluoride-treated patients was found not only at the mineralization front (which is transversed by osteoblast cell processes), but also around young osteocytes, two sites where FHAP or FAP is presumed to be formed. It is possible that an adsorption/desorption of the FHAP phase occurring at the osteoblastic canalicular and osteocytic lacunar surface leads to prolonged fluoride exposure of osteoblast processes in canaliculi and of young osteocytes to fluoride thereby disrupting the normal process of mineralization. The delay in mineralization (osteoid accumulation) may be further accentuated by acid equilibrium processes which occur during mineral deposition and which would enhance cellular fluoride uptake at the calcifying front and at the periphery of the osteocyte.
Journal of Bone and Mineral Research
Authors: Taylor M. L. , Maconnachie E. , Frank K. , Boyde A. , DR. Jones S. J.
Published: February 2010

Osteoclasts were isolated mechanically from bones of prehatch chicks and cultured on dentine for 24 or 39 h in medium without or with added sodium fluoride at concentrations of 0.15, 1, 15, or 30 mg/liter. Fixed and toluidine blue-stained specimens were examined by light microscopy and osteoclasts were counted, all cells were removed and resorption pits were counted. The dentine was then prepared for scanning electron microscopy (SEM) and pits located on a raster search using backscattered electron imaging. Stereophotogrammetric measurements were made of the depths, plan and true surface areas and volumes of pits, and the volume: area ratio and a three-dimensional form factor calculated for each. The presence or absence of a ring of demineralization around each pit was recorded. Pits with the same plan area were significantly (p < 0.001) less deep in cultures containing 15 or 30 mg/liter NaF and the incidence of rings around pits was higher (controls 2.7%, 15 mg/liter 313%, 30 mg/liter NaF 39.7%). In one experiment, pits were larger in the specimen cultured with added 1 mg/liter NaF, but in a much larger series of 631 (251 in the control and 380 in the 1 mg/liter NaF cultures) pits measured, depths, volumes and volume:plan-area ratios were significantly lower (p < 0.001), and rings round pits 2.5 times more common, in the fluoride-treated group. A complex interplay of stimulation of some cells in the culture with indirect stimulation of osteoclasts and direct inhibition of osteoclastic resorptive function may be operating at this concentration of fluoride. In vivo, therapeutic doses of sodium fluoride would be expected to act not only to increase the formation of osteoid but also to suppress osteoclastic activity.
Journal of Bone and Mineral Research
Authors: Orcel PH. , De Vernejoul M. C. , Miravet L. , Kuntz D. , Prier A. , Kaplan G.
Published: February 2010

We report clinical and bone morphometric findings in 18 osteoporotic patients who experienced stress fractures during fluoride therapy. Patients were treated with either sodium fluoride (n = 15), or sodium monofluorophosphate (n = 3). Oral calcium supplementation was given in 11 patients, and vitamin D in 13. Stress fractures occurred after 17.1 ± 10.3 months of therapy (range: 5–41 months). Atraumatic sudden pain in a lower limb bone extremity, normal initial roentgenogram, high 99technetium uptake on early bone scan, and a 3 to 4 week delay in linear bone condensation area at the same site were characteristics of stress fracture. The most frequent sites were the tibial metaphysis (n = 13), femoral neck (n = 10), and calcaneus (n = 4). Biochemical data showed increased plasma alkaline phosphatase levels in 11 patients, and mild renal failure in 2. Bone histomorphometry was performed on an iliac crest specimen in 10 patients at the time of the stress fracture. Trabecular bone volume was normal, and formation parameters were increased. Features of osteomalacia were encountered in only 2 patients with decreased renal function. Trabecular resorption was increased, as assessed by the osteoclastic surface (1.01 ± 1.15% bone surface), and the number of osteoclasts (0.44 ± 0.49 per mm2 bone section). The clinical course was favorable in all patients who stopped fluoride, although 5 patients who continued the treatment had either completion of femoral neck stress fractures to hip fractures (n = 2), or recurrent stress fractures (n = 2), or both (n = 1). Fluoride appears to be a key factor in the pathogenesis of stress fractures, and may be associated with increased trabecular resorption in some treated patients.
Robot‐assisted fracture reduction using three‐dimensional intraoperative fracture visualization: An experimental study on human cadaver femora
Authors: Oszwald Markus , Westphal Ralf , Bredow Jan , Calafi Afshin , Hufner Tobias , Wahl Friedrich , Krettek Christian , Gosling Thomas
Published: February 2010

Closed fracture reduction can be a challenging task. Robot‐assisted reduction of the femur is a newly developed technique that could minimize potential complications and pitfalls associated with fracture reduction and fixation. We conducted an experimental study using 11 human cadaver femora with intact soft tissues. We compared robot‐assisted fracture reduction using 3D visualization with manual reduction, using 2D fluoroscopy. The main outcome measure was the accuracy of reduction. The manual reductions were done by an experienced orthopedic trauma surgeon, whereas the robot‐assisted reductions were done by surgeons of different experience. The robot‐assisted group showed significantly less postreduction malalignment (p < 0.05) for internal/external rotation (2.9° vs. 8.4°) and for varus/valgus alignment (1.1° vs. 2.5°). However, the reduction time was significantly (p < 0.01) longer (6:14 min vs. 2:16 min). The higher precision associated with robot‐assisted fracture reduction makes this technique attractive and further research and development worthwhile. In particular, less experienced surgeons may benefit from this new technique. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:1240–1244, 2010
Holocene palaeoceanographic changes in Barrow Strait, Canadian Arctic: foraminiferal evidence
Authors: Gregory Thomas R. , Smart Christopher W. , Hart Malcolm B. , Massé Guillaume , Vare Lindsay L. , Belt Simon T.
Published: February 2010

Holocene changes in the benthic and planktic foraminiferal fauna (>63 µm) from a marine sediment core (ARC‐3 Canadian Arctic Archipelago, 74° 16.050′ N, 91° 06.380′ W, water depth 347 m) show that significant environmental and palaeoceanographic variations occurred during the last 10 ka. Foraminiferal assemblages are restricted to the ca. 4.5–10 ka interval as younger samples are mostly barren of foraminifera due to intense carbonate dissolution after ca. 4.5 ka. Foraminiferal assemblages in the ca. 4.5–10 ka interval are dominated by the benthic species Islandiella helenae and Cassidulina reniforme (57% of total), with Elphidium clavatum, Cibicides lobatulus and Buccella frigida also being common in this interval. The dominance of these species indicates a seasonal sea ice regime which is consistent with the occurrence of the sea ice diatom‐derived organic geochemical biomarker IP25 throughout the core. The abundances of C. reniforme and E. clavatum decline upcore; consistent with more frequent mixing of the Barrow Strait water column during the early Holocene. It is likely that the influence of CO2‐rich Arctic surface water masses have caused an increase in bottom water corrosivity after ca. 8.5 ka, and dissolution has been further enhanced by sea ice‐related processes after ca. 6 ka, concomitant with increased IP25 fluxes. Dissolution is strongest when IP25 fluxes are highest, suggesting a link between the sea ice and benthic systems. Copyright © 2010 John Wiley & Sons, Ltd.
Surface‐enhanced Raman spectroscopy for quantitative measurement of lactic acid at physiological concentration in human serum
Authors: Hsu Po‐Hsiang , Chiang Huihua Kenny
Published: February 2010

Lactic acid is a simple and effective indicator for estimating physiological function. Rapid and sensitive detection of lactic acid is very useful in clinical diagnosis. However, the concentration of lactic acid in the physiological state is too low to be detected using traditional Raman spectroscopy. We applied silver colloidal nanoparticles‐mediated surface‐enhanced Raman spectroscopy (SERS) for rapid identification and quantification of lactic acid. The standard SERS spectra of lactic acid were defined and the 1395 cm−1 band intensity was used for quantification from 0.3 to 2 mM (R2 = 0.99). In clinical blood sample measurement, the ultrafiltration (cutoff value 5 kDa) can efficiently reduce background fluorescence to improve SERS performance. We established identical and optimal procedure by adjusting reaction time and volume ratio of serum and nanoparticles to obtain high SERS reproducibility. Finally, we showed that silver colloidal nanoparticles‐mediated SERS technique was successfully applied to detect lactic acid at physiological concentrations in the blood. Copyright © 2010 John Wiley & Sons, Ltd.
Raman spectroscopic study of the hydroxy‐arsenate‐sulfate mineral chalcophyllite Cu18Al2(AsO4)4(SO4)3(OH)24·36H2O
Authors: Frost Ray L. , Palmer Sara J. , Keeffe Elle C.
Published: February 2010

The mixed anion mineral chalcophyllite Cu18Al2(AsO4)4(SO4)3(OH)24·36H2O has been studied by using Raman and infrared spectroscopies. Characteristic bands associated with arsenate, sulfate and hydroxyl units are identified. Broad bands in the OH stretching region are observed and are resolved into component bands. Estimates of hydrogen bond distances were made using a Libowitzky function. Both short and long hydrogen bonds were identified. Two intense bands at 841 and ∼814 cm−1 are assigned to the ν1 (AsO4)3− symmetric stretching and ν3 (AsO4)3− antisymmetric stretching modes. The comparatively sharp band at 980 cm−1 is assigned to the ν1 (SO4)2− symmetric stretching mode, and a broad spectral profile centred upon 1100 cm−1 is attributed to the ν3 (SO4)2− antisymmetric stretching mode. A comparison of the Raman spectra is made with other arsenate‐bearing minerals such as carminite, clinotyrolite, kankite, tilasite and pharmacosiderite. Copyright © 2010 John Wiley & Sons, Ltd.
Corrosion behavior of hydrophobic titanium oxide film pre‐treated in hydrogen peroxide solution
Authors: Wang M. , Wang W. , He B. L. , Sun M. L. , Bao Y. S. , Yin Y. S. , Liu L. , Zou W. Y. , Xu X. F.
Published: February 2010

Hydrophobic titanium oxide (TiO2) film formed on metallic titanium substrate in hydrogen peroxide solution with a subsequent oxidation under air atmosphere. Component, microstructure, and hydrophobicity of the oxide film were characterized by X‐ray diffraction, scanning electron microscope, and water contact angle methods. Corrosion resistance tests were carried out in seawater solution at different heating temperature conditions. Electrochemical impedance spectroscopy techniques and polarization curves were used to study the changes and the corrosion resistance of the TiO2 film. The results demonstrate that the pre‐treated TiO2 film heated at 400 °C environment owns small special groove‐shaped structure on its surface, which induce higher hydrophobic capability, larger impedance, and better electrochemical stability than the film that was prepared at other temperatures or the Ti with nature formed oxidation film. It would be an ideal candidate as engineering material in deep seawater environment.
Cerium‐based thermal conversion treatments on silicon carbide reinforced 2009 aluminum alloy composites
Authors: Aziz I. , Zhang Q. , Du J.
Published: February 2010

The conversion coatings on SiCp/2009 aluminum (Al) composites and 2009 Al alloy were obtained by immersing the samples into the cerium (Ce)‐based solutions with varying the chemical concentration (CeCl3·7H2O, NaCl), solution pH/temperature, immersing time, and drying temperature. The corrosion inhibition mechanism and kinetics were studied by using the electrochemical techniques and surface analyses. Potentiodynamic polarization tests showed that coatings improved corrosion resistance as compared to untreated samples and environmental factors played important role in the formation of conversion layer. Scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), and X‐ray photoelectron spectroscopy (XPS) analysis revealed that relatively high inhibition efficiency for composite with 25 vol% SiCp was due to the existence of rather high surface area of cathodic intermetallics/SiCp, which support to deposit Ce oxides/hydroxides on the entire surface.
Co‐effect of bis(cyclohexanone) oxalyldihydrazone and copper(II) ion on the corrosion of cold rolled steel in 0.5 M hydrochloric acid solution
Authors: Qu Q. , Gao G. , Guo H. , Li L. , Ding Z.
Published: February 2010

Effects of bis(cyclohexanone) oxalyldihydrazone (BCO) and copper(II) ion (Cu2+) on the corrosion of cold rolled steel (CRS) in 0.5 M hydrochloric acid (HCl) solution were investigated using Tafel polarization curve and electrochemical impedance spectroscopy (EIS) at 20 °C. Results elucidate that the inhibition efficiency increases with increase in BCO concentration, and the addition of 10−5 M Cu2+ significantly enhances the inhibition efficiency of BCO. Polarization curve results elucidate that the single BCO acts as a mixed‐type inhibitor while the combination of Cu2+ and BCO acts as cathodic inhibitor. Ultraviolet and visible spectrophotometer (UV–Vis) results show that BCO molecules do not interact with Cu2+ and Fe2+ in 0.5 M HCl solution. Atomic force microscope (AFM) result indicates that a protective layer forms on CRS surface after immersion in 0.5 M HCl containing BCO in the absence and presence of Cu2+. The adsorption of BCO is found to follow the Langmuir adsorption isotherm in the presence and absence of Cu2+. The mechanism of typically chemical adsorption is proposed via the value of free energy of adsorption (ΔG) in the presence of BCO and Cu2+.
Corrosion behaviors of carbon steel in 55% LiBr solution containing PWVA inhibitor
Authors: Hu X. Q. , Liang C. H. , Wu X. N.
Published: February 2010

The inhibition performance of PWVA inhibitor on carbon steel was studied in 55% LiBr + 0.07 mol/L LiOH solution. Results indicated that PWVA inhibitor decreased both anodic and cathodic polarization current density and widened the passive potential region of carbon steel in the test solution. It could be classified as mixed inhibitor. PWVA has a strong oxidizability. It could form an intact and compact film which consisted of Fe2O3 on carbon steel surface in the test solution. The passive film retarded Br− which corroded the metal matrix in the test solution. When the concentration of PWVA was 300 mg/L, it showed an excellent inhibition effect. However, when the temperature was higher than 173 °C, the corrosion rate of carbon steel in 55% LiBr + 0.07 mol/L LiOH solution increased rapidly.
Corrosion behavior of newly developed Ti–Ag–Fe dental alloys in neutral saline solution
Authors: Zhang B. B. , Wang B. L. , Li L. , Zheng Y. F.
Published: February 2010

The corrosion behavior of Ti–5Ag–xFe alloys (x = 1, 2.5, 5 wt%) in neutral saline solution was investigated by the open‐circuit potential (OCP), potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and potentiostatic tests. The microstructural observation indicated that β‐Ti phase was retained by the addition of Fe into Ti–Ag alloys. Compared with commercially pure (CP) Ti, Ti–5Ag–xFe alloys exhibited higher corrosion potentials, lower current densities, and larger impedance, these suggested that Ti–5Ag–xFe alloys have nobler electrochemical corrosion behavior when compared with CP Ti in neutral saline solution.
The possibility for formation of macro‐cell corrosion in a liquid with low electrical conductivity
Authors: Matsumura M.
Published: February 2010

The possibility of electrochemical corrosion of carbon steel at the rate of 3.25 × 10−5 A/cm2 in water was examined under the conditions present during an accidental pipe rupture at the Mihama nuclear power plant: liquid conductivity, 7.5 µS/cm; dissolved oxygen concentration, 5 ppb or less; pH 8.6∼9.3; ferrous ion concentration, 20 ppb or less; temperature, 142 °C. The corrosion rate of iron in a micro‐cell with a dissolved oxygen reduction cathode was estimated to be only 1/400 of the preceding rate. On the other hand, that in a micro‐cell with a hydrogen ion reduction cathode was estimated to be as high as 1/10 of the preceding rate, that is, 3.25 × 10−6 A/cm2. Two important factors may have influenced the corrosion rate: the remarkable wall thinning, which must have been the direct cause of the rupture of the pipe, was located close to, and downstream from, an orifice; and, the water temperature was in the range at which carbon steel makes a transition from the active to the passive state. Taking these facts into consideration, it appears possible that micro‐cells with different corrosion rates might be generated and integrated into a macro‐cell, where the iron dissolution rate might be accelerated to as much as 10 times that of the micro‐cell.
Effect of surface oxidation treatment on the tribological performance of carbon fiber reinforced polyimide composites
Authors: Li J. , Xu Z. S.
Published: February 2010

The effect of ozone surface treatment of carbon fibers (CF) on the tensile strength and tribological properties of carbon fiber reinforced polyimide (CF/PI) composite was investigated. Experimental results revealed that the tensile strength of ozone and air oxidation treated CF reinforced PI composite was improved compared with that of untreated composite. Compared with the untreated and air‐oxidated CF/PI composite, the ozone treated composite had the lowest friction coefficient and specific wear rate under given applied load and reciprocating sliding frequency. Ozone treatment effectively improved the interfacial adhesion between CF and PI. The strong interfacial adhesion of the composite made CF not easy to detach from the PI matrix, and prevented the rubbing‐off of PI, accordingly improved the friction and wear properties of the composite.
Empirical formulas for description of the fatigue crack growth rate
Authors: Rozumek D.
Published: February 2010

The paper presents the test results obtained for fatigue crack growth in flat specimens subjected to bending. The tests were conducted for different loading amplitudes and different load ratios using the ΔJ parameter. Accuracy of description of the fatigue crack growth rate was tested with use of different empirical formulas. One‐side restrained specimens made of 10HNAP steel were tested. In each tested specimen, there was the external notch 5 mm in depth, and the notch rounding radius was ρ = 0.2 mm. The tests were carried out at the fatigue test stand MZGS‐100 under loading frequency 28.8 Hz. It has been found that the obtained results depend on the applied empirical formula.
DJ‐1, PINK1, and their effects on mitochondrial pathways
Authors: Cookson Mark R.
Published: February 2010

Genetic forms of parkinsonism are interesting for two particular reasons. First, finding a gene identifies a cause for a disease that would otherwise be unexplained. Second, finding several genes for the same disorder allows us to reconstruct molecular pathways that, in the example of Parkinson's disease, are be associated with the survival of dopamine neurons in the substantia nigra. Two rare causes of parkinsonism, DJ‐1 and PINK1, are associated with mitochondria. This organelle has long been linked with Parkinson's disease, and recent results are starting to show how mutations impact mitochondrial function. In this short review, I will discuss how we can use some of this information to understand why it is that neurons become dysfunctional in PD. © 2010 Movement Disorder Society
The biology and pathology of the familial Parkinson's disease protein LRRK2
Authors: Dauer William , Ho Cherry Cheng‐Ying
Published: February 2010

Parkinson's disease (PD) is typically a sporadic illness, but the past decade has witnessed the identification of mutations responsible for multiple familial forms of the disease. The proposed functions of some of these genes (e.g., E3 ubiquitin ligase, redox‐dependent chaperone) have led to the hypothesis that dysfunction of protein quality control pathways contributes to PD neurodegeneration. However, the key signaling events that act downstream of misfolded proteins to cause cell death remain poorly defined. The discovery of the familial PD kinase leucine‐rich repeat kinase 2 (LRRK2) holds great promise for the elucidation of signaling events relevant to PD neurodegeneration. This review will summarize current knowledge of the clinical and cell biological features of LRRK2, the most common inherited cause of Parkinsonism. © 2010 Movement Disorder Society
Advances in environmental epidemiology
Authors: Tanner Caroline M.
Published: February 2010

Parkinson's disease (PD) is likely due to the combined effects of environment and genes in most cases. Environmental factors inversely associated with PD (or, putative protective factors) include cigarette smoking, use of coffee/caffeine, higher uric acid levels, and anti‐inflammatory drug use. Less well‐established inverse associations with PD include higher cholesterol levels, statin use, higher dietary vitamin B6, and night shift work. Putative risk factors are pesticide exposure, head trauma, certain occupations, and milk consumption. The pathogenesis of PD may begin decades before motor symptoms. PD may have shared determinants with other neurodegenerative disorders involving abnormal protein aggregation. © 2010 Movement Disorder Society
Mitochondrial therapies for Parkinson's disease
Authors: Thomas Bobby , Beal M. Flint
Published: February 2010

Parkinson's disease (PD) is marked by widespread neurodegeneration in the brain in addition to a selective yet prominent and progressive loss of nigrostriatal dopaminergic neurons. Of the multiple theories suggested in the pathogenesis of PD, mitochondrial dysfunction takes a center stage in both sporadic and familial forms of illness. Deficits in mitochondrial functions due to impaired bioenergetics, aging associated increased generation of reactive oxygen species, damage to mitochondrial DNA, impaired calcium buffering, and alterations in mitochondrial morphology may contribute to improper functioning of the CNS leading to neurodegeneration. These mitochondrial alterations suggest that a potential target worth exploring for neuroprotective therapies are the ones that can preserve mitochondrial functions in PD. Here, we provide a recent update on potential drugs that are known to block mitochondrial dysfunctions in various experimental models and those that are currently under clinical trials for PD. We also review novel mitochondrial survival pathways that provide hope and promise for innovative neuroprotective therapies in the future that can be explored as possible therapeutic intervention for PD pathogenesis. © 2010 Movement Disorder Society