bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polarized Raman scattering and phase transition studies of n‐diethylenediammonium monohydrogenmonophosphate dihydrate
Authors: Elleuch S. , Feki H. , Abid Y. , Mlayah A. 
Published: May 2006

AbstractPolarized Raman scattering studies at room temperature were carried out on N‐diethylenediammonium monohydrogenmonophosphate dihydrate single crystal samples, abbreviated N‐DDHP. An assignment of the normal modes is proposed based on group theory analysis and correlations with previous data reported for other homologous hydrogen‐bonded systems. A careful analysis of the vibrational spectra shows that the assignment of the fundamental vibrational modes can be done based on phosphate, organic and water group vibrations. In addition, differential scanning calorimetry measurement and a Raman spectroscopic study at several temperatures in the range 100–300 K are presented. The occurrence of a low‐temperature phase transition near 220 K is well evidenced. From the temperature‐dependence behavior of some internal and external modes, this transition is interpreted by an order–disorder transition which involves the structural modifications of both anion and cation groups. Copyright © 2006 John Wiley & Sons, Ltd.
Simultaneous determination of aromatic and terpenic constituents of cloves by means of HPLC with diode array detection
Authors: Musenga Alessandro , Ferranti Anna , Saracino Maria Addolorata , Fanali Salvatore , Raggi Maria Augusta 
Published: May 2006

AbstractAn HPLC method has been developed for the simultaneous determination of aromatic and terpenic constituents of cloves on a C8 RP column, with the mobile phase consisting of a pH 3.5 phosphate buffer‐triethylamine (30%) and acetonitrile (70%); a flow rate of 1.2 mL/min and a diode‐array detector were used. Complete separation of all analytes (eugenol (EUG), eugenol acetate (AEUG), β‐caryophyllene, α‐humulene and caryophyllene oxide) was achieved within 7 min. Good linearity was found in the range 0.125–40.0 μg/mL for EUG and AEUG and in the range 0.250–20.0 μg/mL for the terpenic compounds. After validation, the method was successfully applied to the analysis of clove oil and clove extract samples. The results obtained indicate good accuracy (recovery percentage mean value corresponding to 99.9%) and satisfactory precision.
Dense subtrees in complete Boolean algebras
Authors: König Bernhard 
Published: May 2006

AbstractWe characterize complete Boolean algebras with dense subtrees. The main results show that a complete Boolean algebra contains a dense tree if its generic filter collapses the algebra's density to its distributivity number and the reverse holds for homogeneous algebras. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Silica‐supported bis(imino)pyridyl iron(II) catalyst: nature of the support–catalyst interactions
Authors: Ray Saptarshi , Sivaram Swaminathan 
Published: May 2006

AbstractEthylene polymerizations were performed using silica‐supported 2,6‐bis[1‐(2,6‐diisopropylphenylimino) ethyl] pyridine iron(II) dichloride with methylaluminoxane (MAO) as co‐catalyst. Silica was calcined at 600, 400 and 200 °C under vacuum for 8 h. The effect of calcination temperature of silica on the polymerization activity and the properties of the polymers obtained were examined. Catalyst–support interactions were examined by both a chemical method and XPS. It was observed that upon supporting the catalyst on the surface of silica, there is an increase in the binding energy of the metal center. However, no change in the metal binding energy was observed on supporting the catalyst to silica calcined at different temperatures. Ethylene polymerizations were performed using MAO as co‐catalyst. Catalysts were also prepared by first pretreating silica with MAO, followed by addition of the Fe(II) catalyst and contacting a complex of Fe(II) catalyst–MAO with silica previously calcined at 400 °C for 8 h. The results indicate that there is no chemical bonding between the support and the catalyst. Copyright © 2006 Society of Chemical Industry
Flame retardancy of different‐sized expandable graphite particles for high‐density rigid polyurethane foams
Authors: Shi Lei , Li Zhong‐Ming , Xie Bang‐Hu , Wang Jian‐Hua , Tian Chun‐Rong , Yang Ming‐Bo 
Published: May 2006

AbstractThe effects of expandable graphite (EG) of different particle sizes, on the fire‐retardant properties of high‐density rigid polyurethane foam (RPUF) (0.45 g cm−3) were studied. Samples of EG with different particle sizes were obtained by pulverization in an ultra‐high‐speed mixer for 4 and 13 min, respectively. It was shown that as received (EG0) and 4 min pulverized EG (EG4) efficiently improved the fire‐retardant properties of RPUF composites, while 13 min pulverized EG (EG13) did not. The char of the burned composites filled with EG0 and EG4 covered the whole surface of the samples and formed a complete physical barrier. This barrier material prevented combustible gases from feeding the flame and also isolated oxygen efficiently from the burning material. EG13 did not produce enough char to cover the whole surface of the burning sample, resulting in poor fire‐retardant property of the RPUF composites. Thermal degradation tests of the foams by thermogravimetric analysis indicated that EG showed negligible effects on the thermal stability of the RPUFs. Copyright © 2006 Society of Chemical Industry
Ligand‐field splitting of the energy levels of Nd3+ (4f3) in 2‐hydroxyethyl methacrylate polymer (HEMA)
Authors: Gruber John B , Sardar Dhiraj K , Johnson Dave , Yow Raylon M , Coeckelenbergh Cody H , Nijjar Anmol S 
Published: May 2006

AbstractDetailed absorption spectra of trivalent neodymium (Nd3+) in 2‐hydroxyethyl methacrylate polymer (HEMA) are reported at cryogenic temperatures and at wavelengths between 440 and 900 nm. The Nd3+ spectra are confirmed by comparison with spectra of HEMA samples prepared without inclusion of the rare earth ion. The structure observed on the absorption bands can be interpreted in terms of the ligand‐field (crystal‐field) splitting of the energy levels of Nd3+ (4f3) for multiplet manifolds, 4F3/2, 4F5/2, 2H9/2, 4F7/2, 4S3/2, 4F9/2, 2H11/2, 4G5/2, 2G7/2, 4G7/2, and 2K13/2. The Nd3+ ions are complexed as species made up of nitrate anions and H2O molecules that come from the neodymium nitrate hydrate salt used in the preparation of the doped HEMA sample. The local symmetry of the Nd3+ ion in HEMA is very low (possibly CS), and a number of different environments are likely for the neodymium species in the HEMA structure. We have calculated the ligand‐field splitting of the Nd3+ energy levels using a point charge/dipole model for one such possible species, Nd(NO3)3 · xH2O− (x = 5–6). The results of the model give an agreement of 10 cm−1 (rms) between 43 observed‐to‐calculated ligand‐field (Stark) levels. Comparisons between these same calculated levels and observed levels obtained for Nd3+ in crystalline hydrated nitrate salts and certain Nd3+‐doped glasses also give good agreement and support a better understanding of the environment of Nd3+ in a polymeric structure. Copyright © 2006 Society of Chemical Industry
Impact of III/V ratio on polytype and crystalline quality of AlN grown on 4H‐SiC (11$ \bar 2 $0) substrate by molecular‐beam epitaxy
Authors: Horita M. , Suda J. , Kimoto T. 
Published: May 2006

AbstractThe impact of the III/V ratio during growth on the polytype and crystalline quality of nonpolar AlN grown on 4H‐SiC (11$ \bar 2 $0) was investigated. Growth of AlN was carried out by molecular‐beam epitaxy (MBE) using elemental Al and rf‐plasma excited nitrogen. Polytype replication from the SiC substrate to the grown AlN epilayer occurred under Al‐rich conditions, i.e., 4H‐AlN (11$ \bar 2 $0) was grown on 4H‐SiC. On the other hand, the thermally stable 2H‐AlN (11$ \bar 2 $0) polytype was grown under N‐rich conditions. The best crystalline quality of AlN was obtained for slightly Al‐rich conditions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Energy gaps and bowing parameters of InAlGaN ternary and quaternary alloys
Authors: Androulidaki M. , Pelekanos N. T. , Tsagaraki K. , Dimakis E. , Iliopoulos E. , Adikimenakis A. , Bellet‐Amalric E. , Jalabert D. , Georgakilas A. 
Published: May 2006

AbstractWe report a study of band gap energies and bowing parameters of all possible families of ternary and quaternary nitride alloys. The experimental band gap energies (E g) measured by photoluminescence, optical transmission and reflection methods, were strain‐corrected in order to obtain for every sample the unstrained value of its E g. For Alx Ga1–x N the bowing parameter is equal to 1 eV, but the alloys Inx Ga1–x N and Inx Al1–x N exhibited strong dependence of the bowing parameter on alloy composition. Finally, we investigated many quaternaries alloys Inx Aly Ga1–x –y N and we observed that the bowing parameter appears also to be very sensitive on In content. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the incorporation mechanism of Fe in GaN grown by metal‐organic vapour phase epitaxy
Authors: Balmer R. S. , Soley D. E. J. , Simons A. J. , Mace J. D. , Koker L. , Jackson P. O. , Wallis D. J. , Uren M. J. , Martin T. 
Published: May 2006

AbstractWe report an investigation of the incorporation mechanism of iron (Fe) as a dopant in GaN grown by MOVPE. A series of Fe doped GaN structures were studied by secondary ion mass spectrometry (SIMS), atomic force microscopy (AFM) and X‐ray photo‐electron spectroscopy (XPS). A model is presented which describes the SIMS concentration profiles with excellent agreement, and, it is shown that Fe incorporation into GaN occurs via a surface segregation mechanism. This model is supported by direct measurement of a highly Fe‐rich layer on the surface of Fe doped GaN by XPS. Furthermore, we find that the presence of Fe on the GaN surface promotes a transition from 2D to 3D GaN growth which is confirmed by AFM measurements of RMS roughness with increasing Fe flux. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication and characterization of Ni‐based Schottky‐type AlxGa1–xN ultraviolet photodetectors with different buffer conditions
Authors: Park Ki Yon , Kwon Bong Joon , Son Jeong Hwan , Cho Yong‐Hoon 
Published: May 2006

AbstractWe investigated the structural, optical, and electrical properties of Ni‐based Schottky type AlxGa1–xN ultraviolet (UV) photodetectors. Three different types of AlxGa1–xN/GaN heterostructures were epitaxially grown on (0001) sapphire substrates by metal‐organic chemical vapor deposition. We found that the thin AlxGa1–xN layer directly grown on the optimized GaN buffer layer showed the most excellent crystal quality and opto‐electrical properties of Ni‐based Schottky type UV photodetectors. We obtained a dark current of 0.1 nA at –1 V, a responsivity of 0.150 A/W at zero bias, and a specific detectivity D* of 1.28 × 1014 cmHz1/2W–1 at λ = 300 nm for UV photodetectors with a 0.15‐µm‐thick AlxGa1–xN layer directly grown on a 3‐μm ‐ thick undoped GaN layer. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantitative strain analysis of GaN/AlN quantum dot multilayers
Authors: Sarigiannidou E. , Andreev A. D. , Monroy E. , Daudin B. , Rouvière J. L. 
Published: May 2006

AbstractThe strain distribution in vertically‐correlated GaN quantum dot layers embedded in an AlN matrix is investigated from high‐resolution transmission electron microscopy images. The quantitative strain analysis is realized using the geometrical phase analysis. The obtained results are further supported by elastic theoretical calculations carried out using a combination of Fourier transform and Green's function techniques. We find that the AlN spacers situated between consecutive wetting layers are almost fully relaxed. On the contrary, the AlN spacers located between the vertically correlated GaN quantum dots (QDs) are found to be in a tensile strain state. This local strain is generated by the GaN QDs on the surrounding AlN matrix and causes the vertical alignment of the dots inside the multilayer structure. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In‐vitro responses to ascorbate and manganese in fibroblasts from a patient with prolidase deficiency and iminodipeptiduria: Cell growth, prolidase activity and collagen metabolism
Authors: Myara I. , Charpentier C. , Wolfrom C. , Gautier M. , Lemonnier A. , Larregue M. , Chamson A. , Frey J. 
Published: May 2006

AbstractAfter successful ascorbate and manganese treatment of a female patient with prolidase deficiency and iminodipeptiduria, we attempted to explain the mechanism of action of these drugsin vitro, using them preferentially on skin fibroblasts. Sincein vivo, ascorbate and manganese seemed to be responsible for both biochemical and clinical improvement, they were also expected to activate prolidase activityin vitro. Cell growth and prolidase activity were accordingly observed in fibroblast cultures supplemented with these compounds. It seemed that only ascorbate accounted for the successfulin vivo response. To understand the mechanism involved, we studied collagen metabolism and found a decreased proline pool, a massive increase of rapidly degraded collagen and moderate enhancement of type III collagen and type I trimer in the patient's fibroblasts. We believe that ascorbate allowed the prolidase‐deficient cells to maintain a normal collagen pool by increasing collagen synthesis. Both the massive increase in cell growth in response to ascorbate and the bad response as regards the quality of the collagen produced confirm the secondary nature of this mechanism. However, the relationship between accelerated collagen catabolism and prolidase deficiency remains unclear.
Testicular tumors in children
Authors: Filler Robert M. , Hardy Brian E. 
Published: May 2006

AbstractAlthough relatively rare, testicular neoplasms affect a significant number of young children each year. The most common tumor is embryonal carcinoma. With proper management, which includes orchiectomy and retroperitoneal lymph node dissection, survival rates as high as 80% can be expected for children with stage A disease. The use of adjunctive chemotherapy in early stages of embryonal carcinoma may reduce the failure rate even further. Salvage of more advanced cases is possible with the addition of chemotherapy and radiation. Similar results have been obtained in the treatment of other malignant tumors of childhood. Benign tumors of the testis are less frequent than malignant ones and present no special problems in management.
Restraint‐induced stress ulcer. I. Hypothalamic, urinary, and adrenal biochemical studies
Authors: Balibrea Jose L. , Gomez Jose , Alemany Jose R. , Aznar Jose , Canela Mercedes , Castells Enrique , Fernandez Jose L. , Barreno Pedro G. , Ruiz Javier 
Published: May 2006

AbstractThe purpose of these experiments was to study the incidence of stress ulcers in restrained rats and to correlate it with hypothalamic and adrenal cortical and medullary activity, with and without vagotomy. A total of 217 adult rats were used, grouped into 56 sets, and distributed at random in 5 experimental groups. Restraint was followed by a 79% incidence of ulceration in the glandular portion of the gastric mucosa. Vagotomy made these worse (p<0.01). Hypothalamic levels of catecholamines and serotonin showed no significant changes. Urinary measurements revealed decreased excretion of 17‐ketosteroids (p<0.001), increased excretion of uropepsinogen (p<0.01), and no significant changes in vanillylmandelic acid among the rats submitted to immobilization. In the adrenal glands of stressed animals, there was a decreased level of catecholamines (p<0.01) and no significant changes in corticosteroid content (17‐ketosteroids). These results suggest that hypothalamic stimulation and the participation of the adrenal glands are not essential factors in the pathogenesis of restraint‐induced experimental stress ulcer.
Percutaneous needle arteriography
Authors: McCollum Charles H. , Garcia‐Rinaldi R. , Graham J. M. , Noon George P. , DeBakey Michael E. 
Published: May 2006

AbstractSuccessful arterial reconstructive surgery requires exact definition of the occlusive or aneurysmal process and the condition of the distal arterial tree. To define these two parameters, it is essential that arteriography be precise, yet it must be safe and reproducible. At our institution, we continue to utilize percutaneous needle arteriography because of its safety and excellent delineation of the vascular system. The purpose of this paper is to discuss our indications, techniques, and results of percutaneous arteriography for evaluation of peripheral arterial disease. During 1975, 1,253 percutaneous arteriograms were performed under general anesthesia by the surgical team. The techniques for carotid, vertebral (retrograde brachial), and femoral arteriograms, and translumbar aortograms will be reviewed. There were no deaths and only 8 (0.7%) complications. We believe that this technique provides an excellent method for good preoperative evaluation of the arterial system of the peripheral arteries and abdominal aorta.
Treatment of benign strictures of the bile ducts
Authors: Fernández Manuel 
Published: May 2006

AbstractIn 2720 operations on the bile ducts, we have repaired 52 strictures caused by accidental injuries. In 39 cases the strictures were located at the level of the bifurcation of the common hepatic duct. The surgical treatment in 39 cases consisted of left hepaticojejunostomy described by Hepp‐Couinaud, which involves a side‐to‐side anastomosis between a defunctionalized jejunal limb and the left hepatic duct. The average size of the anastomotic stoma was 35 mm in diameter. A single layer of interrupted sutures of absorbable material was used. No internal drains or stents were employed. Clinical and laboratory follow‐up examinations carried out between 1 and 10 years postoperatively showed excellent results in all cases. There were no recurrences of stricture and no surgical or postoperative deaths. Morbidity rate was low and was due mainly to some infections of the surgical wound and small drainage of bile in the immediate postsurgical period. All the patients treated were able to return to normal life within a period of 15 to 20 days.
Surgical application of tissue adhesives
Authors: Petrovsky Boris V. , Gigaury Vladimir S. , Milonov Oleg B. , Perelman Michael I. , Mlinchik Vyacheslav E. , Gotye Sergey V. , Safarov Iskandar S. 
Published: May 2006

AbstractA new technique of application of cyanoacrylate tissue adhesive has been evaluated in 180 patients with wounds of the liver (77 patients), spleen (12 patients), pancreas (9 patients), and lung (82 patients). The technique involves injection of the tissue adhesive with a specially adapted jet injector, so that it penetrates 3–5 mm deep into the parenchyma to form an adhesive plug. The cyanoacrylate adhesive was tolerated without complications, and was highly successful in controlling bleeding, leakage of bile and pancreatic juice, and leakage of air. The adhesive plugging technique warrants widespread application in the surgery of parenchymatous organs.
Dermatitis due to zinc deficiency associated with prolonged malnutrition and total parenteral nutrition
Authors: Hamit Harold F. , David Hamer E. , Stevens James C. 
Published: May 2006

AbstractZinc is an essential element in over 70 metalloenzymes that are involved in a wide variety of biochemical reactions and physiological processes such as synthesis of RNA and DNA, the immune response, wound healing, growth and development, utilization of vitamin A, and maintaining the integrity of membranes of cells and organelles. Zinc deficiencies are rare under normal circumstances because the usual diets throughout the world contain ample zinc to meet normal human daily requirements of about 15 mg. Deficiencies of zinc usually result from unusual diets with high cereal content and little or no animal proteins, and are manifested clinically by such disorders as hypogonadal dwarfism, hepatosplenomegaly, anemia teratogenesis, impaired senses of taste and smell, and dermatologic problems, including acrodermatitis enteropathica. We have added 2 case reports to the recently reported cases of acute dermatoses, with lesions resembling those of acrodermatitis enteropathica, associated with total parenteral nutrition and due to zinc deficiency resulting from inadequate intake of zinc and increased excretion of zinc in patients who already may have been depleted from nutritional disturbances that placed them in a catabolic state. Amino acid solutions for total parenteral nutrition, especially the newer crystalline amino acid solutions, contain amounts of zinc that are inadequate for these patients. The acute dermatoses resemble impetigo caused by bacteria, yeast, or fungi, but do not respond to appropriate treatment for these kinds of lesions. They respond readily to parenteral zinc therapy and probably can be prevented by giving adequate zinc parenterally during total parenteral nutrition.
Diaphanography: A method for evaluation of the female breast
Authors: Ohlsson Björn , Gundersen Jörgen , Nilsson Dag‐Martin 
Published: May 2006

AbstractDiaphanography involves transillumination of the breast with photographic registration on an intrared film. It has been used to evaluate 2 populations of patients. First, 200 women referred to our hospital were examined. In 107 patients operation was performed and the results were compared to the preoperative diaphanographic investigation. There was a good correlation between the preoperative and operative findings. Second, 1575 women without symptoms from the breast were investigated and 11 cancers were found in 10 patients. The diaphanographic method is of value both as a screening technique and as an aid in classifying palpable tumors of the breast.
The potential impact of needle biopsy on surgery for thyroid nodules
Authors: Block Melvin A. , Miller J. Martin , Kini Sudha R. 
Published: May 2006

AbstractCurrent techniques with fine and cutting needle biopsies permit greatly improved selection of patients with thyroid nodules for operation. A diagnosis of definite or probable carcinoma was confirmed in 95% of 76 patients, and the addition of the category of indeterminate cellular nodule resulted in an overall frequency of carcinoma in 86%. Therefore, the frequency of operations for benign thyroid nodules was dramatically decreased. Critical for the use of needle biopsy of the thyroid is experience in obtaining an adequate and representative sample of the nodule, as well as in cytologic and histologic interpretation of the tissue. Results of needle biopsy of thyroid nodules should be correlated with clinical findings even though the latter criteria provide a much less accurate index of the need of operation.The frequency of carcinoma in patients selected for operation can be increased from the 15% to 30% experienced in the past to a level of approximately 85% by needle biopsy. Thyroid nodules that are recognized as cellular by needle biopsy, but in which carcinoma cannot be ruled out should be treated surgically. Improved selectivity for operation for thyroid nodules has not yet significantly reduced the total number of patients undergoing operation in our practice. Some thyroid nodules that would have been treated nonoperatively in the past are now recognized as needing surgery. Operative eradication of nodules that have been considered clinically benign and managed as such in the past, but which are now recognized as being actual or possible carcinoma by needle biopsy conceivably will reduce the frequency of anaplastic or invasive carcinoma in the future. Falsenegative results have been recognized in 1% or less of patients. A preoperative diagnosis of thyroid carcinoma by needle biopsy permits an immediate, definitive surgical procedure, and changes the operative approach for such patients. Needle biopsy of thyroid nodules can reduce procrastination in making a decision for a surgical or medical approach to the management of thyroid nodules.