While the etiology of Parkinson's disease remains largely elusive, there is accumulating evidence suggesting that mitochondrial dysfunction occurs prior to the onset of symptoms in Parkinson's disease....Full Text Available
Radiation therapy has had a significant and an expanded role in the management of cancer of the pancreas during the last decade. In particular, for locally advanced disease, radiation therapy has improved the median survival of patients to 1 year. Intraoperative electron beam therapy has been applied to unresectable and resectable pancreatic cancer in an attempt to enhance local control of disease and to improve patient survival. This paper presents a survey of the role of radiation therapy in treatment of cancer of the pancreas, provides information on the radiobiological aspects of this treatment modality and details the physical and dosimetric characteristics of intraoperative radiation therapy with electrons. Presented are the design specifics of an applicator system, central axis beam data, applicator parameters, dose distribution data, shielding, treatment planning and means of verification. ...
Radiation therapy has had a significant and an expanded role in the management of cancer of the pancreas during the last decade. In particular, for locally advanced disease, radiation therapy has improved the median survival of patients to 1 year. Intraoperative electron beam therapy has been applied to unresectable and resectable pancreatic cancer in an attempt to enhance local control of disease and to improve patient survival. This paper presents a survey of the role of radiation therapy in treatment of cancer of the pancreas, provides information on the radiobiological aspects of this treatment modality and details the physical and dosimetric characteristics of intraoperative radiation therapy with electrons. Presented are the design specifics of an applicator system, central axis beam data, applicator parameters, dose distribution data, shielding, treatment planning and means of verification. ...
Objective:Parkinson disease (PD) may affect the autonomic nervous system and may cause constipation; however, few studies have explored constipation preceding the motor onset of...Full Text Available
Objectives. To assess the feasibility of treating musculoskeletal pain in the lower back and/or lower extremities in persons with Parkinson's disease (PD) with cranial electrotherapy...Full Text Available
To determine clinical predictors and accuracy of {sup 123}I-FP-CIT SPECT imaging in the differentiation of drug-induced parkinsonism (DIP) and Parkinson's disease (PD). Several clinical features and {sup 123}I-FP-CIT SPECT images in 32 patients with DIP, 25 patients with PD unmasked by antidopaminergic drugs (PDu) and 22 patients with PD without a previous history of antidopaminergic treatment (PDc) were retrospectively evaluated. DIP and PD shared all clinical features except symmetry of parkinsonian signs which was more frequently observed in patients with DIP (46.9%) than in patients with PDu (16.0%, p<0.05) or PDc (4.5%, p<0.01). Qualitatively {sup 123}I-FP-CIT SPECT images were normal in 29 patients with DIP (90.6%) and abnormal in all patients with PD, and this imaging technique showed high levels of accuracy. DIP and ...
Deep brain stimulation of the subthalamic nucleus (STN-DBS) is efficacious in treating the motor symptoms of Parkinson’s disease (PD). However, the impact of STN-DBS on the progression...Full Text Available
BackgroundCystic neoplasms of the pancreas are less common than solid tumors, and portend a better prognosis. They can be divided into serous and mucinous subtypes, with the former...Full Text Available
BackgroundMucinous cystic neoplasm (MCN) of the pancreas is basically cystic epithelial neoplasm, unilocular or multilocular, occurring almost exclusively in women.Case...Full Text Available
Background & Aimsβ-catenin signaling within the canonical Wnt pathway is essential for pancreas development. However, the pathway is normally down-regulated...Full Text Available
We report here a case of a pathologically proven solitary fibrous tumor of the pancreas. A 54-year-old man was referred to our hospital for further evaluation of a pancreatic mass that was found incidentally....Full Text Available
AIM: To investigate differential points of solid-pseudopapillary neoplasm (SPN) of the pancreas and pancreatic endocrine tumor (PET).METHODS: Ten cases of SPN and fourteen cases of PET were studied...Full Text Available
We report here on a case of localized lymphoid hyperplasia of the pancreas in a 70-year-old man which manifested as double lesions (uncinate process and tail) in the organ. The lesions were incidentally...Full Text Available
AIM: To improve the diagnosis of heterotopic pancreas by the use of contrast-enhanced computed tomography (CT) imaging and CT virtual endoscopy (CTVE).METHODS: A total of six patients with heterotopic...Full Text Available
A 23-year-old woman presented to our hospital with nonspecific pain in the abdomen. She underwent radiological investigations, which revealed a solid and cystic mass in the tail end of the pancreas....Full Text Available
Cystic neoplasms of the pancreas are increasingly recognized due to the expanding use and improved sensitivity of cross-sectional abdominal imaging. Major advances in the last decade have led to an...Full Text Available
Objective: To further delineate the clinicopathological and radiological features of solid pseudopapillary tumor (SPT) of the pancreas and summarize the surgical therapy strategy for this tumor. Methods:...Full Text Available
In spite of their rarity, cystic neoplasms of the pancreas are characterized by existing or potential malignancy that cannot be ignored during decisive process with regard to the choice of treatment....Full Text Available
Solid-pseudopapillary tumor (SPT) is a rare neoplasm of the pancreas that usually occurs in young females. It is generally considered a low-grade malignant tumor that can remain asymptomatic for several...Full Text Available
The typical MRI features of the most common pancreatic diseases, such as pancreatitis and adenocarcinoma of the pancreas, have been established. However, even in these common pancreatic disorders, MRI correlation with the underlying pathology is limited for clinical reasons. We emphasize MR-pathological correlation of inflammatory and neoplastic pancreatic changes, including pancreatitis, adenocarcinoma, acinar cell carcinoma, rare cystic and solid pancreatic neoplasms, and islet cell tumors. By highlighting the correlation of key pathological features with MR findings, a better understanding of the MR appearance of pancreatic pathology can be provided. In addition, MRI may prove a powerful tool in detection and characterization of pancreatic tumors. (orig.) [Deutsch] Das MR-tomographische Erscheinungsbild von Pankreatitiden und Adenokarzinomen des Pankreas, als den haeufigsten Pankreaserkrankungen, ist zwar ausreichend bekannt; allerdings ist ...
Parkinson's disease (PD) is the most common neurodegenerative movement disorder. Mutations in PTEN-induced kinase 1 (PINK1) are a frequent cause of recessive PD. Autophagy, a pathway for clearance of protein aggregates or impaired organelles, is a newly identified mechanism for PD development. However, it is still unclear what molecules regulate autophagy in PINK1-silenced cells. Here we report that autophagosome formation is promoted in the early phase in response to PINK1 gene silencing by lentivirus transfer vectors expressed in mouse striatum. Reduced PP2A activity and increased phosphorylation of PP2A at Y307 (inactive form of PP2A) were observed in PINK1-knockdown dopaminergic cells and striatum tissues. Treatment with C2-ceramide (an agonist of PP2A) reduced autophagy levels in PINK...
Abnormal intracellular deposition of aggregated ?-synuclein is the characteristic feature of a number of neurological disorders, including Parkinson's disease (PD). Although ?-synuclein is typically known as a cytosolic protein, a small amount is secreted by exocytosis in both monomeric and aggregated forms. The extracellular forms of ?-synuclein in human body fluids, such as cerebrospinal fluid (CSF) and blood plasma, might be a diagnostic target for PD and related diseases. Here, we characterized a new set of monoclonal antibodies against ?-synuclein, and using different combinations of antibodies, we established ELISA systems to specifically detect human ?-synuclein, mouse and human ?-synuclein together, and multimeric forms of ?-synuclein in biological samples. By employing the Tyramide signal amplification method, the sensitivity of the assay was significantly improved to detect a concentration as ...
Patients with heterotaxy syndrome often have complex cardiac and extracardiac anomalies requiring further detailed diagnostic evaluation. They often present severe cardiac failure early in life. Newer radiological modalities in the form of spiral computed tomography (CT) and three-dimensional reconstruction of spiral CT allow clear definition of the anatomy of these anomalies. A 59-year-old woman was diagnosed with polysplenia and multiple anomalies in an abdominal ultrasonography (US) during a control medical examination due to a trivial dietary mistake. She was then referred to our institution for further examination of these anomalies and an additional thoraco-abdominal computed tomography (CT) examination. The patient was totally asymptomatic at the time of admission. There was no significant past history and no abnormal laboratory data. We performed abdominal, pelvic and thoracic CT examinations using Somatom Siemens Emotion scanner. Non-enhanced sections were obtained with 8 mm ...
Background:Solid pseudopapillary tumor is a rare pancreatic neoplasm with uncertain to low malignant potential. This is an uncommon neoplasm with many pseudonyms, occurring...Full Text Available
Standard pancreatic resections, such as pancreaticoduodenectomy, distal pancreatectomy, or total pancreatectomy, result in an important loss of normal pancreatic parenchyma and may cause impairment...Full Text Available
Several randomized placebo-controlled trials have consistently shown antidyskinetic effects of amantadine in levodopa treated patients with advanced Parkinson's disease (PD). However, all of these were of short duration and there have been claims that the effect of amantadine on levodopa induced dyskinesias (LID's) wear off after about 9 months of treatment. This randomized placebo-controlled parallel-group study was performed to assess the long-term antidyskinetic effect of amantadine in 32 PD patients, who after having been on stable amantadine therapy for LID over at least one year- were switched in a double blind manner to amantadine or placebo and followed for 3 weeks. Dyskinesia duration and intensity were assessed by UPDRS IV items 32 and 33 as well as by patient's diaries. The primary outcome was the score change of UPDRS IV items 32 + 33 between baseline and 3 weeks after treatment as well as the between treatment ...
Neuronal cell death induced by oxidative stress is correlated with numerous neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and stroke. The causes of sporadic forms of age-related neurodegenerative diseases are still unknown. Recently, a correlation between paraquat exposure and neurodegenerative diseases has been observed. Paraquat, a nonselective herbicide, was once widely used in North America and is still routinely used in Taiwan. We have used differentiated Human Neuroblastoma (SHSY-5Y) cells as an in vitro model to study the mechanism of cell death induced by paraquat. We observed that paraquat-induced oxidative stress in differentiated SHSY-5Y cells as indicated by an increase in the production of cellular reactive oxygen species (ROS). Furthermore, apoptosis was evident as indicated by cellular and nuclear ...
and palladium silicides (Pd,Si) with a total. AES intensity ratio of Pd to Si of 35/65. Scanning Electron Microscopy. (SEM') of the Pd region shows that ...
Interaction of Yb-Pd-Si system components is studied, isothermal cross section of this system state diagram at 870 K is constructed. Five new ternary silicides are detected in the system: YbPd_5Si_3, Yb_3Pd_2_0Si_6, YbPd_2Si, YbPd_0_,_6_7Si_1_,_3_3, YbPdSi; the existence of one more -YbPd_2Si_2, earlier known, is confirmed. Crystal structure for all the compounds detected is determined and examined. Data on the materials magnetic properties are obtained. It is assumed that YbPd_2Si, YbPd_2Si_2 and YbPdSi compounds appear to be the Condo-systems. 10 refs., 3 figs., 3 tabs.
PURPOSE: To determine the recommended dose of radiotherapy when combined with full-dose gemcitabine and erlotinib for unresected pancreas cancer. METHODS AND MATERIALS: Patients with unresected pancreatic cancer (Zubrod performance status 0-2) were eligible for the present study. Gemcitabine was given weekly for 7 weeks (1,000 mg/m(2)) with erlotinib daily for 8 weeks (100 mg). A final toxicity assessment was performed in Week 9. Radiotherapy (starting at 30 Gy in 2-Gy fractions, 5 d/wk) was given to the gross tumor plus a 1-cm margin starting with the first dose of gemcitabine. A standard 3 plus 3 dose escalation (an additional 4 Gy within 2 days for each dose level) was used, except for the starting dose level, which was scheduled to contain 6 patients. In general, Grade 3 or greater gastrointestinal toxicity was considered a dose-limiting toxicity, except for Grade 3 anorexia or Grade 3 fatigue alone. RESULTS: A total of 20 patients were treated (10 men and 10 ...
To evaluate repeated hepatic intraarterial chemotherapy (HIC) as a palliative treatment option for unresectable cholangiocarcinoma and liver metastases of various origins that were progressive under systemic chemotherapy. Between 2002 and 2006, 55 patients were treated in 4-week intervals (mean five sessions). Combined gemcitabine/mitomycin was administered intraarterially within 1 h. Tumor response was evaluated after the third session according to RECIST. Treated tumor entities were colorectal carcinoma (CRC) (n = 12), breast cancer (BC) (n = 12), cholangiocarcinoma (CCC) (n = 10), pancreatic (n = 4), ovarian (n = 3), gastric, cervical, papillary (each n = 2), prostate, esophageal carcinoma, leiomyosarcoma (each n = 1), cancer of unknown primacy (CUP) (n = 5). All patients tolerated the treatment well without any major side effects or complications. In total, there were 1 complete response (CR), 19 partial responses (PR), 19 stable (SD) and 16 progressive ...
One- and two-dimensional long-period superstructures (LPS), based on the L1{sub 2} substructure, are systematically investigated for the noble metal-palladium alloys Cu-Pd, Ag-Pd and Au-Pd with first-principles methods. Notwithstanding the fact that the experimental phase diagrams of these systems yield totally different features, quite similar behaviour with respect to formation of low temperature ordered LPS-phases (Cu{sub 3}Pd: LPS 3, Ag{sub 3}Pd: LPS 3, Au{sub 3}Pd: LPS 2; {l_brace}Cu, Au{r_brace}Pd{sub 3}: L1{sub 2}, AgPd{sub 3}: not a ground state) is predicted. As a lever between via LDA obtained formation enthalpies and a thorough ground state scan, the cluster expansion method in conjunction with a genetic algorithm provides adequate means for the extraction of effective interactions, which also allow for an ...
1. Proteolytic enzyme activities were examined in the pancreas of zinc-deficient and control rats. 2. No change was detected in trypsin-plus-chymotrypsin activity. 3. Carboxypeptidase activity was...Full Text Available
BACKGROUNDSolid-pseudopapillary neoplasms (SPNs) are rare pancreatic tumors with malignant potential. Clinicopathologic characteristics and outcomes of patients with...Full Text Available
This case report describes the second known instance of a multifocal capillary pancreatic neoplasm. Both cases occurred in young African American females. A less-than-total pancreatectomy was performed...Full Text Available
Pancreatic cysts are challenging lesions to diagnose and to treat. Determining which of the five most common diagnoses—pancreatic pseudocyst, serous cystic neoplasm (SCN), solid pseudopapillary...Full Text Available
IntroductionLaparoscopic distal pancreatectomy has been described for more than a decade now and has been considered technically feasible, safe, and with reproducible outcomes. It...Full Text Available
A hitherto unrecognized variant of solid-pseudopapillary tumor (SPT) of the pancreas is reported. The tumor presented in the pancreatic tail of a 44-year-old female patient. It was a well-defined, solid...Full Text Available
Pd-induced surface structures on Si(1 1 3) have been studied by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). In the initial process of the Pd adsorption below 0.10 ML, Pd silicide (Pd{sub 2}Si) clusters are observed to form randomly on the surface. By increasing the Pd coverage to 0.10 ML, the clusters cover the entire surface, and an amorphous layer is formed. After annealing the Si(1 1 3)-Pd surface at 600 deg. C, various types of islands and chain protrusions appears. The agglomeration, coalescence and crystallization of these islands are observed by using high temperature (HT-) STM. It is also found by XPS that the islands correspond to Pd{sub 2}Si structure. On the basis of these results, evolution of Pd-induced structures at high temperatures is in detail discussed.
New ternary compounds on the ytterbium base YbPd_2Ge, YbPd_2Si, YbPdGe, YbPdSi, YbPtGe, YbPd_2Ge_2 and known compound YbPdSi_2 were obtained and investigated. Results of measuring the electric resistivity and magnetic susceptibility in the 4.2-300 K range are presented. It is found that YbPdGe, YbPtGe, YbPd_2Ge at low temperatures have magnetic phase transitions, investigations of which testify to dominant contribution of ferromagnetic ordering. The investigation results testify also to substantial effect of ytterbium crystalline environment on the physical properties of compounds under study.
This paper reports Palladium alloy compositions investigated for suitability as a nonreactive material for the processing of ceramic superconductors. Barium-based superconductors were tested on Pd-Au and Pd-Ag alloys for reactivity. Bismuth-based superconductors were tested on a Pd-Ag alloy. The least reactive was found to be 70% Pd-30% Ag for the barium-based high-temperature superconductors (HTSC), whereas 30% Pd-70% Ag was found to be least reactive for bismuth-based HTSC.
Palladium silicide was formed on the sol-gel derived SiO2 supported Pd catalysts prepared by ion-exchange method (Pd/SiO2-SG-ion). However, the catalysts exhibited superior performances than commercial SiO2 supported ones in liquid-phase semihydrogenation of phenylacetylene. It was probably due to an inhibition of a product of styrene, which is adsorbed on the surface of Pd, more strongly on Pd/SiO2-SG in which Pd is electron-deficient as shown by larger binding energy from XPS results.
... Abstract : The electric resistance in weak (diluted) solid solutions of the Pd-Ag and Fe-W systems, as wellAS THE Hall effect in a Pd-Ag system ...
Symplastic transport occurs between neighbouring plant cells through functionally and structurally dynamic channels called plasmodesmata (PD). Relatively little is known about the composition of PD or the mechanisms that facilitate molecular transport into neighbouring cells. While transmission electron microscopy (TEM) provides 2-dimensional information about the structural components of PD, 3-dimensional information is difficult to extract from ultrathin sections. This study has exploited high-resolution scanning electron microscopy (HRSEM) to reveal the 3-dimensional morphology of PD in the cell walls of algae, ferns and higher plants. Varied patterns of PD were observed in the walls, ranging from uniformly distributed individual PD to discrete clusters. Occasionally the thick walls of the giant alga Chara were fractured, revealing the surface morphology of ...
We have demonstrated in this work (1) that methane is readily activated at mild conditions (100{degree}C, 1 torr) over a relatively noble metal, Pd. This was observed using a stepped and kinked Pd(679) crystal (1), and other crystal faces are now being investigated to establish whether the cracking of the C-H bond of methane on Pd is structure sensitive or structure insensitive. Oxygen chemisorption is extremely structure sensitive: weakly bonded, highly reactive oxygen overlayers form on Pd(100) surface (2), while strongly bonded, moderately reactive oxygen overlayers form on Pd(111) and Pd(679). Reaction of the weakly bonded oxygen with surface carbide gives rise to CO{sub 2} over clean Pd(100) but to CO over halogen-doped Pd(100) (3--5). The effect of halogens is primarily ensemble-controlling, or oxygen-supply ...
We have demonstrated in this work (1) that methane is readily activated at mild conditions (100[degree]C, 1 torr) over a relatively noble metal, Pd. This was observed using a stepped and kinked Pd(679) crystal (1), and other crystal faces are now being investigated to establish whether the cracking of the C-H bond of methane on Pd is structure sensitive or structure insensitive. Oxygen chemisorption is extremely structure sensitive: weakly bonded, highly reactive oxygen overlayers form on Pd(100) surface (2), while strongly bonded, moderately reactive oxygen overlayers form on Pd(111) and Pd(679). Reaction of the weakly bonded oxygen with surface carbide gives rise to CO[sub 2] over clean Pd(100) but to CO over halogen-doped Pd(100) (3--5). The effect of halogens is primarily ensemble-controlling, or oxygen-supply ...
The solid-pseudopapillary tumor (SPT) of the pancreas is a rare type of exocrine pancreatic neoplasm. SPT predominantly affects young women and female children, and is usually discovered incidentally. This tumor is generally benign with a low incidence of malignancy. A 13-year-old girl was admitted to the hospital with a few weeks' history of mild abdominal pain and jaundice. On physical examination, there was no palpable mass. The laboratory tests showed increased SR, CRP, high bilirubin, amylase and lipase serum levels. Ultrasound imaging revealed a solid lesion in the region of the pancreatic head. On MRI, precise tumor localization in the head of the pancreas with pancreatic duct dilatation and compression of the common bile duct were visualized. Pancreaticoduodenectomy and cholecystectomy was performed with good clinical outcome. Microscopic and immunohistochemical studies indicated that tumor cells were typical of SPT without any signs of ...
Purpose of this item is to report the CT patterns of pancreatic mesenchymal lesions and to investigate the capabilities and limitations of this technique in terms of characterization. In selected cases, CT can provide virtually diagnostic information (lipoma and teratoma), or at least highly suggestive findings (NHL, plexiform neurofibroma, lymphangioma). Moreover, knowledge of the variable morphostructural patterns of mesenchymal hisototypes (SCH, Sarcoma etc.) permits to include them in the differential diagnosis of pancreatic masses. [Italian] Scopo di questo rapporto e' descrivere gli aspetti semeiologici dei tumori mesenchimali del pancreas con la TC verificandone le possibilita e i limiti per la caratterizzazione. Pur nella rarita' dei reperti considerati, la TC puo' consentire l'effettiva caratterizzazione in alcuni casi (lipoma, neurofibroma plessiforme, linfangioma) o includere anche istotipi meno comuni (Schwannoma, ...
The performance of Ag-promoted Pd/Al2O3 catalysts, which were prepared by the selective deposition of Ag onto Pd using a surface redox (SR) method, during acetylene hydrogenation was compared with that of catalysts prepared by impregnation. The Pd surface was more effectively modified with Ag added by SR, even when small amounts of Ag were added. The catalyst prepared by SR showed a higher ethylene selectivity than the one prepared by impregnation, because SR allowed both the preferential deposition of Ag on the low-coordination sites of Pd and a greater electronic modification of Pd by Ag.
Growth mechanisms and thermal stability of ion-beam-induced epitaxial Pd/sub 2/Si films are investigated using Rutherford backscattering and channelling techniques. Epitaxial growth of Pd/sub 2/Si films was observed at room temperature by argon ion implantation into as-deposited Pd/Si(111) structures and furnace-annealed Pd/sub 2/Si(polycrystalline)/Pd/sub 2/Si(epitaxial)/Si(111) structures. Some additional experiments to check the growth mechanisms are also presented, in which the implantation energies, substrate orientations and dose rates were changed. Finally, the stability of the ion-beam-induced epitaxial Pd/sub 2/Si films on subsequent furnace annealing is studied.
Growth mechanisms and thermal stability of ion-beam-induced epitaxial Pd/sub 2/Si films are investigated using Rutherford backscattering and channelling techniques. Epitaxial growth of Pd/sub 2/Si films was observed at room temperature by argon ion implantation into as-deposited Pd/Si(111) structures and furnace-annealed Pd/sub 2/Si(polycrystalline)/Pd/sub 2/Si(epitaxial)/Si(111) structures. Some additional experiments to check the growth mechanisms are also presented, in which the implantation energies, substrate orientations and dose rates were changed. Finally, the stability of the ion-beam-induced epitaxial Pd/sub 2/Si films on subsequent furnace annealing is studied.
Using Pd and Ag L3,2-edge x-ray-absorption near edge structures (XANES) and x-ray photoemission spectroscopy, we have investigated the charge distribution in a series of Pd-Ag alloys (Pd3Ag, PdAg, and PdAg3) from a local perspective. It is found that, relative to the pure element, both Pd and Ag gain d and lose non-d (s and p) charge upon alloying. The results are discussed in terms of band filling, rehybridization, electronegativity, and electroneutrality considerations. The possibility of using the L3,2-edge XANES white line to circumvent the need of an appropriate volume for charge transfer discussions and for other applications are noted.
The a.c. susceptibility and high field magnetization of TbRh{sub 2-x}Pd{sub x}Si{sub 2} and TbRu{sub 2-x}Pd{sub x}Si{sub 2} compounds were investigated up to 140 kOe. The (T, x) magnetic phase diagrams were determined. For both systems, an increase in the Pd content causes a decrease in the Neel temperature and changes the magnetization curves. (orig.)
The magnetic and electronic properties of non-Fermi liquid UCu{sub 4Pd} depend on annealing conditions. Local structural changes due to this annealing are reported from UL{sub III}- and Pd K-edge x-ray absorption fine-structure measurements. In particular, annealing decreases the fraction of Pd atoms on nominally Cu 16e sites and the U-Cu pair-distance distribution width. This study provides quantitative information on the amount of disorder in UCu{sub 4Pd} and allows an assessment of its possible importance to the observed non-Fermi liquid behavior.
Comparative analysis of diagnostic accuracy (dignity determination) in CT-guided fine-needle biopsy (141 patients), CT (141), ultrasonography (89), angiography (50), and cholegraphy (ERCP, 55), was carried out in suspected space-occupying lesions of the pancreas. With accuracy of 86%, sensitivity of 37% and specificity of 92% fine-needle biopsy was superior to imaging procedures. Additional comparison of the results concerning the patients and Roc curves confirm the statements. For reduction of the number of imaging investigations a diagnostic algorithm is proposed, that starts with diagnostic CT and subsequent fine-needle biopsy controlled by CT. This would result in a more adequate use of angiography and ERCP and in the elimination of ultrasonography. (author).
The purpose of this communication is to determine whether the solubility enhancements for cold-worked Pd-Ni alloys increase or decrease with atom fraction of Ni. Substitutional Ni atoms contract and Pd lattice, in contrast to the lattice expansion resulting from substitutional Ag in Pd. The Pd-Ni alloy system forms a continuous series of fcc solid solution alloys over the whole composition range. The solubility enhancements will also be determined for a series of homogeneous, ternary Pd[sub 1[minus]x]Ni[sub 1/2x]Ag[sub 1/2x] alloys for x in the range from 0 to 0.2. For this series of ternary alloys the fcc lattice parameters do not change significantly from that of pure Pd. The alloys used in this research were purchased from Tanaka Kikinzoku Kogyo K.K. The detailed experimental procedure has been described previously. The alloys were all deformed by ...
The title compounds were prepared by arc-melting of the elemental components. Whereas NdPdSi and SmPdSi are already present after the arc-melting, alpha-GdPdSi and alpha-TbPdSi are formed only during the annealing at 800 degC. The four compounds crystallize with the recently reported alpha-YbAuGe type structure, which was refined for alpha-GdPdSi: Pnma, a=2108.0(4) pm, b=433.9(1) pm, c=745.6(1) pm, Z=12, R=0.026 for 1447 structure factors and 62 variable parameters. The lanthanoid atoms are situated between two-dimensionally infinite nets of condensed, puckered hexagons formed by alternating palladium and silicon atoms, with Pd-Si distances varying between 251 and 262 pm. In the third dimension these nets are linked via weak Pd-Pd (300 pm), Pd-Si (283 pm), and Si-Si bonds (261 pm). The refinements of the occupancy ...
A solid pseudopapillary tumor is an uncommon tumor of the pancreas that rarely metastasizes to other organs and usually shows good prognosis. An extrapancreatic tumor arising from a solid pseudopapillary tumor is very rare. We report a case of an atypical extrapancreatic solid pseudopapillary tumor that arose from the great omentum and disseminated to the peritoneum, and discuss the radiologic findings, including the CT, US, and MRI.
A solid pseudopapillary tumor is an uncommon tumor of the pancreas that rarely metastasizes to other organs and usually shows good prognosis. An extrapancreatic tumor arising from a solid pseudopapillary tumor is very rare. We report a case of an atypical extrapancreatic solid pseudopapillary tumor that arose from the great omentum and disseminated to the peritoneum, and discuss the radiologic findings, including the CT, US, and MRI
The morphological aspects of ternary phase formation during the Pd-GaAs reaction have been studied by application of transmission electron microscopy (TEM) and Rutherford backscattering (RBS) techniques. The TEM images show that the first product phase, ''phase I'', forms during deposition of Pd onto (100) GaAs and exhibits the preferred orientation (0001)/sub I/ approx. // (01 anti 1)/sub GaAs/. In the presence of unreacted Pd, the second phase, ''phase II'', nucleates at large-angle grain boundaries in the phase I film as the annealing temperature increases above approx.250C. Energy dispersive analysis of x-rays and RBS suggest the nominal compositions Pd3GaAs and Pd4GaAs for phases I and II, respectively.
The initial growth process and surface structure of thin Pd(silicide) films on clean Si(111)-7x7 surfaces have been studied by low energy ion scattering (ISS) and LEED-Auger techniques. Considerable reaction between Pd and Si at room temperature is observed to extend up to 25 ML thickness of deposited Pd. Heat treatment of the room temperature film produced epitaxial silicide Pd/sub 2/Si(0001) films covered with the accumulated elementary Si layers of 1-2 ML thickness. Deposition of 1/3 ML Pd onto a heated substrate gives a Pd-embedded ordered surface of Si(111)-..sqrt..3x..sqrt..3R30/sup 0/, the feature being similar to the cases of Ag, Au/Si(111) systems.
The initial growth process and surface structure of thin Pd(silicide) films on clean Si(111)-7x7 surfaces have been studied by low energy ion scattering (ISS) and LEED-Auger techniques. Considerable reaction between Pd and Si at room temperature is observed to extend up to 25 ML thickness of deposited Pd. Heat treatment of the room temperature film produced epitaxial silicide Pd_2Si(0001) films covered with the accumulated elementary Si layers of 1-2 ML thickness. Deposition of 1/3 ML Pd onto a heated substrate gives a Pd-embedded ordered surface of Si(111)-#sq root#3x#sq root#3R30"0, the feature being similar to the cases of Ag, Au/Si(111) systems. (orig.).
Pd/Ag alloy hollow spheres have been synthesized in ethylene glycol solution by the solvothermal method and have been characterized extensively. TEM results have revealed the formation of Pd/Ag hollow spheres. Moreover, HRTEM results confirmed the formation of Pd/Ag alloy spheres, where the lattice fringe spacing is 0.229 nm corresponding to the (111) plane of Pd/Ag alloy. SEM, XRD and UV-vis results have further suggested the formation of alloy hollow spheres. The preliminary results showed the reaction time may be an importance factor influencing the formation of Pd/Ag alloy hollow spheres.
was to mount Pd-Ag terminated MLCCs onto gold plated mounting pads of a ... to protect against incorrect shipment of pure tin-plated MLCCs when Pd-Ag ...
Combining in situ Rutherford backscattering and electrical transport measurements on low-temperature hydrogen-implanted amorphous Pd/sub 80/Si/sub 20/ films, we have studied the correlation between the hydrogen content and the resistivity.
The applicability of in situ, real-time RBS is demonstrated by characterizing the growth of thin Pd_2Si films on Si left angle 111 right angle substrates using isothermal as well as non-isothermal annealing. In contrast to the currently fashionable in situ ramped resistance technique, it is possible to extract the activation energy from a single run with a constant heating rate. The results, which are in excellent agreement with the literature, will be compared for isothermal annealing, fitting an appropriate model for the growth process to data from a single run and a Kissinger-like analysis with different ramp rates. In situ, real-time RBS was also used to study marker motion during CrSi_2 formation in the Si left angle 100 right angle /Pd_2Si/Cr system. It is possible to distinguish between the following mechanisms: (1) CrSi_2 formation via dissociation of the Pd_2Si at the Pd_2Si/Cr interface and ...
tact materials ate Ti-Pd-Ag and the back surface reflector is formed from evaporated .... Ti-Pd-Ag, Dielectric Wraparound. BSR. Evaporated Aluminum ...
Pneumatic dilation (PD) is an effective treatment for achalasia cardia. Outcome of PD, however, varies among different studies. Recently, some groups started considering laparoscopic myotomy to be competitive...Full Text Available
Probability distributions of partial discharge (PD) and dielectric breakdown voltage were investigated for the typical components of oil-filled transformer insulation. The equi-probabilistic PD and BD V-t characteristics were obtained from experimental results in the time range from several ..mu..sec to 10 hours. The authors point out that there is a close relationship between the scattering of PD voltage and the inclination of V-t characteristics in a long term region for ac voltage.
This paper reported on a study in which partial discharge (PD) measurements were performed on 6 underground transmission cable circuits to determine the effectiveness of PD measurements on fluid fill cables. The cables were between 37 and 56 years old. PD activity was detected from the terminations of H11L and H3L Cable 2. However, for cables from H3L Basin TS to Mill Street junction, PD activity was detected originating from within the main cable insulation.
... where the total palladium concentration equals that of silicon, the concentrations of palladium associated with various palladium silicides (Pd(x)Si , ...
The solid state reaction between a Pd thin film and a Si substrate produces a single new phase, Pd/sub 2/Si, for temperatures <700/sup 0/C. When the substrate is a single crystal of (111) surface orientation, this process is particularly interesting because the silicide grows epitaxially. Growth of epitaxial interfacial Pd/sub 2/Si was the focus of this study using X-ray diffraction techniques.
Attempts to synthesize YPd[sub 2]Si-type representatives LnPd[sub 2]Al were successful only with Ln triple bond Ce, Pr, Nd. This orthorhombic structure (oP16; space group Pnma) is an ordered variant of the Fe[sub 3]C type. Only NdPd[sub 2]Al undergoes magnetic ordering above 2 K. (orig.)
In Ce(Ru{sub 1-x}Pd{sub x}){sub 2}Si{sub 2} the dilution of the transition metal leads to strong electronic effects resulting in the disappearance and the appearance of long-range magnetic order in CePd{sub 2}Si{sub 2} and CeRu{sub 2}Si{sub 2}, respectively. ((orig.)).
In Ce(Ru_1_-_xPd_x)_2Si_2 the dilution of the transition metal leads to strong electronic effects resulting in the disappearance and the appearance of long-range magnetic order in CePd_2Si_2 and CeRu_2Si_2, respectively. ((orig.)).
The effects of different exposure concentrations of palladium (Pd) on relative metallothionein (MT) response and bioaccumulation were investigated in zebra mussels (Dreissena polymorpha). The mussels were exposed to 0.05, 5, 50, and 500 ?g/L Pd2+ for 10 weeks under controlled temperature and fasting conditions. Relative MT contents were assessed by a modified Ag-saturation method, which allows to discriminate between MT bound to Pd (Pd-MT) and MT bound to unidentified metals (Ag-MT). Determination of metal contents resulted from atomic absorption spectrometry following a microwave digestion. For unexposed mussels and mussels exposed to 0.05 ?g/L Pd no metal accumulation could be detected. All other exposure concentrations resulted in detectable Pd accumulation in mussels with final tissue concentrations of 96 ?g/g (500 ?g/L), 45 ?g/g (50 ?g/L), and 9 ?g/g (5 ...
Hydrocarbon synthesis during CO hydrogenation over Pd/M-ZSM5 (M=H,Na,La) and Pd/SiO/sub 2/ has been investigated. Overall activity depended on the cation-exchanged form of the support and decreased in the order Pd/La-ZSM5 = Pd/Na-ZSM5 > Pd/H-ZSM5 > Pd/SiO/sub 2/. The zeolite-supported catalysts showed high selectivity towards saturated C/sub 2/-C/sub 6/ hydrocarbons, whereas Pd/SiO/sub 2/ favored methanol production. Increasing temperature and H/sub 2//CO feed ratio led to higher reaction rates, lower yields of C/sub 2/-C/sub 6/ products, and increased lighter hydrocarbons. A mechanical mixture of Pd/SiO/sub 2/ and Na-ZSM5 showed similar product distribution as Pd/Na-ZSM5. Infrared spectra of the catalysts under reaction conditions indicate the presence of adsorbed oxygenates on the zeolite. ...
Resistivity measurements were performed on Fe40 Ni40 B20 and Pd80 Si20 in order to improve the understanding of structural relaxation in amorphous metals. A model describing structural relaxation as a combination of chemical short range ordering (CSRO) an...
G6PD activity was assayed in 20 Sardinian heterozygotes for G6PD deficiency and related to that of LDH and MDH. One of these heterozygotes showed a deficient phenotype in all her follicles, while the...Full Text Available
The transformation of Pd/Si to Pd_2Si/Si is studied using Auger electron spectroscopy over a wide temperature range of 370-1020 K. The Pd film gets totally converted to Pd_2Si upon annealing at 520 K, and beyond 570 K, Si starts segregating on the surface of silicide. It is found that the presence of surface oxygen influences the segregation of Si. The time evolution study of Si segregation reveals that segregation kinetics is very fast and the segregated Si concentration increases as the temperature is increased. Scanning electron microscopy measurements show that Pd_2Si is formed in the form of islands, which grow as the annealing temperature is increased.
Membranes in Palladium and its alloys, in particular Pd/Ag alloys, are selectively permeable to hydrogen and can therefore be used to purify hydrogen. It is intended to use them as material for electrodes in fuel cells. As the manufacturing process of a substrate Pd/Ag-layer consists of several stages and is still not completely understood, it would be advantageous to be able to characterise separately the layers of noble metals obtained by electro-plating . Attempts are being made in this work to vary the cristallographical structure of the deposited alloy by the choice of test parameters and by sintering when depositing the Pd/Ag. The layers produced are to be examined using an interference microscope and X-ray diffraction. Moreover, the diffusion behaviour of the hydrogen is to be examined with an electro-chemical pulse method specifically developed for this purpose. figs., tabs., 27 refs.
Inert markers (evaporated tungsten and silver) were used in growth studies of silicides formed both by thermal annealing and by ion mixing in the Ni/Si, Pd/Si, and Cr/Si systems. The markers were initially imbedded inside silicides and backscattering spectrometry was used to determine the marker displacement after different processing conditions. The results obtained in thermal annealing are quite consistent with that found in previous investigations. Ni is the dominant diffusing species in Ni_2Si, while Si is the diffusing species in CrSi_2. In Pd_2Si, both Pd and Si are moving species with Pd the faster of the two. In contrast, in growth of silicides by ion irradiation Si is the faster diffusing species in all three systems.
Inert markers (evaporated tungsten and silver) were used in growth studies of silicides formed both by thermal annealing and by ion mixing in the Ni/Si, Pd/Si, and Cr/Si systems. The markers were initially imbedded inside silicides and backscattering spectrometry was used to determine the marker displacement after different processing conditions. The results obtained in thermal annealing are quite consistent with that found in previous investigations. Ni is the dominant diffusing species in Ni/sub 2/Si, while Si is the diffusing species in CrSi/sub 2/. In Pd/sub 2/Si, both Pd and Si are moving species with Pd the faster of the two. In contrast, in growth of silicides by ion irradiation Si is the faster diffusing species in all three systems.
Isotherms have been measured for H(D){sub 2}(g) solution in crystalline Pd{sub 9}Si{sub 2} in the temperature range from 235 to 373 K. The solubilities are significant, e.g., at 1.0 MPa (298 K), (H/Pd) = 0.052 or Pd{sub 9}Si{sub 2}H{sub 0.47}, however, there is no indication of hydride phase formation even down to 235 K at 1.0 MPa. The thermodynamic values for hydrogen solutions at infinite dilution of hydrogen are {Delta}H{degrees}{sub H}= -11.9 kJ/mole {1/2}H{sub 2} and {Delta}S{degrees}{sub H} = -50 J/K mole {1/2}H{sub 2}. The former is more negative than for Pd-H{sub 2} and the latter is somewhat more positive; but generally the values are not that different from Pd-H{sub 2}. The isotope effect is similar to that found for Pd-H(D){sub 2}.
Radiation defects produced by helium implantation were used to shape profiles of palladium (Pd) and platinum (Pt) atoms in-diffusing (for 20 min at temperatures 600-800 deg. C) either from surface silicide (Pd_2Si, PtSi) or implanted layers. Results show that this procedure allows a strong localization of substitutional Pd and Pt at the depth where the damage produced by helium peaks. This results in local reduction of carrier lifetime by an almost ideal recombination centers - the acceptor level of substitutional Pd (E _c - 0.22 eV) or Pt (E _c - 0.23 eV). While optimum conditions for Pt in-diffusion are about 700 deg. C, Pd gives the best results already at lower temperatures (600 deg. C) where it also exhibits higher peak solubility. Both methods were used for optimization of turn-off properties of high power PiN diodes. The devices, where the lifetime was killed locally by ...
The formation kinetics of Pd_2Si for fully silicided (FUSI) gate formation and the work function tuning of a Pd_2Si FUSI gate by impurity predoping were investigated. It has been found that the morphology and phase of a formed FUSI layer depend not only on the silicidation annealing temperature but also on the heating ramp-up rate and the presence of impurities. Fast ramp-up annealing was necessary to avoid defect formation, such as voids in the silicide film at the oxide interface, and to obtain a homogeneous silicide film containing only Pd_2Si phase. The most severe effect on the silicidation reaction, that is the increase in defect formation, was brought about by As predoping. The work function of the Pd_2Si FUSI gate was modulated by impurity pileup at the Pd_2Si/SiO_2 interface, as in the case of the NiSi FUSI gate. However, the work function shifted in the opposite direction ...
We report a detailed augmented-plane-wave energy-band study and wave-function analysis of stoichiometric PdH which shows that, even though the Fermi surface of PdH is qualitatively similar to that of silver, the simple ''proton model'' is not valid. Instead, the screening of the proton in PdH is found to be larger than in an isolated H atom due, in part, to the formation of a H-Pd bonding band below the bottom of the d-band complex. This result, which is in qualitative agreement with Switendick's earlier calculation, is confirmed by ultraviolet photoemission experiments. A partial density-of-states (DOS) analysis in the energy range spanned by the six valence and conduction bands reveals the quantitative details of the bonding mechanism between the Pd and H constituents. At the Fermi energy, the high Pd d to H s DOS ratio approx. 10.3 is found to be far higher ...
Charge flow and valence/d-band behavior in ion-beam-mixed (IBM) Pd1-xAgx (x = 0.5-0.9) alloys have been studied by X-ray photoemission measurement of the valence bands and of core-level binding energy shifts and X-ray absorption near-edge structure. We correlated the observed Ag 3d5/2 core-level shifts in these IBM alloys, relative to the elemental Ag, with the White Line area changes at the Pd and Ag L3-edge to investigate the charge redistribution at the Ag site. The results indicate that there is a decrease in sp-like conduction electron and a negligible change in the number of d-electrons at the Ag site upon alloying. These results are in line with our previous results in which Pd gains d-charges and loses sp-type charges. This electron redistribution due to hybridization in the alloy leads small net charge transfer from the Ag site to the Pd site in accordance with electronegativity predictions. ...
The isomerization of neopentane has been investigated over the 0.76 wt% Pd/SiO{sub 2} catalyst. It is found that after high temperature reduction (HTR, at 873 K) the selectivity for isomerization is much higher than that after low temperature reduction (LTR, at 573 K). A variety of experiments, including kinetic, chemisorption (O{sub 2}, H{sub 2}, and CO), temperature-programmed desorption of H{sub 2}, and X-ray diffraction, showed that this selectivity enhancement cannot be interpreted in terms of H{sub 2} retention by catalyst. Instead, the formation of Pd-Si compound(s) (most probably Pd{sub 3}Si) during HTR seems immediately responsible for the catalytic behavior of HTR Pd/SiO{sub 2} catalysts. A mechanism is proposed for the Pd-SiO{sub 2} interaction in which Pd atoms (or ions) are incorporated into the silica support (via oxygen vacancies) and a new phase ...
Pd-Ag bimetallic catalysts, supported on gamma-Al2O3, have been evaluated as exhaust catalysts for methanol-fueled vehicles. Laboratory studies have shown that a 0.01% Pd-5% Ag catalyst has greater CO and CH3OH oxidation activity than either 0.01% Pd or 5% Ag catalysts alone. Moreover, Pd and Ag interact synergistically in the bimetallic catalyst to produce greater CO and CH3OH oxidation rates and lower yields of methanol partial oxidation products than expected from a mixture of the single-component catalysts. The Pd-Ag synergism results from Pd promoting the rate of O2 adsorption and reaction with CO and CH3OH on Ag. Rate enhancement by the bimetallic catalyst is greatest at short reactor residence times where the oxygen adsorption rate limits the overall reaction rate.
Aging is the most significant risk factor for a range of degenerative disease such as cardiovascular, neurodegenerative and metabolic disorders. While the cause of aging and its associated diseases...Full Text Available
Aging is a biological process that affects most cells, organisms and species. Human aging is associated with increased susceptibility to a variety of chronic diseases, including cardiovascular disease,...Full Text Available
Insulitis is considered the histopathological hallmark of type I diabetes. In the non-obese diabetic (NOD) mouse, diabetes has never been observed in the absence of insulitis. The in vivo detection of insulitis could be of relevance for early prediction of diabetes. As approximately 15% of islet-infiltrating lymphocytes express interleukin 2 receptors, the authors have labelled recombinant inter-leukin 2 with "1"2"3I and used this radiopharmaceutical to detect insulitis by gamma camera imaging. The authors studied 71 prediabetic NOD and 27 normal Balb/c mice. Labelled #alpha#-lactalbumin was used as the control protein. In the first set of experiments the tissue distribution of radiolabelled interleukin 2 in isolated organs from animals sacrificed at different time points was studied. Higher radioactivity was detected in the pancreas of NOD mice injected with labelled interleukin 2, as compared to NOD mice receiving labelled #alpha#-lactalbumin. In another set of ...
Objective: Solid pseudopapillary tumor of the pancreas (SPTP tumor) is a rare pancreatic neoplasm with low malignant potential, which usually affects female patients in the second or third decades of life. It is a non-functional, slow-growing neoplasm that very often reaches considerable size before the first symptoms appear. Symptomatology is frequently related to tumor size. Surgical excision is usually curative in most cases. Infrequently the tumor can appear in male patients or in aged women, which can make the diagnosis more difficult. Some patients develop liver metastases in the follow-up that can be resected. Our purpose is to review the radiological and pathological findings of SPTP with emphasis on these infrequent cases. Subjects and methods: The medical records and radiological findings of patients who underwent surgery for SPTP between 2000 and 2005 were retrospectively reviewed. Study eligibility required that patients had undergone surgical resection ...
Objective: Solid pseudopapillary tumor of the pancreas (SPTP tumor) is a rare pancreatic neoplasm with low malignant potential, which usually affects female patients in the second or third decades of life. It is a non-functional, slow-growing neoplasm that very often reaches considerable size before the first symptoms appear. Symptomatology is frequently related to tumor size. Surgical excision is usually curative in most cases. Infrequently the tumor can appear in male patients or in aged women, which can make the diagnosis more difficult. Some patients develop liver metastases in the follow-up that can be resected. Our purpose is to review the radiological and pathological findings of SPTP with emphasis on these infrequent cases. Subjects and methods: The medical records and radiological findings of patients who underwent surgery for SPTP between 2000 and 2005 were retrospectively reviewed. Study eligibility required that patients had undergone surgical resection ...
Substitution of various rare earths R within the class of R2PdSi3 single crystals with hexagonal AlB2-type crystallographic structure reveals the systematic dependence of anisotropic magnetic properties governed by the interplay of crystal-electric field effects and magnetic two-ion interactions. Here we compare the floating zone (FZ) crystal growth with radiation heating of compounds with R = Tb, Tm, Pr, and Gd. The congruent melting behavior enabled moderate growth velocities of 3 to 5 mmh-1. The preferred growth directions are close to the basal plane of the hexagonal unit cell. The composition of the crystals, except of Tb2PdSi3, is slightly Pd-depleted with respect to the nominal composition 16.7 at.% Pd. Thin precipitates of RSi secondary phases were detected in the crystal matrix. Their phase fraction can be diminished by growth from Pd-rich melt compositions and annealing ...
Phase relations in the ternary system Ce-Pd-Si have been established for the isothermal section at 800 deg. C based on X-ray powder diffraction and EMPA techniques on about 130 alloys, which were prepared by arc-melting under argon or powder reaction sintering. Eighteen ternary compounds have been observed to participate in the phase equilibria at 800 deg. C. Atom order was determined by direct methods from X-ray single-crystal counter data for the crystal structures of #tau#_8-Ce_3Pd_4Si_4 (U_3Ni_4Si_4-type, Immm; a=0.41618(1), b=0.42640(1), c=2.45744(7) nm), #tau#_1_6-Ce_2Pd_1_4Si (own structure type, P4/nmm; a=0.88832(2), c=0.69600(2) nm) and also for #tau#_1_8-CePd_1_-_xSi_x (x=0.07; FeB-type, Pnma; a=0.74422(5), b=0.45548(3), c=0.58569(4) nm). Rietveld refinements established the atom arrangement in the structures of #tau#_5-Ce_3PdSi_3 (Ba_3Al_2Ge_2-type, Immm; a=0.41207(1), ...
Monogenic autoinflammatory diseases encompass a distinct and growing clinical entity of multisystem inflammatory diseases with known genetic defects in the innate immune system. The diseases...Full Text Available
Heart disease, cancer, and cerebrovascular disease together cause more than two out of three deaths in the United States annually. These three diseases are largely a result of widespread risk factors...Full Text Available
The molar extinction coefficients at the absorption maximum of the solvated electron spectrum have been evaluated to be 900, 970, and 1000 mol-1?m2 for 1,2-ethanediol (12ED), 1,2-propanediol (12PD), and 1,3-propanediol (13PD), respectively. These values are two-third or three-fourth of the value usually reported in the published report. Picosecond pulse radiolysis studies have aided in depicting the radiolytic yield of the solvated electron in these solvents as a function of time from picosecond to microsecond. The radiolytic yield in these viscous solvents is found to be strongly different from that of the water solution. The temperature dependent absorption spectra of the solvated electron in 12ED, 12PD, and 13PD have been also investigated. In all the three solvents, the optical spectra shift to the red with increasing temperature. While the shape of the spectra does not change in ...
The reactions between (100) GaAs and the near-noble metals Ni, Pd, and Pt have been investigated by application of high-resolution transmission electron microscopy (TEM), energy-dispersive analysis of x rays in the scanning TEM and Rutherford backscattering spectrometry. Emphasis is placed on the evolution of the phase distributions, film compositions, and interface morphologies during annealing at temperatures up to 480 /sup 0/C. The first phase in the Ni/GaAs reaction is shown to have the nominal composition Ni/sub 3/GaAs. Ternary phases of the type Pd/sub x/GaAs are also found to be the dominant products of the Pd/GaAs reaction. Conversely, only binary phases result from the Pt/GaAs reaction. These observations are used to construct isothermal sections of the M--Ga--As thin-film phase diagrams. The behavior of a thin (1--2 nm) native oxide--hydrocarbon layer during the Ni/GaAs, Pd/GaAs, and Pt/GaAs ...
The aim of this paper is to present and evaluate control strategies for adjustment and preservation of air quality, thermal and visual comfort for buildings' occupants while, simultaneously, energy consumption reduction is achieved. Fuzzy PID, fuzzy PD and adaptive fuzzy PD control methods are applied. The inputs to any controller are: the PMV index affecting thermal comfort, the CO{sub 2} concentration affecting indoor air quality and the illuminance level affecting visual comfort. The adaptive fuzzy PD controller adapts the inputs and outputs scaling factors and is based on a second order reference model. More specifically, the scaling factors are modified according to a sigmoid type function, in such a way that the measured variable to be as closer as possible to the reference model. The adaptive fuzzy PD controller is compared to a non-adaptive fuzzy PD and to an ON-OFF ...
...Advances in Chronic Kidney Disease-The purpose of Advances Chronic Kidney Disease is to provide in-depth, scholarly review articles about the care and mana ... Advances in Chronic Kidney Disease - Elsevier Home Products User Resources About Us Support & Contact Elsevier Websites Advanced Product ...Search Browse Journals Advances in Chronic Kidney Disease Advances in Chronic Kidney Disease Additional Information Related Publications Editorial Board Journal Online e- Alert Readers ...year: 6 Tips Title This is my tip content Visit Advances in Chronic Kidney Disease Online! The purpose of Advances Chronic Kidney Disease is ...
Single-crystalline CeRh_2Si_2 and CePd_2Si_2 were grown by the Czochralsky pulling method and the temperature dependence of magnetic susceptibility was investigated. The crystalline electric field (CEF) states in each compound were determined by considering the tetragonal CEF Hamiltonian with mean-field approximation. Interactions between Ce"3"+ ion and the surrounding ligands in CeRh_2Si_2 turned out to be strong and highly anisotropic in comparison to CePd_2Si_2. (orig.)
The damage induced by low-temperature proton irradiation in amorphous Pd/sub 80/Si/sub 20/ prepared by ion implantation is studied via electrical resistivity measurements. Our experimental results concerning the initial damage rate and the resistivity saturation are compared to the results obtained for electron and high energy /sup 16/O irradiation of amorphous Pd/sub 80/Si/sub 20/ quenched from the melt. The resistivity curve is analyzed in terms of irradiation-induced point defects.
The transformation of Pd/Si to Pd{sub 2}Si/Si is investigated using depth-resolved positron annihilation, x-ray diffraction and Auger electron spectroscopy studies. The observed defect-sensitive positron S-parameter value of 1.022-1.054 indicates the existence of divacancies across the silicide/silicon interface and Si substrate region. Our experimental observation of vacancy defects is consistent with the model proposed for excess vacancy generation across the interface consequent to Si diffusion. (letter to the editor)
An experimental verification for long-term performance of a Pd-Ag permeation in ITER tritium fusion cleanup units (FCU) is needed. In addition, information is required on the influence of tritium and {sup 3}He decay on the physical and chemical properties of Pd-Ag alloys (V-1). The results of the investigations of alloys (V-1) (mechanical properties and microstructure) after long-term usage exposition in tritium are given in this report. The experimental conditions (temperature, pressure, clearance, {sup 3}He concentrations) and the previous conclusions on the V-1 alloy performance are presented. (orig.).
The results of the second phase of the program of developing low cost contacts to silicon solar cells using copper are presented. Phase 1 yielded the development of a plated Pd-Cr-Cu contact system. This process produced cells with shunting problems when they were heated to 400 C for 5 minutes. Means of stopping the identified copper diffusion which caused the shunting were investigated. A contact heat treatment study was conducted with Pd-Ag, Ci-Ag, Pd-Cu, Cu-Cr, and Ci-Ni-Cu. Nickel is shown to be an effective diffusion barrier to copper.
Ab initio total-energy calculations, based on the exact muffin-tin orbital method, are used to determine the elastic properties of Pd1-xAgx random alloys in the face-centered-cubic crystallographic phase. The compositional disorder is treated within the coherent-potential approximation. The single crystal and polycrystalline elastic constants and the Debye temperature are calculated for the whole range of concentration, 0?x?1. It is shown that the variation in the elastic parameters of Pd-Ag alloys with chemical composition strongly deviates from a simple linear or parabolic trend. The complex electronic origin of these anomalies is demonstrated.
The variation of surface composition and sintering of the binary Pd{sub 7}Ag{sub 3} nanoparticles prepared by chemical reduction were studied. The composition of the as-prepared Pd{sub 7}Ag{sub 3} nanoparticles across the diameter is inhomogeneous due to different reduction potentials of Pd and Ag. Upon heating, Ag will migrate to the surface because of its lower surface energy. Surface modification results in variation of surface composition during the sintering process. Stearic acid acts as a grain growth inhibitor. The migration of Ag to the surface is suppressed and the sintering is retarded. Modification by polyethylene glycol leads to more migration of Ag atoms from the core to the surface. This makes the nanoparticles easier to sinter.
The variation of surface composition and sintering of the binary Pd_7Ag_3 nanoparticles prepared by chemical reduction were studied. The composition of the as-prepared Pd_7Ag_3 nanoparticles across the diameter is inhomogeneous due to different reduction potentials of Pd and Ag. Upon heating, Ag will migrate to the surface because of its lower surface energy. Surface modification results in variation of surface composition during the sintering process. Stearic acid acts as a grain growth inhibitor. The migration of Ag to the surface is suppressed and the sintering is retarded. Modification by polyethylene glycol leads to more migration of Ag atoms from the core to the surface. This makes the nanoparticles easier to sinter.
The ternary zirconium palladium silicide ZrPd{sub 3}Si{sub 3} has been synthesized by arc-melting of the elemental components. It adopts a new structure type and crystallizes in the orthorhombic space group Cmcm with a = 3.8127(4){angstrom}, b = 15.551(1){angstrom}, c = 7.0390(5){angstrom}, and Z = 4 (Pearson symbol oC28). The structure can be regarded as being built up of Re{sub 3}B-type slabs of composition Pd{sub 3}Si alternating with {alpha}-FeSi{sub 2} slabs of composition ZrSi{sub 2}. Notable features include the presence of Si{sub 2} pairs, square pyramidal and tetrahedral coordination of Pd centers by Si atoms, an unusual distorted cubic coordination of the Zr atoms by the Si{sub 2} pairs, and an extensive network of Zr-Zr, Zr-Pd, and Pd-Pd metal-metal bonds. ZrPd{sub 3}Si{sub 3} is weakly metallic with a room-temperature resistivity of 1.7 x 10{sup ...
indications of the formation of palladium silicides. 2, 4. It has been reported .... At room temperature, palladium silicides formed in a relatively narrow interface ...
The growth of thin Pd[sub 2]Si films on Si(111) surfaces is studied using [ital in] [ital situ] transmission electron microscope under ultrahigh vacuum conditions. No immediate reaction of deposited Pd with Si is observed at room temperature. At [similar to]200 [degree]C, uniform Pd[sub 2]Si films can be formed. The thin Pd[sub 2]Si films are found to grow into strained islands at elevated temperatures. Interfacial misfit dislocations associated with interfacial steps propagate across the strained islands, causing the islands to grow layer-by-layer at the interface. The strain fields associated with the misfit dislocations are believed to be responsible for this behavior.
Neutron diffraction and magnetometric measurements on polycrystalline samples of DyPd_2Si_2 and ErPd_2Si_2 were carried out in the temperature range from 2 to 293 K. Both compounds show tetragonal ThCr_2Si_2 type crystal structure and order at 12 K in a sine modulated magnetic structure with propagation vectors k=[0.609,0,0.155] and [0.575, 0, 0.083] respectively. The oscillatory character of magnetic order found in RPd_2Si_2 (R=Tb-Er) compounds suggests exchange interaction described by the RKKY model to be dominant, but the non-monotonic dependence of respective Neel temperatures on the number of f-electrons indicates the influence of a crystalline electric field (CEF) on the magnetic behaviour in this series. (orig.).
The effect of varying pD(11-13,7) on the reaction of hydrogen with (Co/sup 11/(CN)/sub 5/)/sup 3/- in deuterium oxide has been studied by using infrared spectroscopy to determine the ratio of (Co/sup 111/(CN)/sub 5/X)/sup 3/- (X=H,D) in the solids precipitated from the steady state under hydrogen. The results show that the uptake of hydrogen does not liberate a free proton and that the rate of (Co/sup 111/(CN)/sub 5/H)/sup 3/- -D/sub 2/,0 exchange increases with pD but becomes pD independent at pD 7 greater than 13,5.
The x-ray diffraction technique described previously for measurement of growth kinetics of Pd/sub 2/Si layers from their solid state reaction couples has been extended by the use of a one-dimensional position-sensitive detector (PSD). Additionally, the method has been extended to include measurement of the Pd layer. A detailed description of the experimental arrangement and analytical procedures is presented. The kinetics of epitaxial Pd/sub 2/Si film growth were measured in situ over a range of 170--230 /sup 0/C. The PSD results, using data obtained from both the Pd/sub 2/Si and Pd layers, were able to confirm parabolic growth behavior for the Pd/sub 2/Si film. The rate constants followed Arrhenius behavior and yielded an activation energy of E = 1.32 +- 0.07 eV with a prefactor k/sub 0/ = 0.49 cm/sup 2//s for the Pd/sub 2/Si layer analysis ...
The evolution of strain in the Pd-Si system during the growth of Pd{sub 2}Si thin films on Si (100) substrate has been followed in situ using a double optical beam technique. As was observed for the Pt-Si system, the reaction to form Pd{sub 2}Si yields a compressive intrinsic surface film stress as well as for the silicon-rich suicides as proposed by Angilello et al. [Thin Film Interfaces and Interactions, edited by J. Baglin and J. Poate (The Electrochemical Society, Pennington, NJ, 1980)]. A transmission electron microscopy analysis has revealed grain growth during the formation of Pd{sub 2}Si which cannot account for the compressive film stresses. The formation of silicide at the interfaces rather than the overall change in volume agrees with the sign of the stresses formed. 29 refs., 4 figs., 3 tabs.
Stability and decomposition of PtSi, NiSi, and PdSi in contact with single crystal or amorphous Si is examined. PtSi, PdSi and NiSi are thermally stable both with Si, but are unstable in contact with metal film. It is shown that epitaxial Si layers can be obtained using both Pd and Al as metal film and layers can be electrically doped by the addition of a doping layer to the thin film structure prior to the heat treatment or by inclusion of Al atoms so that n/sup +/ and p/sup +/ conductivity can be achieved in the grown epilayer. The effects of impurities, substrate orientation on the growth kinetics are also discussed. (LEW)
High-field magnetization properties of single crystalline CeRh{sub 2}Si{sub 2} and CePd{sub 2}Si{sub 2} were investigated. Two-step metamagnetic transition (H{sub c1}=25.4 T and H{sub c2}=26.0 T) was observed in the case of CeRh{sub 2}Si{sub 2}, whereas no anomaly was found in the magnetization process of CePd{sub 2}Si{sub 2} up to 28 T. The mean field analysis has shown that CeRh{sub 2}Si{sub 2} is quite anisotropic compared to CePd{sub 2}Si{sub 2}, which results in the sharp contrast between the magnetization processes of the two compounds.
High-field magnetization properties of single crystalline CeRh_2Si_2 and CePd_2Si_2 were investigated. Two-step metamagnetic transition (H_c_1=25.4 T and H_c_2=26.0 T) was observed in the case of CeRh_2Si_2, whereas no anomaly was found in the magnetization process of CePd_2Si_2 up to 28 T. The mean field analysis has shown that CeRh_2Si_2 is quite anisotropic compared to CePd_2Si_2, which results in the sharp contrast between the magnetization processes of the two compounds
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Palladium chloride films have been found to be useful as ... when suitably prepared palladium chlo- ride films are exposed ... Like the palladium chloride ( PdCl2) ...
Pd/sub 2/Si formation at the Pd-Si interface induced by irradiation with ions having a wide range of nuclear energy of deposition density has been investigated. It is found that the thickness of the silicide layer formed by irradiation is proportional to the ion fluence for irradiation with ions having low energy-deposition densities, while it is proportional to the square root of the fluence for irradiation with ions having energy-deposition densities. The results indicate that Pd/sub 2/Si formation is reaction limited when the energy-deposition density at the interface is low and is diffusion limited when it is high. The results are compared with the phenomenological theory developed by Horino et al. and it is shown that such a dependence of the limiting processes on the energy depositon density is induced when the diffusion is thermally activated while the reaction at the interface is radiation-enhanced.
We report studies of bimetallic nanoparticles with 15%-16% atomic crystal parameters size mismatch. The degree of alloying was probed in a 2-nm Pt core (smallest attainable core size) of Pt-Ag nanoparticles (completely immiscible in bulk) and 20-nm-diameter Pd-Ag nanowires (completely miscible in bulk). Particles were synthesized radiolytically, and depending on the initial parameters, they assume spherical or cylindrical (nanowire) morphologies. In all cases, the metals are seen to follow their bulk alloying characteristics. Pt and Ag segregate in both spherical and wire forms, which indicates that strain due to crystallographic mismatch overcomes the excess surface free energy in the small particles. The Pd-Ag nanowires alloy similar to previously reported spherical Pd-Ag particles of similar diameter and composition.
The compounds CePdSi_2, CeIrSi_2 and CeRhSn_2 have been synthesized and studied by X-ray diffraction, electrical resistivity and magnetic susceptibility. The magnetic susceptibility of CePdSi_2 exhibits two peaks at 6.8 K and 2.5 K, respectively, indicating two antiferromagnetic phase transitions, while that of CeIrSi_2 shows a broad maximum at 150 K, characteristic of valence fluctuating Ce-compounds. CeRhSn_2 remains paramagnetic down to 5 K. The resistivity of CeIrSi_2 exhibits a T"2 dependence at low temperatures, indicating a Fermi-liquid ground state, while those of CePdSi_2 and CeRhSn_2 shows the presence of Kondo and crystal field effects. (orig.).
Different semi precious alloys (Pd-Ag, Pd-Au) have been studied after thermal oxidation treatments to analyze the mechanical improvement of the interface between the metal and the ceramic. Using the four point bending test, the authors have analyzed the different steps corresponding to the mechanical evolution of the bi-material : cracking energy on the surface, relaxation energy after first cracking, propagation energy of cracks at the interface zone. It has been shown that some alloys only have a high resistance to the interface cracking and the role played by the interface reactions to improve this property. (orig.).
into the SiC interface to form of palladium silicides (PdSix) and the subsequent migration of elemental silicon to the surface from the SiC. Palladium silicides are ...
The formation and properties of Pd{sub 2}Si formed by focused ion beam implantation of Pd ions into Si is presented in this thesis. An extensive microstructural study using transmission electron microscopy was undertaken and the as-implanted as well as annealed microstructure is shown. Results of other analysis techniques such as Rutherford back scattering and secondary ion mass spectrometry etc. are also presented. Kinetic information on the growth of Pd{sub 2}Si obtained by both microstructural and resistance measurements indicates that the activation energy for growth of the silicide is around 0.36 to 0.39 eV. This can be compared with the normally reported value of 1.5 eV for Pd{sub 2}Si formed by annealing thin film Pd on Si. The growth of the silicide was found to follow t{sup 1/2} kinetics. Microstructural observation of the as-implanted samples showed extensive in-situ ...
The formation and properties of Pd_2Si formed by focused ion beam implantation of Pd ions into Si is presented in this thesis. An extensive microstructural study using transmission electron microscopy was undertaken and the as-implanted as well as annealed microstructure is shown. Results of other analysis techniques such as Rutherford back scattering and secondary ion mass spectrometry etc. are also presented. Kinetic information on the growth of Pd_2Si obtained by both microstructural and resistance measurements indicates that the activation energy for growth of the silicide is around 0.36 to 0.39 eV. This can be compared with the normally reported value of 1.5 eV for Pd_2Si formed by annealing thin film Pd on Si. The growth of the silicide was found to follow t"1"/"2 kinetics. Microstructural observation of the as-implanted samples showed extensive in-situ formation of ...
The applicability of Pd/sub x/Ta/sub 1-x/ as a diffusion barrier on Si has been investigated. For this purpose Pd/sub x/Ta/sub 1-x/ films of 200 nm thickness (x ranges from 0 to 1) were deposited on Si(100), and the reaction between over-layer and substrate was studied as a function of temperature. Interaction was found to occur at temperatures increasing with the Ta content. The as-deposited Pd/sub x/Ta/sub 1-x/ films with 0.2 less than or equal to x less than or equal to 0.6 were found to be amorphous. The amorphous phase had a higher reaction temperature than the crystalline one, causing a discontinuous step in the reaction temperature. RBS spectra revealed that for the Pd-rich compositions first a stoichiometric Pd2Si layer formed underneath a pure Ta layer. At higher temperatures TaSi2 formed at the surface. For Ta-rich compositions Pd2Si formed first as ...
Palladium silicides (Pd(x)Si) formed at a broadened interface after annealing, but a significant layer of alloy film is still free of silicon and carbon. ...
In YbPd_2Si_2, the valence of Yb is very close to 3+. Ge substitution of Si induces a negative pressure effect and the valence of Yb decreases. For the low Ge concentrations studied, the spin fluctuation temperature T_s_f increases and #chi#4f, the Yb derived 4f susceptibility, obeys the scaling law #chi#4f(T)=F(T/T_s_f). (orig.).
The Si L/sub 2/ /sub 3/VV Auger Lineshape for Pd/sub 4/Si was measured and found to be in good agreement with the self-fold of the Si partial density of states model calculated by Riley et al. Oxygen chemisorption altered both the Auger lineshape and the HeI photoemission spectrum, especially near the Fermi energy.
The recovery of noble metals from the quaternary Mo-Ru-Rh-Pd alloy in the simulated insoluble residue was studied by means of Pb extraction and the recovery yield was found to be more than 90% for Ru, Rh and Pd. The recovery yield of Mo was very small due to the oxidative vaporization in air. The decontamination factor for Ce as a stand-in of Pu was determined to be around 200 for one stage. These results on the recovery yields of noble metals from the quaternary alloy and the decontamination factor for Ce are in good agreement with those for the ternary Mo-Ru-Pd alloy previously reported by the present authors. The mutual separation of noble metal elements recovered in Pb button was examined by means of re-extraction with molten Zn and the dissolution in boiling 3M or 6M nitric acid solution. The dissolution fractions of Pd and Rh recovered in the Pb button in boiling 3M and 6M nitric acid solution for ...
The possibilities and problems of PCA in phase separation are shown on Ni, Pd, and Pt silicides. The PCA depth profiles are less influenced by sputter and matrix effects than usual Auger depth profiles. The position of the silicide-Si interface is well defined by the component distribution crossover in PCA profiles. An interface component between Pd and Pt silicides and Si substrate is determined by PCA.
The possibilities and problems of PCA in phase separation are shown on Ni, Pd, and Pt silicides. The PCA depth profiles are less influenced by sputter and matrix effects than usual Auger depth profiles. The position of the silicide-Si interface is well defined by the component distribution crossover in PCA profiles. An interface component between Pd and Pt silicides and Si substrate is determined by PCA. (author).
The achievement of inner-shell photoionization of Zn-like Pd by means of two exploding foils is described. This resulted in the soft X-ray transition 3d94s2-3d104p at 46 A. It is shown that the photoionization of inner shell electrons in highly stripped ions can lead to X-ray transitions which may be candidates for X-ray lasers under 50 A.
Radioactive "3"1Si(Tsub(1/2) = 2.62 h) and Rutherford backscattering were used to study Ni_2Si, Pd_2Si and Pt_2Si formation, silicon self-diffusion in silicides and silicon epitaxy in the Si(100)/Pd_2Si/Si (amorphous) system. (Auth.).
The magnetic excitations of the Kondo compound CePd_2Si_2 below its Neel temperature (T_N = 10 K) have been studied by inelastic neutron scattering. At T = 1.6 K the data are best represented by two dispersive inelastic modes. Their linewidth (#propor to# 0.5 meV) indicates substantial broadening, which is ascribed to Kondo-type local fluctuations. (orig.).
We report on solid solution CePd_2_-_xMn_xSi_2 which shows an interesting transition of the Ce-ion from magnetism in a Kondo regime to an intermediate valence state coupled with a strongly magnetic 3d sublattice. ((orig.)).
We report on solid solution CePd[sub 2-x]Mn[sub x]Si[sub 2] which shows an interesting transition of the Ce-ion from magnetism in a Kondo regime to an intermediate valence state coupled with a strongly magnetic 3d sublattice. ((orig.))
Experimental data in the Kondo lattice YbPd_2Si_2 is compared with the results of a hybridization model, based ont he 'large degeneracy expansion' approximation, which takes into account the crystal field level splittings of the Yb ion. We show that satisfactory agreement is obtained with a unique set of crystal field and hybridization parameters. (orig.).
Experimental data in the Kondo lattice YbPd{sub 2}Si{sub 2} is compared with the results of a hybridization model, based ont he 'large degeneracy expansion' approximation, which takes into account the crystal field level splittings of the Yb ion. We show that satisfactory agreement is obtained with a unique set of crystal field and hybridization parameters. (orig.).
We report resistivity and thermopower measurements of the heavy fermion compound CePd{sub 2}Si{sub 2} at pressures up to 56 kbar. At pressures from 21 to 34.5 kbar, we measured the resistivity down to 30 mK, for all other pressure steps the temperature range was 1.2-300 K. (orig.).
We report resistivity and thermopower measurements of the heavy fermion compound CePd_2Si_2 at pressures up to 56 kbar. At pressures from 21 to 34.5 kbar, we measured the resistivity down to 30 mK, for all other pressure steps the temperature range was 1.2-300 K. (orig.).
Single crystals of U(Ni_1_-_xPd_x )_2Si_2 for x = 0.05, 0.10 and 0.15 have been grown. Magnetization and electrical resistivity measurements were performed in a wide range of temperatures, magnetic fields and high pressures in order to study stability of magnetic phases in the solid solutions between UNi_2Si_2 and UPd_2Si_2 with a special emphasis on the type of ground state. In UPd_2Si_2 the simple AFI-type antiferromagnetic structure of U moments is observed at low temperatures. UNi_2Si_2 adopts the uncompensated AF structure (UAF) with the ++- stacking of U moments along the c-axis and consequently this compound exhibits a spontaneous magnetization corresponding to 1/3 of the U moment. The substitution of Pd for Ni leads to a rapid decay of the spontaneous magnetization. The evolution of magnetization and electrical resistivity behavior with Pd doping is tentatively attributed to the coexistence of the AF-I and UAF ...
Density changes in amorphous Pd{sub 80}Si{sub 20} during ion irradiation below 100K were detected by in situ HVEM measurements of the changes in specimen length as a function of ion fluence. A decrease in mass density as a function of the ion fluence was observed. The saturation value of the change in mass density was determined to be approximately -1.2%.
The surface of Si and thin layers of Pd{sub 2}Si on Si have been studied by low-energy He{sup +} ion scattering. The occurrence of the observed low-energy tails is attributed to reionization at the surface of He neutrals scattered from subsurface layers. It is shown that the tails provide in-depth information. (orig.).
Plasma-deposited thin films prepared at room temperature, ranging from 46 to 250 A of PdAu on #approx#45-50 A Si-oxide and Si-oxynitride films grown on Si wafers were studied. Grazing incidence X-ray diffraction, X-ray reflectivity, and XPS depth profile techniques were used to characterize the thin films. A reactive interface involving Pd- and Au-silicides is formed, linking the thin film to the Si-oxide and Si-oxynitride films: a small fraction of Pd and Au atoms from PdAu migrate into the Si substrate, first penetrating the oxide layer, and the small fraction of Si atoms from the oxide layer migrate into the PdAu film and form a silicide interlayer consisting of a reactive interface made up of mixtures of Au- and Pd-silicides interspersed within the matrix of PdAu and substrate. The concentration profiles of these silicides have a maximum ...
Cerium [ital L][sub 3] XANES (x-ray-absorption near-edge-structure) spectra were analyzed to separate Ce moment contributions and mixed valence (MV) in complex magnetic silicides CePd[sub 2[minus][ital x
This paper describes the anelastic strain recovery and the strain hardening of amorphous metals and presents the experimental result that creep deformation is represented by a viscoelastic model consisting of rheological elements. Materials studied were 80Pd--20Si, 80Fe--13P--7C, and 60 Cu--40 Zr. (DLC)
The reaction of ethanol on unreduced and H{sub 2}-reduced CeO{sub 2} and 1 wt% Pd/CeO{sub 2} has been investigated by steady state reactions, temperature programmed desorption (TPD), and in situ Fourier transform infrared (FT-IR) spectroscopy. Steady state reactions have shown a zero reaction order dependency for diatomic oxygen at and above 20%, while the addition of Pd to CeO{sub 2} decreases the apparent activation energy of the reaction from 75 kJ/mol on CeO{sub 2} alone to 40 kJ/mol (Pd/CeO{sub 2}). TPD experiments following ethanol adsorption on both CeO{sub 2} and Pd/CeO{sub 2} have shown desorption profiles corresponding to unreacted ethanol and various reaction and decomposition products (acetaldehyde, acetone, CO, CO{sub 2}, and methane). Ethanol conversion to reaction products was increased by the addition of Pd, from 15 to 30% on CeO{sub 2} and H{sub 2}-reduced CeO{sub ...
Primary malignant lymphoma of the brain is a disease of unknown etiology, which is increasing in incidence and has an unfavorable prognosis. Despite the lack of specific changes on CT or MRI in most cases, these procedures may typically facilitate the diagnosis: A focal-enhancing mass with subependymal spread on CT or MRI and hyperattenuation on nonenhanced CT are the most reliable features in the diagnosis of primary malignant lymphoma of the brain. Peritumoral edema and mass effect are usually not prominent features. On unenhanced CT scans they usually appear homogeneously isodense to mildly hyperdense relative to the gray matter. On MRI these tumors are slightly hypointense on T1-weighted images and slightly hpyerintense on PD- and T2-weighted images relative to the gray matter. On CT and MRI enhancement is usually homogeneous. Contrast-enhanced MRI, with its multiplanar capability, lack of bone-induced artifacts, and high-contrast ...
Alkaline fuel cells (AFCs) provide a less corrosive environment and can provide higher electrode reaction kinetics than proton exchange membrane fuel cells (PEMFCs). The alkaline media also allows for the replacement of platinum (Pt) based electrocatalysts with non-Pt electrocatalysts. Studies have shown that palladium (Pd) and silver (Ag) form a homogenous solid solution with a face-centred cubic structure within a large range of temperatures. This study described the results of an oxygen reduction reaction (ORR) on lead-silver (Pd-Ag) alloy electrodes in alkaline media. The reaction was compared with Pd and Ag electrodes. The alloys were synthesized as thin films using a sequential electroless deposition of Pd and Ag on stainless steel discs followed by an annealing procedure in an Ar stream. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used ...
The changes in the electrical and structural properties of metal-silicide films caused by ion implantation and subsequent thermal annealing have been investigated. Epitaxial silicide films such as those of CoSi/sub 2/, NiSi/sub 2/ and Pd/sub 2/Si grown on Si(111) substrates were implanted with Ar ions and annealed in a vacuum furnace at temperatures ranging from 200 to 800/sup 0/C. Rutherford backscattering and channeling techniques and the four-point probe method were used to measure the crystalline quality and the sheet resistance of the films, respectively. It was found that the sheet resistances of CoSi/sub 2/, NiSi/sub 2/ and Pd/sub 2/Si films were increased by factors of 70, 6, and 3, respectively, by implantation to a dose of 1 x 10/sup 16/ Ar-ions/cm/sup 2/, but that they were almost restored by subsequent annealing to the values before implantation. A phase transformation from Pd/sub 2/Si to ...
The changes in the electrical and structural properties of metal-silicide films caused byion implantation and subsequent thermal annealing have been investigated. Epitaxial silicide films such as those of CoSi"2, NiSi"2 and Pd"2Si grown on Si(111) substrates were implanted with Ar ions and annealed in a vacuum furnace at temperatures ranging from 200 to 800_0C. Rutherford backscattering and channeling techniques and the four-point probe method were used to measure the crystalline quality and the sheet resistance of the films, respectively. It was found that the sheet resistances of CoSi"2, NiSi"2 and Pd"2Si films were increased by factors of 70, 6, and 3, respectively, by implantation to a dose of 1 x 10_1_6 Ar-ions/cm_2, but that they were almost restored by subsequent annealing to the values before implantation. A phase transformation from Pd"2Si to PdSi was also observed in the high-temperature ...
The 1H NMR, electronic absorption, and luminescence spectra, as well as voltammograms of the reduction and oxidation of the complexes [Pd(C?N)(N?N)]ClO4 and [Pd(C?N)(?-OOCCH3)]2 [where (C?N)? is deprotonated 2-phenyl-4,5-dihydro-1,3-oxazole, and N?N is ethylenediamine or 2,2?-bipyridine (bpy)] were compared. Magnetic nonequivalence of protons in the dihydrooxazole ring and upfield shift of the corresponding signals were observed as a result of anisotropic effect of the ring current in palladated phenyl substituents in the [Pd(C?N)(?-OOCCH3)]2 complex having a C 2 symmetry. One-electron reduction wave of [Pd(C?N)bpy]+ was assigned to ligand-centered electron transfer to the ?* orbital of 2,2?-bipyridine, and two oxidation waves of [Pd(C?N)(?-OOCCH3)]2 were attributed to successive one-elect...
A simple one-step method to fabricate hierarchically porous TiO2/Pd composite hollow spheres without any template was developed by using solvothermal treatment. Pd nanoparticles (2-5 nm) were well dispersed in the mesopores of the TiO2 hollow spheres via in-situ reduction. In our experiment, polyvinylpyrrolidone played an important role in the synthetic process as the reducing agent and the connective material between TiO2 and Pd nanoparticles. HF species generated from solvothermal reaction leaded to the formation of TiO2 hollow spheres and Ostwald ripening was another main factor that affected the size and structure of the hollow spheres. The as-prepared TiO2/Pd composite hollow spheres exhibited high electrocatalytic activity towards the reduction of H2O2. The sensitivity was about 226.72 ?A mM-1 cm-2 with a detection limit of 3.81 ?M at a signal-to-noise ratio of 3. These results made the ...
This study provides a comprehensive description of the main morphological and histological events that take place during larval and post-larval development of Senegal sole Solea senegalensis in order to establish a reference for its normal developmental organogenesis. Five stages have been described. Before gill development at the onset of metamorphosis (eye migration process, stage 4c), the skin was the main site of gas and ion exchange, whereas during stages 3 and 4, the skin begins differentiating into the definitive juvenile structure. The timing of development of the endocrine system depends on each organ, the endocrine pancreas and thyroid gland being the first to differentiate (stages 2 and 3, respectively), followed by the interrenal tissue and stannius corpuscles that develop at m...
The authors have cloned a full-length putative rat pancreatic lysophospholipase cDNA by an improved mRNA isolation method and cDNA cloning strategy using (/sup 32/P)-labelled nucleotides. These new methods allow the construction of a cDNA library from the adult rat pancreas in which the majority of recombinant clones contained complete sequences for the corresponding mRNAs. A previously recognized but unidentified long and relatively rare cDNA clone containing the entire sequence from the cap site at the 5' end to the poly(A) tail at the 3' end of the mRNA was isolated by single-step screening of the library. The size, amino acid composition, and the activity of the protein expressed in heterologous cells strongly suggest this mRNA codes for lysophospholipase.
The European sea bass Dicentrarchus labrax is a marine teleost important in Mediterranean aquaculture. The development of the entire digestive tract of D. labrax, including the pharynx, was investigated from early embryonic development to day 5 post hatching (dph), when the mouth opens. The digestive tract is initialized at stage 12 somites independently from two distinct infoldings of the endodermal sheet. In the pharyngeal region, the anterior infolding forms the pharynx and the first gill slits at stage 25 somites. The other three gill arches and slits are formed between 1 and 5 dph. Posteriorly, in the gut tube region, a posterior infolding forms the foregut, midgut and hindgut. The anus opens before hatching, at stage 28 somites. Associated organs (liver, pancreas and gall bladder) ar...
Nonfunctioning pancreatic endocrine tumors (PETs) are rare and generally asymptomatic. A 68-year-old woman who had refused treatment for a pancreatic mass, revealed by ultrasonography to be 55 mm in diameter, was referred to us again 29 months later with jaundice. Investigations showed an 82-mm tumor in the head of pancreas, exposed from the papilla of Vater to the duodenal lumen. After biliary decompression and drainage, we performed pancreatoduodenectomy with resection of the portal vein and superior mesenteric vein, followed by reconstruction using a cylindrically customized autologous graft harvested from the right ovarian vein. The tumor was resected curatively. Microscopically, it consisted of trabecular and ribbon-like arrangement of neoplastic cells. Immunohistochemical staining wa...
Glucose homeostasis requires the tight regulation of glucose utilization by liver, muscle and white or brown fat, and glucose production and release in the blood by liver. The major goal of maintaining glycemia at -5 mM is to ensure a sufficient flux of glucose to the brain, which depends mostly on this nutrient as a source of metabolic energy. This homeostatic process is controlled by hormones, mainly glucagon and insulin, and by autonomic nervous activities that control the metabolic state of liver, muscle and fat tissue but also the secretory activity of the endocrine pancreas. Activation or inhibition of the sympathetic or parasympathetic branches of the autonomic nervous systems are controlled by glucose-excited or glucose-inhibited neurons located at different anatomical sites, mainl...
Amphiphysin is a protein concentrated in neuronal synapses and peripherally associated with neurotransmitter vesicles. It is expressed in many neurons of the central and peripheral nervous systems, in the adrenal medulla, in the anterior and posterior pituitary, in cell lines of the endocrine pancreas, and in spermatocytes. Its subcellular localization and tissue distribution indicate a potential involvement in mechanisms of regulated exocytosis. A role in the dynamic organization of the membrane-associated cytoskeleton is suggested by structural homology to the products of two yeast genes, RVS161 and RVS167, whose mutation results in an abnormal actin distribution, disturbs budding morphology, and impairs cell entry into stationary phase. Limited stretches of sequence similarity, including an SH3 domain, are also shared with other actin-binding proteins. Amphiphysin is the dominant autoantigen in paraneoplastic Stiff-Man syndrome, a neurological autoimmune ...
The authors have studied the distribution of H-3 labelled schistosomicidal drug in mice by autoradiography. The H-3-labelled substances were found in liver and kidney and in successfully decreasing amounts in brain, lung, heart, fat, testis, pancreas and spleen. In various cells the silver granules were present mainly in the cytoplasms but a few in the nucleus. After administration of this labelled schistosomicidal drug, the mice were killed and studied in groups successively at 4, 8, 24 hrs. No difference in the distribution of silver granules were observed. This fact indicated that, this drug was rapidly absorbed and highly concentrated with a long duration of reservation in liver. All of these favours the schistosomicidal effect of the drug. As this drug was highly concentrated in the cytoplasm of liver cells, that might provide a pathophysiologic basis for the explanation of jaundice in the clinical practice. Moreover, the appearance of toxic reaction in ...
A tissue-equivalent dosimetry system has been developed for use in absorbed dose determinations with physical models of Reference Man. The dosimeter used was a thermo-luminescent dosimeter (TLD) powder which was mixed with a 'tissue-equivalent' material and modeled to closely approximate an organ's geometry and absorption properties. A separation procedure was developed by which the TLD powder was washed and the 'tissue-equivalent' material, a wax, was dissolved and extracted following the irradiation of the model. The procedure was tested to determine losses of powder, homogeneity of the powder's distribution throughout the wax, the effects of the separation procedure upon the powder and the statistical behavior of the procedure. The results of these tests established the feasibility of the procedure. A full-scale model of the pancreas was tested and the results supported the validity of the technique. (author)
Alzheimer's disease (AD) is the most common form of dementia in the elderly. Although traditionally considered a disease of neurofibrillary tangles and amyloid plaques, structural and functional changes...Full Text Available
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Cerebral atrophy rate is increasingly used as an outcome measure for Alzheimer's disease (AD) trials. We used the Alzheimer's disease Neuroimaging initiative (ADNI) dataset to assess if adjusting...Full Text Available
Objectives:Copy number variants (CNVs) have been recognized as a source of genetic variation that contributes to disease phenotypes. Alzheimer disease (AD) has high heritability...Full Text Available
Polycystic kidney disease (PKD) is one of the leading causes of end-stage renal disease in humans and is characterized by progressive cyst formation, renal enlargement, and abnormal tubular development....Full Text Available
Background/Aims:Inflammatory bowel disease (IBD) was previously thought a rare disease among children in Kuwait since most diarrhea cases were attributed to infections....Full Text Available
Infections have been implicated in the pathogenesis of a number of autoimmune diseases, and Yersinia enterocolitica (YE) might play a role in the development of autoimmune thyroid disease...Full Text Available
Forty-one Spanish families with polycystic kidney disease 1 (PKD1) were studied for evidence of linkage disequilibrium between the disease locus and six closely linked markers. Four of these loci--three...Full Text Available
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STUDY OBJECTIVE: To estimate the incidence rate of newly diagnosed cases of coeliac disease in Italy. DESIGN: This was a descriptive study of coeliac disease incidence in the period 1990-91. SETTING:...Full Text Available
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Chronic wasting disease (CWD) is a contagious, fatal prion disease of deer and elk that continues to emerge in new locations. To explore the means by which prions are transmitted with high efficiency...Full Text Available
One of the modifiable risk factors associated with coronary heart disease (CHD) is hypercholesterolemia. This paper reviews the major plasma lipids and how they relate to coronary heart disease. Among...Full Text Available
Chagas disease, caused by infection with Trypanosoma cruzi, is an important cause of cardiovascular disease. It is increasingly clear that parasite-derived prostaglandins potently modulate...Full Text Available
Enzootic Glassers's disease was investigated to study the epidemiology of the disease strains on a farm where it presented a problem. Restriction endonuclease fingerprinting (REF) analysis technique...Full Text Available
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Aberrant transglutaminase (TG) activity has been implicated in the pathology of numerous diseases including Huntington disease and Alzheimer disease. To fully characterize the role of TGs in...Full Text Available
The nine title compounds were prepared from the elements by arc-melting and subsequent heat treatment in resistance and high-frequency furnaces. The crystal structure of these isotypic compounds was determined for YPdSi from single-crystal X-ray diffractometer data: Pmmn, a = 430.8(1) pm, b = 1391.2(1) pm, c = 743.1(1) pm, Z = 8, R = 0.024 for 417 structure factors and 40 variable parameters. The crystal structures of the isotypic compounds GdPdSi and ErPdSi were also refined from single-crystal data. The structure is of a new type. It consists of condensed, six-membered rings of alternating palladium and silicon atoms with Pd-Si bond distances varying between 249.6 and 258.8 pm. These two-dimensionally infinite nets are connected to each other via weak Pd-Si and Si-Si bonds with bond distances of 276.3 and 259.5 pm. The rare earth atoms are situated above and below the six-membered palladium-silicon ...
The oxide colloidal route, developed in the laboratory for mono-metallic catalysts, consists in preparing a metallic oxide hydro-sol which leads to the supported catalyst after deposition onto a support and an activation stage. In this work, this method has been adapted to the preparation of alumina supported bimetallic Pd-Sn catalysts to determine its interest for the control of the properties of the bimetallic phase (size, composition and structure). In the preliminary study concerning tin oxide sols, SnO{sub 2} (size=2,3 nm) and Sn{sub 6}O{sub 4}(OH){sub 4} (size = 25 nm) nano-particles were synthesized by neutralization respectively for tin(IV) and tin(H). The control through the pH of the aggregation of the PdO and SnO{sub 2} particles revealed that increasing oxide solubility promotes integral re-dispersion of the oxide particles. To synthesize oxide bimetallic sols, three strategies were defined. Copolymerization (formation of a mixed ...
R_2PdSi_3 compounds have been found to exhibit rich magnetic phenomena arising from the interplay between RKKY interaction, crystal electric field effects and geometric frustration due to the derived hexagonal AlB_2 structure. The observed crystallographic superstructure further complicates the CEF level scheme. Inelastic neutron scattering measurements on single crystals of Tm_2PdSi_3 and Er_2PdSi_3 have been performed at the cold triple axis spectrometer PANDA in FRM-II. Both compounds order antiferromagnetically at T_N=7 K and 2.1 K respectively; Er_2PdSi_3 undergoes a second phase transition at T_2=2 K. Several low lying CEF excitations (below 10 meV) were observed. The intensity of the lowest excitation show strong directional dependence (in HK0 plane for Er_2PdSi_3 and in HHL plane for Tm_2PdSi_3), from which the details of the transitional matrix could be ...
...American Journal of Kidney Diseases-The American Journal of Kidney Diseases (AJKD), the official journal of the National Kidney Foundation, is ... American Journal of Kidney Diseases - Elsevier Home Products User Resources About Us Support & Contact Elsevier Websites Advanced Product ...Search Browse Journals American Journal of Kidney Diseases American Journal of Kidney Diseases Official Journal of the National Kidney Foundation Additional Information Related Publications ...Article Tracking for Editors Reviewers Advertisers/Sponsors Advertisers Media Kit Societies National Kidney Foundation ISSN: 0272-6386 Imprint: SAUNDERS Actions Submit ...
BackgroundIncrease in the incidence of hyperuricemia associated with gout as well as hypertension, renal diseases and cardiovascular diseases has been a public health concern. We...Full Text Available
Contagious diseases are a threat to animal health and productivity, both nationally and at the farm level. This makes implementation of biosecurity measures to prevent their introduction and...Full Text Available
Hypersensitivity Pneumonitis (HP) is an interstitial lung disease that develops following repeated exposure to inhaled environmental antigens. The disease is characterized by alveolitis, granuloma formation...Full Text Available
Hypophosphatasia is a congenital disease characterized by deficiency of serum and tissue non-specific alkaline phosphatase activity. The disease occurs due to mutations in the liver/bone/kidney alkaline...Full Text Available
BackgroundSeveral studies have suggested an association between periodontal disease and prematurity but this finding has not been consistently observed.MethodsCase...Full Text Available
Percutaneous renal biopsy (PRB) is a safe and effective tool in the diagnosis and management of renal disease. It is the gold standard for evaluating renal parenchymal disease. It is both useful for...Full Text Available
The identification of individuals at risk for Alzheimer's disease (AD) is essential for the timely administration of treatment approaches aimed at slowing the onset or progression of the disease....Full Text Available
Stabbing paroxysmal pain due to neurological disease can often be controlled by anticonvulsants, whereas steady burning pain is often responsive to tricyclic antidepressants, and to neuroleptics. Overuse...Full Text Available
Primary sclerosing cholangitis (PSC) is a rare cholestatic liver disease with major morbidity and mortality. Therapeutic management is difficult, due to lack of conclusive data and individual disease...Full Text Available
Rheumatoid arthritis (RA) is a debilitating autoimmune disease of global prevalence. The disease is characterized by synovial inflammation leading to cartilage and bone damage. Most of the conventional...Full Text Available
AIM: To search the independent factors determining gastric juice acidity and to investigate the acidity of gastric juices in various benign and malignant upper gastrointestinal diseases.METHODS:...Full Text Available
AIM: To investigate the effects of gallbladder stones on motor functions of the gallbladder and the dynamics of bile flow in asymptomatic gallstone disease.METHODS: Quantitative hepatobiliary...Full Text Available
In contrast to the increasing availability of information pertaining to the care of children with chronic kidney disease (CKD) from large-scale observational and interventional studies, epidemiological...Full Text Available
BackgroundMultiple myeloma is a hematologic malignancy associated with the development of a destructive osteolytic bone disease.ResultsMathematical...Full Text Available
ObjectiveTo develop a simple summary risk score for the prediction of Alzheimer disease in elderly persons based on their vascular risk profiles.DesignFull Text Available
We report Sr, Pd and Ag abundances for a sample of metal-poor field giants and analyze a larger sample of Y, Zr, and Ba abundances. The [Y/Zr] and [Pd/Ag] abundance ratios are similar to those measured for the r-process-rich stars CS 22892-052 and CS 31082-001. The [Pd/Ag] ratio is larger than predicted from the solar-system r-process abundances. The constant[Y/Zr] and [Sr/Y] values in the field stars places strong limits on the contributions of the weak s-process and the main s-process to the light neutron-capture elements. Stars in the globular cluster M 15 possess lower [Y/Zr] values than the field stars. There is a large dispersion in [Y/Ba]. Because the r-process is responsible for the production of the heavy elements in the early Galaxy, these dispersions require varying light-to-heavy ratios in r-process yields.
Reactively sputtered tantalum nitride (Ta_2N) has been investigated as a diffusion barrier between Pd_2Si and aluminum and CoSi_2 and Al. Ta_2N is found to be an excellent matallurgical diffusion barrier for the two systems up to 555 "0C, with no intermixing observed in Rutherford backscattering and Auger electron spectroscopic studies. Schottky barrier devices n-Si/Pd_2Si/Ta_2N/Al were excellent and showed no deterioration after annealing at 500 "0C. However, similar devices with CoSi_2 contacts and Ta_2N barrier showed a creation of high contact resistance between the silicide and the as-deposited nitride.
Reactively sputtered tantalum nitride (Ta/sub 2/N) has been investigated as a diffusion barrier between Pd/sub 2/Si and aluminum and CoSi/sub 2/ and Al. Ta/sub 2/N is found to be an excellent matallurgical diffusion barrier for the two systems up to 555 /sup 0/C, with no intermixing observed in Rutherford backscattering and Auger electron spectroscopic studies. Schottky barrier devices n-Si/Pd/sub 2/Si/Ta/sub 2/N/Al were excellent and showed no deterioration after annealing at 500 /sup 0/C. However, similar devices with CoSi/sub 2/ contacts and Ta/sub 2/N barrier showed a creation of high contact resistance between the silicide and the as-deposited nitride.
Bilayers of pure palladium and gold films were evaporated alternatively on (100) and (111) monocrystalline silicon substrates. After annealing, in a vacuum furnace from 100 to 650degreeC during 30min, the growth sequence of the Pd2Si and PdSi phases that evolved as the result of the diffusion reaction was examined by means of Rutherford backscattering spectrometry (RBS), X-ray diffraction (XRD), whereas the surface morphology was investigated by scanning electron microscopy (SEM) technique. The effect of the intermediate gold layer is investigated in order to test its effectiveness as barrier for Cu and Si atoms interdiffusion and its influence on the morphology of the formed palladium silicides. The effect of substrate orientation on the palladium silicides growth and formation was also e...
The redistribution of implanted As and Sb following metal-silicide formation of Pt, Pd, and Ni has been studied. The phases of the silicides used were PtSi, Pd/sub 2/Si, and NiSi. Investigations with Rutherford backscattering analysis showed that after the formation of the silicides, the Sb was always found in the silicide layer near the surface of the samples, whereas PtSi and Pd/sub 2/Si caused a partial rejection of As for implanted doses of 2 x 10/sup 15/ cm/sup -2/ and higher. No rejection of As was found after the formation of NiSi. The results are discussed in terms of solid solubilities and impurity-metal compound formation. The data presented has implications in the fabrication of Ohmic contacts and the adjustments of the heights of Schottky barriers on silicon.
The redistribution of implanted As and Sb following metal-silicide formation of Pt, Pd, and Ni has been studied. The phases of the silicides used were PtSi, Pd_2Si, and NiSi. Investigations with Rutherford backscattering analysis showed that after the formation of the silicides, the Sb was always found in the silicide layer near the surface of the samples, whereas PtSi and Pd_2Si caused a partial rejection of As for implanted doses of 2 x 10"1"5 cm"-"2 and higher. No rejection of As was found after the formation of NiSi. The results are discussed in terms of solid solubilities and impurity-metal compound formation. The data presented has implications in the fabrication of Ohmic contacts and the adjustments of the heights of Schottky barriers on silicon.
A dense Pd-Ag membrane reactor (MR) with 100% hydrogen selectivity packed with either Rh/La2O3 or Rh/La2O3-SiO2 as catalysts was used to carry out the dry reforming of methane. The membrane reactor simulation was performed using a well-known reactor model. For this purpose, we employed the equations derived from complete kinetic studies of the dry reforming of methane reaction in connection with both catalysts. In addition, we developed the kinetic equation for the reverse water gas shift reaction (RWGS). The combination of detailed kinetic studies with the measured permeation flux for the Pd-Ag membrane allowed a complete comparison between experimental and simulated operation variables. The variables studied for both catalysts were methane conversion and hydrogen permeation as a function...
Magnetization, neutron diffraction and "1"6"6Er Moessbauer measurements on ErPd_2Si_2 are reported. Below 4.8 K ErPd_2Si_2 orders AF with complex modulated magnetic structures, where the Er moments are aligned along the c-axis. At 1.5 K a squared structure with #mu#_E_r #approx# 7.8(1)#mu#_B is found while a saturation Er moment of 8.2(2)#mu#_B is inferred from the hyperfine field data. The temperature dependence of the Moessbauer spectra in the paramagnetic region is explained in the framework of a relaxation model implying excited crystal field levels. Its analysis is used to estimate the B"m_n CEF parameters. (orig.).
Single-crystalline CeRh{sub 2}Si{sub 2} and CePd{sub 2}Si{sub 2} were grown by the Czochralsky pulling method and the temperature dependence of magnetic susceptibility was investigated. The crystalline electric field (CEF) states in each compound were determined by considering the tetragonal CEF Hamiltonian with mean-field approximation. Interactions between Ce{sup 3+} ion and the surrounding ligands in CeRh{sub 2}Si{sub 2} turned out to be strong and highly anisotropic in comparison to CePd{sub 2}Si{sub 2}. (orig.) 10 refs.
In the present study, element interdiffusions at the cofired interface of 9/1 Ag/Pd electrode and lead magnesium niobate (PMN)-based ferroelectrics were investigated using Auger Electron Spectroscopy (AES). Intense interdiffusions at the interface were observed while Ag and Pd could penetrate into the ceramics for about 1 {mu}m. Ag-doping experiments were carried out to further study the effects of Ag diffusion on electrical properties of the ceramics. The results showed that Ag could be incorporated into solid solution of the ceramics as Ag{sup +}. As a whole, the Curie temperature (Tc) and dielectric constant of the ceramics decreased with Ag addition. However, Ag addition had no obvious effect on the insulation resistivity. The results inferred that Ag{sup +} could substitute for Pb{sup 2+} at A site of ABO{sub 3} lattice, thereby oxygen vacancies were generated.
The phase stability of silicides of Ni, Pt and Pd in contact with single crystal or amorphous silicon is examined. The presence of a particular silicide phase is identified by X-ray diffraction, and Rutherford backscattering is used to study composition. It is concluded that Pt or Pd silicides are suitable for Schottky barriers. Layers of silicon can be grown quickly by solid phase epitaxy at temperatures of 300-500C and using an intermediate metal film. Experimental results are reported. Doped layers have been obtained which have electrical characteristics suitable for the junctions in solar cells. The effects of impurities and orientation of the substrate on the growth kinetics are discussed.
Palladium deposition on Pt(110) electrodes was studied. Differently from Pt(111) and Pt(100), first and further layers cannot be distinguished in this case only through the voltammetric behavior of hydrogen and anion adsorption. The potential of zero total charge (pztc) was determined as a function of the amount of deposited Pd using CO charge displacement experiments and voltammetric curves. The variation of the voltammetric charge due to hydrogen and anion adsorption has been followed during Pd deposition. The voltammetric charge between 0.06 and 0.4V first decreases to a minimum, then increases and finally becomes stable, suggesting that the surface is finally covered with a Pd multilayer. The pztc and CO oxidation charge show similar behavior. CO oxidation, NO reduction and Cu UPD were...
Catalyst deactivation during steam reforming of transportation fuels, primarily due to sulfur poisoning and carbon deposition, is a major hurdle in the commercialization of fuel cell technologies. In an attempt to better understand the phenomena, a previously formulated multi-component (Ni, Pd, Rh) catalyst supported on g-Al2O3 was studied under steam reforming of Jet A spiked with thiophene to achieve a total sulfur content of 1000ppm by weight. Analysis of fresh catalysts showed the presence of two groups of active metal particles, primarily distinguished by their size and composition; small particles (1-5nm) largely comprised of Rh and large particles (10-20nm) that were predominantly Ni, with or without the presence of Pd. Analysis of used catalysts showed sintering of crystallites con...
The growth of the Pd{sub 2}Si thin fllms on Si(111) substrates has been monitored by an {ital in} {ital situ} x-ray diffraction technique in vacuum and in helium atmosphere from 160 to 250 {degree}C. A familiar parabolic growth rate was found, confirming the diffusion-controlled film growth process. The activation energies were found to be 1.34 and 1.37 eV for the measurements performed in vacuum and helium environment, respectively. Stress relaxation in the growing Pd{sub 2}Si fllm was observed when the reaction temperature exceeds 200 {degree}C. The relaxed films showed a higher degree of texture as evidenced by the rocking curve measurements.
The growth of the Pd{sub 2}Si thin fllms on Si(111) substrates has been monitored by an {ital in} {ital situ} x-ray diffraction technique in vacuum and in helium atmosphere from 160 to 250 {degree}C. A familiar parabolic growth rate was found, confirming the diffusion-controlled film growth process. The activation energies were found to be 1.34 and 1.37 eV for the measurements performed in vacuum and helium environment, respectively. Stress relaxation in the growing Pd{sub 2}Si fllm was observed when the reaction temperature exceeds 200 {degree}C. The relaxed films showed a higher degree of texture as evidenced by the rocking curve measurements.
Phase relations in the ternary system Ce-Pd-Si have been established for the isothermal section at 800 deg. C based on X-ray powder diffraction and EMPA techniques on about 130 alloys, which were prepared by arc-melting under argon or powder reaction sintering. Eighteen ternary compounds have been observed to participate in the phase equilibria at 800 deg. C. Atom order was determined by direct methods from X-ray single-crystal counter data for the crystal structures of tau{sub 8}-Ce{sub 3}Pd{sub 4}Si{sub 4} (U{sub 3}Ni{sub 4}Si{sub 4}-type, Immm; a=0.41618(1), b=0.42640(1), c=2.45744(7) nm), tau{sub 16}-Ce{sub 2}Pd{sub 14}Si (own structure type, P4/nmm; a=0.88832(2), c=0.69600(2) nm) and also for tau{sub 18}-CePd{sub 1-x}Si{sub x} (x=0.07; FeB-type, Pnma; a=0.74422(5), b=0.45548(3), c=0.58569(4) nm). Rietveld refinements established the atom arrangement in the structures of tau{sub 5}-Ce{sub ...
Silicon carbide (SiC) based electronic devices are of great importance for applications under the condition of high temperature, high power and high radiation. Schottky diodes of Palladium/SiC are good candidates for hydrogen and hydrocarbon gas sensors at elevated temperature. The detection sensibility of the diodes has been found heavily temperature dependent. In this work, the electrical and chemical properties of Pd/SiC Schottky contacts were studied by XPS and AES at different annealing temperatures. Schottky diodes were made by depositing ultra-thin palladium films onto a silicon carbide substrate. No significant change in the Schottky barrier height of the Pd/SiC contact was found in the temperature range of 300-673K. Palladium diffusion into SiC and the formation of palladium silicides were observed at room temperature and became significant at 300^oC and higher temperature. The mechanism of diffusion and reaction at the ...
New palladium(II) complexes (2), bearing NHC/TPPTS ligands, (NHC=benzimidazol-2-ylidene; TPPTS=triphenylphosphine-3,3',3''-trisulfonic acid trisodium salt) have been prepared and characterized by elemental analyses and spectroscopic methods. Their ability to catalyze the Suzuki-Miyaura reaction in neat water has been studied at 100^oC. Very high activities have been observed in the coupling of phenylboronic acid with aryl chlorides in the presence of 1% of the catalyst. We have compared the electronic properties of cis-[PdBr2(NHC)(TPPTS)] with the related complexes, [PdX2(NHC)]2 and [trans-PdBr2(NHC)(pdca)] (pdca=pyridine-2,6-dicarboxyic acid) (3) via three different techniques: cyclic voltammetry, thermogravimetric analysis and ^1^3C NMR spectroscopy.
Phase relations in the ternary system Ce-Pd-Si have been established for the isothermal section at 800degreeC based on X-ray powder diffraction and EMPA techniques on about 130 alloys, which were prepared by arc-melting under argon or powder reaction sintering. Eighteen ternary compounds have been observed to participate in the phase equilibria at 800degreeC. Atom order was determined by direct methods from X-ray single-crystal counter data for the crystal structures of t8-Ce3Pd4Si4 (U3Ni4Si4-type, Immm; a=0.41618(1), b=0.42640(1), c=2.45744(7)nm), t16-Ce2Pd14Si (own structure type, P4/nmm; a=0.88832(2), c=0.69600(2)nm) and also for t18-CePd1-xSix (x=0.07; FeB-type, Pnma; a=0.74422(5), b=0.45548(3), c=0.58569(4)nm). Rietveld refinements established the atom arrangement in the structures of...
The crystal structure of the compound Sm_4Pd_4Si_3 was determined by the single-crystal method (KM-4 automatic diffractometer, Mo K#alpha# radiation). Sm_4Pd_4Si_3 has the monoclinic Nd_4Rh_4Ge_3 type structure: space group C2/c, mC44 (No. 15), a=20.693(6), b=5.584(1), c=7.699(2) A, #beta#=109.48(3) , V=838 A"3, Z=4, #mu#=36.23 mm"-"1, R_F=0.0537, R_W=0.0435 for 1652 unique reflections. The coordination numbers of samarium atoms are 17 and 18. For palladium and silicon atoms icosahedra and trigonal prisms with additional atoms are typical as coordination polyhedra. The structure of Sm_4Pd_4Si_3 is composed of fragments of the YPd_2Si and Y_3Rh_2Si_2 structure in a ratio 1:1. (orig.).
The present work is to study effects of neutron irradiation on the structure of amorphous Pb_8_0 Si_2_0 and Pd_7_7_._5 Cu_6 Si_1_6_._5 alloys by using X-ray diffraction techniques. differential scanning calorimertry (DSC) and internal friction measurements. The irradiation will produce obvious changes in the pair correlation function g(r) and radial distribution function RDF (r). The increase of crystallization temperature (Tx) and enthalpy of two specimens were found by DSC measurements after irradiation. The results of internal friction measurement show that the internal friction of the irradiated Pd_8_0Si_2_0 alloy is higher than that of the unirradiated in the temperature range of T
Marker experiments for studying the mass transport through a palladium silicide layer on a crystalline substrate during thermal oxidation at 700 to 850 deg C have been reported recently. In this work argon gas embedded in amorphous silicon during sputtering was implemented as the inert marker and the oxidation of PdSi was processed above 900 deg C. At this high-temperature oxidation silicon-rich silicide PdSisub(y), with y exceeding 5, may be obtained. This can be anticipated by considering the Pd-Si phase diagram which shows the liquid phase may appear at an annealing temperature above 892 deg C. As a result, a non-stoichiometric and non-uniform silicide layer may develop at the sample surface. Marker analysis showed that both palladium and silicon dissociated at the Pdsub(x)Si/ SiO_2 interface and moved to the substrate with the silicon being the dominant diffuser. The Rutherford backscattering spectra (RBS) showing the ...
A Pd(0)-catalyzed intramolecular Heck-type reaction of oxime ether has been developed, providing convenient access to heterocyclic oximes. PMID:21964259
Available data are presented which support the supposition that metals and alloys with a negative low-temperature Hall coefficient are apparently not superconducting. (author).
Neutron powder diffraction and magnetometric studies of the HoRh_2_-_xPd_xSi_2 series of solid solutions (x=0, 0.5, 0.75, 1.0, 1.5, 1.8) are reported. The intermetallics investigated crystallize in the body-centred-tetragonal ThCr_2Si_2-type structure (space group I4/mmm). All the samples order antiferromagnetically at low temperatures. For low values of the dilution parameter x a simple collinear antiferromagnetic structure of the AFI type is stable. Below T_N the magnetic moments are parallel to the c-axis and then, below T_t, deflect forming an angle #psi# with the c-axis. Further replacement of Rh by Pd results in the development of a sine-wave-modulated magnetic structure with one two-component propagation vector and magnetic moments in the basal plane. For x=1.8 a sine-wave-modulated structure similar to that reported for HoPd_2Si_2 (i.e. with a two-component propagation vector and magnetic moments parallel to the ...
Pd/sub 2/Si layers produced by evaporation or sputtering onto silicon substrates were examined by high resolution electron microscopy, microdiffraction, X-ray, energy loss and Auger spectroscopy. The Si-Pd/sub 2/Si interfaces produced by evaporation were in all cases rougher and more polycrystalline than those produced by sputtering. X-ray microanalysis showed the predictable variation in palladium distribution across the interface but quantification did not produce the expected palladium-to-silicon ratios, primarily because of probe broadening and X-ray-induced fluorescence. Energy loss spectra showed plasmon energy shifts and changes in Si L edge shape due to bond formation with palladium. Auger data provided evidence for a small amount of oxygen at the Si-Pd/sub 2/Si interface. Electrical measurements of the ideality factor for Schottky barriers made from the materials produced higher values for the rougher ...
The PERMCAT process chosen for the final clean-up stage of the Tokamak Exhaust Processing system of the ITER tritium plant combines in a single component a catalytic reactor and a permeator using Pd/Ag membranes. This study covers the mechanical behaviour of a Pd/Ag membrane under different operating conditions. The consequences of hydrogen uptake by the membrane during nominal operation but also during off-normal events are presented. Depending on the operating conditions, expansions around 2% and significant deformations are observed. Different mechanical designs of PERMCAT reactors are then discussed. The first generation comprises finger-type membranes and two new mechanical designs use either additional edge welded bellows or a special corrugated Pd/Ag membrane. These upgraded designs improve the robustness and simplify the geometry of the component. The experimental validation of these new units has been carried out ...
The PERMCAT process chosen for the final clean-up stage of the Tokamak Exhaust Processing system of the ITER tritium plant combines in a single component a catalytic reactor and a permeator using Pd/Ag membranes. This study covers the mechanical behaviour of a Pd/Ag membrane under different operating conditions. The consequences of hydrogen uptake by the membrane during nominal operation but also during off-normal events are presented. Depending on the operating conditions, expansions around 2% and significant deformations are observed. Different mechanical designs of PERMCAT reactors are then discussed. The first generation comprises finger-type membranes and two new mechanical designs use either additional edge welded bellows or a special corrugated Pd/Ag membrane. These upgraded designs improve the robustness and simplify the geometry of the component. The experimental validation of these new units has been carried out ...
Colistin is increasingly used as last-line therapy against Gram-negative pathogens. The pharmacokinetic (PK)/pharmacodynamic (PD) index that best correlates with the efficacy of colistin remains undefined....Full Text Available
We present first-time measurements of the Fermi surface and low-energy electronic structure of intermetallic compounds Gd_2PdSi_3 and Tb_2PdSi_3 by means of angle-resolved photoelectron spectroscopy (ARPES). We show that the Fermi surface in both compounds consists of an electron barrel at the #GAMMA# point surrounded by spindle-shaped electron pockets originating from the same band, with the band bottom of both features lying at 0.5 eV below the Fermi level. From the experimentally measured band structure, we estimate the momentum-dependent RKKY coupling strength and demonstrate that it is peaked at the 1/2#GAMMA# K wave vector. Comparison with neutron diffraction data from the same crystals shows perfect agreement of this vector with the propagation vector of the low-temperature in-plane magnetic order, thereby demonstrating the decisive role of the Fermi surface geometry in explaining the complex magnetically ordered ground state of ternary ...
AimsTo describe the pharmacokinetic–pharmacodynamic (PK–PD) characteristics of the direct thrombin inhibitor dabigatran in hip replacement patients by assessing coagulation...Full Text Available
Two major modes of CO adsorption on SiO{sub 2}-supported Pd reflect different extents of back-donation, which is, at least in part, controlled by the local electron density at the adsorption site. The fraction of CO in the bridging mode (B) increases and that of the linear mode (L) decreases, with increasing size of the Pd particles, indicating high electron density at Pd atoms in terraces of close-packed crystal faces, in agreement with Smoluchowski's classical model. For samples reduced at 300{degree}C our data points and those of other authors are located on a common curve of B/L vs metal dispersion. Extensive reduction at 600{degree}C results in significantly lower B/L values, attributed to the incipient formation of a palladium silicide. Oxidation followed by reduction at 300{degree}C destroys the silicide, and the B/L value returns to the original curve.
Two major modes of CO adsorption on SiO{sub 2}-supported Pd reflect different extents of back-donation, which is, at least in part, controlled by the local electron density at the adsorption site. The fraction of CO in the bridging mode (B) increases and that of the linear mode (L) decreases, with increasing size of the Pd particles, indicating high electron density at Pd atoms in terraces of close-packed crystal faces, in agreement with Smoluchowski's classical model. For samples reduced at 300{degree}C our data points and those of other authors are located on a common curve of B/L vs metal dispersion. Extensive reduction at 600{degree}C results in significantly lower B/L values, attributed to the incipient formation of a palladium silicide. Oxidation followed by reduction at 300{degree}C destroys the silicide, and the B/L value returns to the original curve.
To attain reproducible and stable contacts to compound semiconductor devices, it is necessary to achieve thermodynamically stable phases after the reaction of metals with the compound semiconductor. In this study, the final phases produced by the reactions between GaAs and thin metal films of Co, Rh, Ir, Ni, Pd, and Pt have been investigated. They are identified as MGa for M = Co, Rh, Ni, Pd, and Pt, monoarsenides of Co and Ni, diarsenides of Rh, Ir, Pd, and Pt, and Ir/sub 3/Ga/sub 5/. These phases, if deposited directly onto GaAs, will produce thermally stable contacts. In addition to the identification of these stable phases, analyses of the products of thin-film M/GaAs reactions by transmission electron microscopy, x-ray diffraction, and Rutherford backscattering spectrometry reveal the distribution, grain size, and crystallographic texture of these end phases. Trends in these observations across the six metal/GaAs ...
The compounds CePdSi{sub 2}, CeIrSi{sub 2} and CeRhSn{sub 2} have been synthesized and studied by X-ray diffraction, electrical resistivity and magnetic susceptibility. The magnetic susceptibility of CePdSi{sub 2} exhibits two peaks at 6.8 K and 2.5 K, respectively, indicating two antiferromagnetic phase transitions, while that of CeIrSi{sub 2} shows a broad maximum at 150 K, characteristic of valence fluctuating Ce-compounds. CeRhSn{sub 2} remains paramagnetic down to 5 K. The resistivity of CeIrSi{sub 2} exhibits a T{sup 2} dependence at low temperatures, indicating a Fermi-liquid ground state, while those of CePdSi{sub 2} and CeRhSn{sub 2} shows the presence of Kondo and crystal field effects. (orig.). 5 refs.
The annealing behavior of the radiation damage in epitaxial Pd_2Si and NiSi_2 films on Si, due to the implantation of 100 keV Ar ions, is investigated by using the channeling technique with "4He ions. (U.K.).
The sharp, temperature induced, continuous valence transition in EuPd/sub 2/Si/sub 2/ is drastically changed by doping with Sn at the Si site up to 5 at.%. Only a first order valence transition occurs for a 3% Sn doped sample and the 2/sup +/ component which survives the valence transition orders magnetically at 4.2 K. No valence transition at all occurs for a 5% Sn doped sample right up to 1.9 K and magnetic ordering sets in around 30 K.
Depth resolved positron annihilation studies on Pd/Si thin film system have been carried out to investigate silicide phase formation and vacancy defect production induced by thermal annealing. The evolution of defect sensitive S-parameter clearly indicates the presence of divacancy defects across the interface, due to enhanced Si diffusion beyond 870 K consequent to silicide formation. Corroborative glancing incidence X-ray diffraction (GIXRD), Auger electron spectroscopy (AES) and Rutherford backscattering spectrometry (RBS) have elucidated the aspects related to silicide phase formation and Si surface segregation.
We report a study of the nonmetal-metal transition of free-standing Pd{sub N} clusters (2{<=}N{<=}21) carried out through two different theoretical approaches that are extensively employed in electronic structure calculations: a semi-empirical tight-binding (TB) model and an ab initio DFT pseudopotential model. The calculated critical size for the metallic transition decreases rapidly with the temperature and an oscillatory dependence with the cluster size is obtained, particularly in the DFT approach. The TB model describes the metallic behavior for cluster sizes beyond N{approx}12 well. Our obtained critical size at room temperature is of the order of the experimental estimation.
The magnetic structure of a tetragonal Ce(Ru_0_._9_6Pd_0_._0_4)_2Si_2 single crystal, determined by neutron diffraction measurements, is similar to that observed in Rh doped alloys. The magnetic moments are oriented and modulated along the c-axis. Here the wave vector is incommensurate: k=(0,0,0.38). At 1.5 K, the moment is estimated to about 0.3 #mu#_B. Magnetization, magnetoresistance and Hall effect measurements performed on this alloy are also reported. (orig.).
The magnetic susceptibility of the ternary compounds, RPd_2Si_2 (where R=Gd, Tb, Dy, Ho and Er) has been measured. GdPd_2Si_2 and TbPd_2Si_2 order antiferromagnetically at 13 and 20 K respectively; the rest of the compounds do not show clear ordering down to 4.2 K. Palladium carries no moment in these compounds. The De Gennes formula is not obeyed indicating that the exchange interaction between the 4f moments via conduction electrons is not isotropic. (orig.).
The magnetic excitations of the Kondo compound CePd{sub 2}Si{sub 2} below its Neel temperature (T{sub N} = 10 K) have been studied by inelastic neutron scattering. At T = 1.6 K the data are best represented by two dispersive inelastic modes. Their linewidth ({proportional to} 0.5 meV) indicates substantial broadening, which is ascribed to Kondo-type local fluctuations. (orig.).
The results obtained from the magnetization, specific heat and electrical resistivity measurements on a polycrystalline sample of Pr_2Pd_3Si_5 are reported. The temperature dependence of magnetic susceptibility at low field (0.01 T) exhibits pronounced anomaly below 7 K due to antiferromagnetic ordering. The electrical resistivity and specific heat data also exhibit sharp transition at 6.6 K evidencing the onset of antiferromagnetic order. A fit to the electrical resistivity data below 6 K suggests the presence of an energy gap in magnon spectrum in the ordered state. (author)
The application of medium energy ion scattering in combination with channelling and blocking to the study of the initial stages of palladium silicide formation is discussed. After a brief description of the experimental arrangement and method, the effects on the Rutherford backscattering spectra of depositing small quantities of palladium on clean Si(111) are reported. The uniformity and thermal stability of thin palladium silicide films grown at room temperature were measured. Finally, channelling and blocking results were used to carry out a structural analysis of thin epitaxial Pd/sub 2/Si layers.
The application of medium energy ion scattering in combination with channelling and blocking to the study of the initial stages of palladium silicide formation is discussed. After a brief description of the experimental arrangement and method, the effects on the Rutherford backscattering spectra of depositing small quantities of palladium on clean Si(111) are reported. The uniformity and thermal stability of thin palladium silicide films grown at room temperature were measured. Finally, channelling and blocking results were used to carry out a structural analysis of thin epitaxial Pd_2Si layers. (Auth.).
Experimental data in the hybridised compound YbPd{sub 2}Si{sub 2} is compared with the results obtained with a recently proposed hybridisation model, based on the ''large-degeneracy expansion'' approximation, which takes into account the crystal field splittings of the rare earth ion energy levels. With a unique set of parameters, satisfactory agreement is simultaneously obtained for the thermal variation of the electronic specific heat, of the magnetic susceptibility and of the electric field gradient at the Yb site, as well as for the field variation of the low temperature magnetisation. (orig.).
Measurements of the magnetic susceptibility #chi#, specific heat C, and thermoelectric power S were carried out for the solid solution Ce(Ni_xPd_1_-_x)_2Si_2 (0#<=#x#<=#1). With increasing x, the ground state changes from an antiferromagnetic Kondo state (x<0.2) to an intermediate valence state (x>0.3). The heavy fermion state was found to evolve at the crossover concentration at x=0.2, where the long-range magnetic order seems to disappear. [copyright] 2001 American Institute of Physics.
In this study, different proportions of silver-palladium alloy used as an inner electrode are adopted to fabricate (Zn,Mg)TiO3-based multilayer ceramic capacitors. Effects of sintering temperature, and measuring frequency on the dielectric properties of the samples with different proportions of the Pd-Ag inner electrode are investigated. The continuity of the inner electrode and the proportion of Pd-Ag of the inner electrode of samples sintered at different temperatures play important roles in determining the dielectric properties.
The total and differential atomic pair-correlation functions of an icosahedral (quasicrystalline) solid were determined for the first time, directly by the differential anomalous-x-ray-scattering technique using synchrotron radiation. The observed atomic distances involving uranium atoms in icosahedral Pd/sub 58.8/U/sub 20.6/Si/sub 20.6/ suggest the presence of a quasicrystalline sublattice with vertex decoration. The pair distribution functions in the icosahedral and amorphous phases are similar up to the second-nearest neighbors, or up to 6 A-circle.
The total and differential atomic pair-correlation functions of an icosahedral (quasicrystalline) solid were determined for the first time, directly by the differential anomalous-x-ray-scattering technique using synchrotron radiation. The observed atomic distances involving uranium atoms in icosahedral Pd/sub 58.8/U/sub 20.6/Si/sub 20.6/ suggest the presence of a quasicrystalline sublattice with vertex decoration. The pair distribution functions in the icosahedral and amorphous phases are similar up to the second-nearest neighbors, or up to 6 A-circle.
Changes in transverse phonon sound velocity were measured during low temperature irradiation of amorphous Pd{sub 80}Si{sub 20} with 3.5 MeV krypton ions. The sound velocity decreases as a function of the ion fluence and shows a tendency to saturate at large fluences at a relative change of {minus}4.7%. The changes in sound velocity were used to determine the changes in shear elastic constant and in Debye temperature both of which were in reasonable agreement with the value reported in the literature.
We used epidemiologic data for human West Nile virus (WNV) disease in Colorado from 2003 and 2007 to determine 1) the degree to which estimates of vector-borne disease occurrence is influenced by spatial...Full Text Available
Laboratory-based surveillance of Lyme disease in Connecticut during 1984 and 1985 identified 3,098 persons with suspected Lyme disease; 1,149 were defined as cases. Lyme disease incidence in Connecticut...Full Text Available
Crystalline Pd_9Si_2 possesses an orthorhombic structure (Pnma) that is characterized by augmented triangular prismatic coordination of the silicon atoms such as that which occurs in several metal-rich transition-metal silicides. Recent neutron diffraction results for deuterium solution in this crystalline phase have indicated that deuterium occupies only one type of interstice, i.e., a Pd-defined pyramidal site in a four-fold position situated on a quadrilateral face of an empty triangular prism. The vibrational dynamics of both H and D located at this site were investigated by neutron vibrational spectroscopy. The low-temperature density of states (DOS) of H in Pd_9Si_2H_0_._2_5 indicates three well-defined optic vibrations located at 49.4, 67.2 and 75.5 meV. The lowest-energy feature is assigned to the normal-mode vibration perpendicular to the pyramidal base and the two higher-energy features are assigned to the two ...
Abstract A series of small phosphazene ligands with pendant 6-phenyl-2,2--bipyridyl moieties, namely L1 [N3P3(OPh)5(OPhbpyPh)], L2 [N3P3(biph)2(OPhbpyPh)2], L3 [N3P3(tBubiph)2(OPhbpyPh)2], L4 [N3P3(biph)2(OPhbpyPh)Cl] and L5 [N3P3(biph)2(OPhbpyPh)(OPh)] [OPhbpyPh = 4-(4-phenoxy)-6-phenyl-2,2--bipyridine, OPh = phenoxy, biph = 2,2--oxybiphenyl and tBubiph = 4,4--di-tert-butyl-2,2--oxybiphenyl], have been used to synthesise the new cyclometallated palladium(II) and platinum(II) complexes [(L1-H)PdCl], [(L1-H)PtCl], [(L1-H)(PdCl)2], [(L3-H)(PdCl)2], [(L4-H)PtCl], [(L5-H)PtCl] and the rhenium(I) complex [L5Re(CO)3Cl]. Single-crystal X-ray diffraction analysis was performed on the free ligand L2 and the palladium complexes [(L1-H)PdCl] and [(L3-H)(PdCl)2]. In both PdII complexes, the metal cent...
An x-ray diffraction approach has been developed for determination of the kinetics of growth of Pd/sub 2/Si layers. Epitaxial Pd/sub 2/Si films were grown on Si(111) substrates over a temperature range of 160-222/sup 0/C by a solid-state reaction between the substrates and the Pd overlayers. The parabolic rate equation was verified and rate constants showed Arrhenius behavior with an activation energy E/sub a/ = 1.06 eV and prefactor k/sub 0/ = 7 x 10/sup -4/ cm/sup 2//s. The low value of E/sub a/ suggests a short-circuit diffusion mechanism. It is reasonable to expect that impurities and microstructure may play important roles in the growth process. Impurity levels in the specimens were evaluated by analytic techniques suited to thin-film study: Rutherford backscattering spectrometry, secondary ion mass spectrometry, and Auger electron spectrometry. No impurities were present at concentrations approaching 1 at. %. Some O, ...
Formaldehyde oxidation was examined in a laboratory reactor over alumina-supported Pt, Pd, Rh, Ag, Cu-Cr, and Pd-Ag catalysts as part of a program to develop catalysts for lean-exhaust methanol-fueled vehicles. In general, the H/sub 2/CO oxidation behavior of the catalysts paralleled the CH/sub 3/OH oxidation behavior reported in Parts 1 and 2 of this series (Appl. Catal. 27(1986) 83; J. Catal. 103(1987) 419). Principal similarities were: high activity of Pt when there was no carbon monoxide (CO) in the feed, but strong inhibition by added CO; lower activity of Ag and Cu-Cr catalysts, but only weak inhibition due to added CO; enhanced activity of the Pd-Ag catalyst compared to Pd and Ag alone for feeds containing CO in addition to H/sub 2/CO; and, relatively poor activity of the Rh catalyst. The most unusual behavior was observed with the Pd catalyst, which showed local minima in ...
Ab initio calculations of the electronic structure were performed for the silver palladium oxide, Ag_2PdO_2, by the full potential mixed linearized augmented plane wave and augmented plane wave plus local orbitals method (mixed LAPW/APW+lo) within the density functional theory and using the generalized gradient approximation (GGA96, Phys. Rev. Lett. 77 (1996) 3865) for the exchange-correlation potential. The lattice parameters were calculated from the ground-state total energy versus volume curve, and are in good agreement with the available experimental results. Our calculations of band structure predicted that the compound Ag_2PdO_2 has indirect band gap, and the Pd 4d states strongly hybridize with the O 2p states all over the valence bands and conduction bands. The valence bands are composed mainly of Ag, Pd 4d states and O 2p states, while the conduction bands consist mainly of the ...
The aims of this study were to quantify the severity and extent of subclinical interstitial lung disease as depicted on HRCT and to study the relationship between the patterns of lung disease quantified by HRCT and the functional parameters and bronchoalveolar lavage findings in patients with rheumatic diseases. The results confirm that HRCT is a sensitive tool in detecting interstitial lung disease in patients with rheumatic diseases with no signs and symptoms of pulmonary involvement. The relationship between the different HRCT patterns and bronchoalveolar lavage cell profiles can identify patients at higher risk of developing irreversible lung fibrosis. A long-term, prospective follow-up study is needed to determine whether these patients will develop over pulmonary disease.
The case is presented of a 64-year-old man who complained on admission of discomfort in the right shoulder at the time of excision of a large section of the axillary skin which contained extra-mammary Paget disease. Shortly thereafter, radiological studies of the humerus and scapula showed obvious malignant disease which proved to be metastatic upon biopsy of the humerus and pathological studies of the excised area of extra-mammary Paget disease in the axillary skin. The patient died twelve months after the diagnosis was established with widespread metastatic disease. The literature on the subject was reviewed and it was demonstrated that metastases to the skeleton from lesions of the skin are relatively rare. This case is exceptional because of the rapid fatal course and the extent of metastatic disease originating in extra-mammary Paget disease of the axillary ...
Effects of soil pH on damping-off of sugar beet by R. solani (AG2-2) and soil suppressiveness against the disease were studied by comparing disease incidences in pasteurized versus non-pasteurized, infested soils. Soil pH was correlated neither to disease incidence in five soils ranging from pH?4.5 to 7.2 nor to indigenous disease suppressiveness, the difference in disease incidences between non-treated soil and its pasteurized counterpart. When an alkaline soil was acidified with H2SO4, disease suppression markedly declined, increasing disease incidence in the non-pasteurized soil. Inversely, disease suppression was enhanced when an acidic soil was neutralized by adding Ca(OH)2. Soil amendment with dried peanut plant residue suppressed the disease in two pasteurized, near-neutral soils, l...
Ascochyta blight causes significant yield loss in pulse crops worldwide. Integrated disease management is essential to take advantage of cultivars with partial resistance to this disease. The most effective practices, established by decades of research, use a combination of disease-free seed, destruction or avoidance of inoculum sources, manipulation of sowing dates, seed and foliar fungicides, and cultivars with improved resistance. An understanding of the pathosystems and the inter-relationship between host, pathogen and the environment is essential to be able to make correct decisions for disease control without compromising the agronomic or economic ideal. For individual pathosystems, some components of the integrated management principles may need to be given greater consideration tha...
BackgroundMetastases to the stomach from an extra-gastric neoplasm are an unusual event, identified in less than 2% of cancer patients at autopsy. The stomach may be involved by hematogenous spread from a distant primary (most commonly breast, melanoma or lung), or by contiguous spread from an adjacent malignancy, such as the pancreas, esophagus and gallbladder. These latter sites may also involve the stomach via lymphatic or haematogenous spread. We present three cases of secondary gastric malignancy.Methods/ResultsThe first is a 19-year-old male who received a diagnosis of testicular choriocarcinoma in September 2004. Metastatic malignancy was demonstrated in the stomach after partial gastrectomy was performed to control gastric hemorrhage.The second is a 75-year-old male, generally well, who was diagnosed with adenocarcinoma of the lung in September 2005. Poorly differentiated adenocarcinoma of the lung was demonstrated in a subsequent biopsy of "gastric ...
Nerve growth factor (NGF), a survival factor for neurons enforces pain by sensitizing nociceptors. Also in the pancreas, NGF was associated with pain and it can stimulate the proliferation of pancreatic cancer cells. Hepatic stellate cells (HSC) respond to NGF with apoptosis. Transforming growth factor (TGF)-b, one of the strongest pro-fibrogenic activators of pancreatic stellate cells (PSC) induced NGF and its two receptors in an immortalized human cell line (ihPSC) and primary rat PSC (prPSC) as determined by RT-PCR, western blot, and immunofluorescence. In contrast to HSC, PSC expressed both NGF receptors, although p75NTR expression was weak in prPSC. In contrast to ihPSC TGF-b activated both Smad signaling cascades in prPSC. NGF secretion was diminished by the activin-like kinase (ALK)...
Active oxygens produced by low-dose irradiation can induce the synthesis of proteins involved in the active oxygen reduction path and can activate the chemical self-defense mechanisms in vivo, which can alleviate the injuries caused by active oxygens themselves. The following findings suggests that it is not only by low-dose irradiation that can induce the responses described above but also by any physical and/or chemical stresses which can produce small amount of active oxygens in vivo. 1. X-irradiation with 0.5 Gy and/or water immersion and restraint induced heat shock protein (HSP)70 in rat stomach cells. HSP70 was also induced in adrenal cells by paraquat administration. 2. The SOD activity in pancreas of rat significantly increased by #gamma#-irradiation with 0.5 Gy. 0.5 Gy irradiation preceeding the alloxan administration significantly suppressed the increase in pancreatic lipid peroxides and in blood glucose levels, degranulation in #beta# cells, and ...
The Zollinger-Ellison syndrome (ZES) is taken as an example of the diagnostic and therapeutic strategy in gastro-entero-pancreatic endocrine tumours, given the standard characteristics of this procedure, whatever the nature of the primitive tumour. Management of ZES includes: anatomical localization of gastrinoma and of possible metastases, in 60 % of cases this step conditioning therapeutic indications and chances of cure; search of a type 1-multiple endocrine neoplasia (MEN A), in 25 % of cases; therapeutic indications: ablative surgery with curative intent in case of gastrinoma and of resectable liver metastases, palliative treatment otherwise: anti-secretory drugs, somatostatin analogues, chemotherapy and interferon {alpha}; long-term follow-up of patients with resected tumour. At each step, somatostatin receptor scintigraphy with indium 111-pentetreotide does play a pivotal role. (author). 110 refs.
Pancreatitis-associated protein (PAP) is a secretory pancreatic protein present in small amounts in normal pancreas and overexpressed during the acute phase of pancreatitis. In this paper, the authors describe the cloning, characterization, and chromosomal mapping of the human PAP gene. The gene spans 2748 bp and contains six exons interrupted by five introns. The gene has a typical promoter containing the sequences TATAAA and CCAAT 28 and 52 bp upstream of the cap site, respectively. They found striking similarities in genomic organization as well as in the promoter sequences between the human and rat PAP genes. The human PAP gene was mapped to chromosome 2p12 using rodent-human hybrid cells and in situ chromosomal hybridization. This localization coincides with that of the reg/lithostathine gene, which encodes a pancreatic secretory protein structurally related to PAP, suggesting that both genes derived from the same ancestral gene by duplication. 35 refs., 4 ...
This progress report covers period from Nov. 1, 1989 to Aug. 31, 1990. The long term objective was to develop receptor-binding radiotracers for SPECT or PET imaging of CNS or peripheral nervous system. The specific chemistry aims, as understood on the basis of past findings, were: to synthesize and develop a more polar analogs of 4IQNB, possessing similar binding characteristics but eliminated more rapidly from the surrounding tissues and the target organ, to design a method of introducing a technetium chelating group onto a molecule or cholinergic agent without drastic lowering of its apparent affinity, to synthesize and develop radiotracers based on m-AChR antagonists selective for one of the subtypes of the receptor. The chemistry service aims were to prepare and characterize (R,R)- and (R,S)-4IQNB and derivatives, to provide the triazene intermediate to other investigators, and to provide ({sup 123}I)4IQNB for in vivo imaging. The biochemistry aims were to characterize the vitro ...
Purified protein kinase C (C-kinase) from guinea pig pancreas and rat brain stimulated adenylate cyclase activity in purified rat adipocyte membranes. Cyclase stimulation occurred over 100 to 1000 mU/ml of C-kinase activity, required greater than 10 ..mu..M calcium, proceeded without a lag, was not readily reversible, and required no exogenous phospholipid. Moreover, C-kinase inhibitors, such as chlorpromazine and palmitoyl carnitine, inhibited selectively adenylate cyclase which was activated by C-kinase and calcium. Depending on assay conditions, 10 nM 12-0-tetradecanoylphorbol-13-acetate (TPA) either enhanced or was required for kinase action on cyclase. Also, TPA plus calcium promoted the quantitative association of C-kinase with membranes. Adenylate cyclase activation by C-kinase was seen both in the presence and absence of exogenous GTP, indicating that the kinase effect does not result from an action on the GTP-binding, inhibitory regulatory component (N/sub ...
Meningococcal disease is an infection caused by Neisseria meningitidis. Genetic factors contribute to host susceptibility and progression to disease, but the genes responsible for disease development are largely unknown. We report here a genome-wide association study for host susceptibility to meningococcal disease using 475 individuals with meningococcal disease (cases) and 4,703 population controls from the UK. We performed, in Western European and South European cohorts (consisting of 968 cases and 1,376 controls), two replication studies for the most significant SNPs. A cluster of complement factor SNPs replicated independently in both cohorts, including SNPs within complement factor H (CFH) (rs1065489 (p.936D
SummaryBackground Persistent Lyme Disease Symptoms (PLDS) have included fatigue, headaches, poor concentration and memory, lightheadedness, joint pain, and mood disturbances. Evidence-based guidelines committees disagree over the severity of PLDS. The 2004 International Lyme and Associated Diseases Society (ILADS) concluded that PLDS are severe. The 2006 Infectious Disease Society of America (IDSA) guidelines committee concluded that PLDS are nothing more than the "aches and pains of daily living" and an ad hoc International Lyme group concluded that PLDS are "symptoms common in persons who have never had Lyme disease." Hypothesis Clinical trials validate the severity of persistent Lyme disease symptoms. Evaluation of the Hypothesis There are 22 standardized instruments used to measure the...
A method for detecting electrons emitted as secondary particles by photon incidence to a specimen, as well as a method of using the photons emitted by electron incidence as detecting particles are explained. Pd-Si(100)2{times}1 system is adopted for a case study of using photo-electron spectroscopy where synchrotron emitted light in soft X-ray region is used as the incident light. Pd atoms are deposited little by little on clean Si surface to investigate the electron structure of the surface, and the interface electron structure after bonded formation of Pd(thin film)-Si(substrate) is estimated. Radiation soft X-ray spectroscopy is employed to observe the real state of the bonded interface of Pd(thin film)-Si(substrate) prepared by depositing Pd film in a short period of time. In the case of radiation soft X-ray spectroscopy with electron beam excitation, bonded system of thin film ...
In order to fabricate high temperature superconducting tapes for power applications, the authors have analyzed different buffer layer architectures grown on textured Ni substrates suitable for YBCO deposition. Due to its optimal lattice matching the studied structures present as top layer a CeO{sub 2} film. The deposition of CeO{sub 2} on Ni substrates was performed by pulsed laser ablation and by e-beam evaporation at different temperatures. The films obtained by the two deposition techniques have not optimal structural properties, having a polycrystalline component. The misorientation of CeO{sub 2} is probably due to the formation of NiO at the interface between the film and the substrate during the deposition process even if no oxygen is introduced. In order to prevent Ni oxidation an intermediate 2000 {angstrom} Pd thick film was deposited by e-beam. Furthermore, the lattice mismatch between Pd and CeO{sub 2} is smaller than that between Ni ...
Mechanisms and associated energetics for adatom diffusion on the (100) and (110) surfaces of Ni, Cu, Rh, Pd, and Ag are investigated. Self-diffusion was studied on (100) and (I 10) surfaces of Ni, Cu, Pd and Ag using corrected effective medium method (CEM) and approximation to CEM used for molecular dynamics and Monte Carlo studies (MD/MC-CEM). Self-diffusion on Pd(100), Ag(100), Ni(110), Cu(110), Pd(110), and Ag(110) is accomplished by classical diffusion: the adatom hops from its equilibrium adsorption site over an intervening bridge site to an adjacent equilibrium site. Self-diffusion on Ni(100) and Cu(100) proceeds by atomic-exchange diffusion: the adatom on the surface displaces an atom in the first surface layer. Aside from explicit inclusion of the kinetic-exchange-correlation energy, it is critical to include enough movable atoms in the calculation to insure correct energetics. Distortions ...
Borna disease virus (BDV) uses a unique strategy of replication and transcription which takes place in the nucleus, unlike other known, nonsegmented, negative-stranded RNA viruses of animal origin....Full Text Available
The sequential events and the inflammatory mediators that characterize disease onset and progression of ulcerative colitis (UC) are not well known. In this study, we evaluated the early pathologic events...Full Text Available
BackgroundOne of the more common behavioral manifestations of dementia-related disorders is severe problems with out-of-home mobility. Various efforts have been attempted to attain...Full Text Available
Krabbe disease (KD) is an inherited neurological disorder caused by the deficiency of galactocerebrosidase activity resulting in accumulation of psychosine, which leads to energy depletion,...Full Text Available
The objective of the current research was to examine the association of herd level disease incidence with the return over feed (ROF) (milk income minus feed cost) herd profit index offered through Canwest...Full Text Available
Introduction:Chronic obstructive pulmonary disease (COPD) is a major public health problem. It imparts a substantial economic burden on individuals and society. Acute exacerbations...Full Text Available
Virulent strains of Newcastle disease virus ([NDV] also known as avian paramyxovirus type 1) can be discriminated from low-virulence strains by the presence of multiple basic amino acid residues at...Full Text Available
BackgroundThis study focuses on the role of an Internet-based group for people who have an autoimmune liver disease, primary biliary cirrhosis. Primary biliary...Full Text Available
BackgroundCharacterizing infectious disease burden in Africa is important for prioritizing and targeting limited resources for curative and preventive services and monitoring the...Full Text Available
BackgroundEpidemiological studies have shown a J- or U-shaped relation between alcohol and type 2 diabetes and coronary heart disease (CHD). The underlying mechanisms are not clear....Full Text Available
The abundance of host-seeking Ixodes scapularis nymphs, the principal vector for the Lyme disease agent, Borrelia burgdorferi, in Old Lyme, Lyme, and East Haddam, Connecticut,...Full Text Available
The mouse is the leading organism for disease research. A rich resource of genetic variation occurs naturally in inbred and special strains owing to spontaneous mutations. However, one can also obtain...Full Text Available
Background and objectives: While many patients with end-stage renal disease (ESRD) have impaired physical and psychologic well-being, less is known about these health domains in patients with advanced...Full Text Available
Sugarcane rusts, brown (caused by Puccinia melanocephala) and orange (caused by P. kuehnii), are agronomically important diseases in Florida. Cultivar resistance is the best means of managing these diseases. Unfortunately, natural infection of brown rust is not always efficient in determining resist...
Objectives: To determine the community based prevalence of rheumatic heart disease (RHD) in the rural population of the district of Rahim Yaar Khan in Pakistan.Subjects...Full Text Available
BackgroundPrevention of Chagas disease depends mainly on control of the insect vectors that transmit infection. Unfortunately, the vectors have been resurgent in some areas. It is...Full Text Available
BackgroundAlthough symptoms of sleepiness and fatigue are common among adults with Chronic Kidney Disease (CKD), little is known about the prevalence of these symptoms...Full Text Available
Sexually transmitted diseases (STDs) represent a major public health problem in the country, cause patients enormous suffering, and cost the nation billions of dollars annually. Demographic, sociological,...Full Text Available
Schindler disease is a recently recognized infantile neuroaxonal dystrophy resulting from the deficient activity of the lysosomal hydrolase, alpha-N-acetylgalctosaminidase (alpha-GalNAc). The recent...Full Text Available
Lifetime exposure to physical activity is an important construct for evaluating associations between physical activity and disease outcomes, given the long induction periods in many chronic diseases....Full Text Available
Forty-four patients with histologically proven Hodgkin's disease underwent initial treatment with extended-field radiation therapy. Nineteen of these patients also received combination chemotherapy....Full Text Available
Breast cancer is a progressive and potentially fatal disease that affects women of all ages. Like all progressive diseases, early and reliable diagnosis is the key for successful treatment and annihilation....Full Text Available
The authors’ objective was to analyze the impact of respiratory impairment on the risk of physical functional limitations among adults with chronic obstructive pulmonary disease (COPD)....Full Text Available
Clinical and experimental evidence has demonstrated the potential role of probiotics in the prevention or treatment of inflammatory bowel disease. Probiotic clones with direct immunomodulatory activity...Full Text Available
ObjectivesThe aims of this study were to evaluate the prevalence of otolaryngologic diseases in Korea.MethodsWe obtained data from the 2008 Korea...Full Text Available
BackgroundConducted as part of the Urologic Diseases in America project whose aim was to quantify the burden of urologic diseases on the American public, this study focuses on Veterans...Full Text Available
Eight recreational parks located in a Lyme disease endemic area of southern New York State were surveyed for the presence of ticks during the summer of 1985 by drag sampling. Ixodes dammini, the primary...Full Text Available
Earlier studies of white London busmen revealed that the ischaemic heart disease experience of conductors is better than that of drivers. Various factors which might be related to this difference have...Full Text Available
Physical activity is associated with reduced risk of several age-related diseases as well as with increased longevity in both rodents and humans. Though these associations are well established, evidence...Full Text Available
Background and objectives: Chronic kidney disease (CKD) is associated with impaired physical activity. However, it is unclear whether the associations of physical activity with mortality are modified...Full Text Available
Diseases of man caused by the virus of herpes simplex fall into two broad categories. The primary disease occurs only once in any individual's life and is caused by transmission of virus from an already...Full Text Available
Severe acute respiratory syndrome (SARS) is an infectious disease caused by a novel coronavirus that cost nearly 800 lives. While there have been no recent outbreaks of the disease, the threat...Full Text Available
Organisms in the genus Mycobacterium cause a variety of human diseases. One member of the genus, M. ulcerans, causes a necrotizing skin disease called Buruli ulcer....Full Text Available
The outcome of patients admitted to intensive care units is known to be influenced by such factors as age, previous health status, severity of disease, and diagnosis. To estimate the outcome of such...Full Text Available
Arriving at a firm diagnosis of neurosarcoidosis continues to pose serious problems, particularly when evidence of granulomatous disease outside the nervous system is lacking. The commonest mode of...Full Text Available
BackgroundVariant Creutzfeldt–Jakob disease (vCJD) is a prion disease thought to be acquired by the consumption of prion-contaminated beef products. To date, over 200 cases...Full Text Available
Breath analysis is a powerful noninvasive technique for the diagnosis and monitoring of respiratory diseases, including asthma and chronic obstructive pulmonary disease (COPD). Nitric oxide...Full Text Available
In this paper we report a case with primarily unspecific arthralgia after surgical therapy of hallux valgus deformity and consecutive reflex sympathetic dystrophy in which MR led to the diagnosis of Lyme disease. (orig.)
Bone metastasis of primary colorectal cancer is uncommon. When it occurs, it is usually a late manifestation of disease and is indicative of poor prognosis. We describe a patient with multiple metachronous...Full Text Available
Objectives To understand the perspectives of people with severe chronic obstructive pulmonary disease (COPD) as their illness progresses, and of their informal and professional carers,...Full Text Available
Liver fluke disease is a chronic parasitic inflammatory disease of the bile ducts. Infection occurs through ingestion of fluke-infested, fresh-water raw fish. The most well-known species that cause...Full Text Available
BackgroundApolipoprotein E (ApoE), a cholesterol carrier associated with atherosclerosis, is a major risk factor for Alzheimer's disease (AD). The low-density lipoprotein receptor...Full Text Available
A yellow-pigmented, gram-negative, gliding bacterium isolated from an industrial water spray air humidification system was implicated as a causative agent in several occurrences of lung disease with...Full Text Available
BackgroundSulfasalazine is a widely used anti-inflammatory agent in the treatment of inflammatory bowel disease and several rheumatological disorders. Although as many as 20% of...Full Text Available
Study objectiveThe study aim was to improve our understanding of the relationships between contextual socioeconomic characteristics and coronary heart disease (CHD)...Full Text Available
Stargardt disease (STGD) is the major form of inherited juvenile macular degeneration. Pyridinium bis-retinoid A2E is a major component of lipofuscin which accumulates in retinal pigment epithelium...Full Text Available
BackgroundAlzheimer's disease, known to be associated with the gradual loss of memory, is characterized by low concentration of acetylcholine in the hippocampus and cortex part of...Full Text Available
The identification and validation of biomarkers for diagnosing Alzheimer's disease (AD) and other forms of dementia are increasingly important. To date, ELISA measurement of β-amyloid(1–42),...Full Text Available
Over 200 mutations in the retina specific member of the ATP-binding cassette transporter super-family (ABCA4) have been associated with a diverse group of human retinal diseases....Full Text Available
We describe here seven cases (from five kindreds) of Anderson's disease, which is characterized by diarrhea, steatorrhea, hypobetalipoproteinemia with low levels of cholesterol, triglycerides, and phospholipids,...Full Text Available
Viruses, and more particularly retroviruses, have been postulated to play a role in the pathogenesis of autoimmune diseases. In a search for spumaretrovirus infection markers, we screened a group of...Full Text Available
We have developed a new strategy for immunization of wild rabbit populations against myxomatosis and rabbit hemorrhagic disease (RHD) that uses recombinant viruses based on a naturally attenuated field...Full Text Available
It is now widely accepted that novel infectious disease can be a leading cause of serious population decline and even outright extinction in some invertebrate and vertebrate groups (e.g., amphibians)....Full Text Available
An association of Hirschsprung disease with polydactyly, unilateral renal agenesis, hypertelorism, and congenital deafness is described in sibs (brother and sister) of consanguineous parents. It is...Full Text Available
BackgroundThe long-term goal of the GKDZI (Genetics of Kidney Disease in Zuni Indians) Study is to identify genes, environmental factors, and genetic-environmental...Full Text Available
Though the genetic background of ischaemic and haemorrhagic stroke is often polygenetic or multifactorial, it can in some cases result from a monogenic disease, particularly in young adults. Besides...Full Text Available
Mycobacterium ulcerans is the causative agent of Buruli ulcer, the third most common mycobacterial disease after tuberculosis and leprosy. It is an emerging infectious disease that...Full Text Available
Despite the recent success of genome-wide association studies (GWASs) in identifying loci consistently associated with coronary artery disease (CAD), a large proportion of the genetic components of...Full Text Available
Most human diseases are related in some way to the loss or gain in gene functions. Regulation of gene expression is a complex process. In addition to genetic mechanisms, epigenetic causes are...Full Text Available
A striking common feature of many autoimmune diseases in humans and experimental animals, despite differences in pathology, is that females are highly susceptible to autoimmune conditions compared to...Full Text Available
Few diseases exemplify the integration of research from bench to bedside as well as neonatal lupus, often referred to as a model of passively acquired autoimmunity. In essence, this disease encompasses...Full Text Available
Southern tick-associated rash illness (STARI) is a Lyme disease-like infection described in patients in the southeastern and south-central United States, where classic Lyme disease is relatively rare....Full Text Available
Two infants were seen with severe ascites detected before birth, a previously unreported presentation of Niemann-Pick disease type C. In the second infant no diagnostic storage cells were present in...Full Text Available
BackgroundExcessive television (TV) viewing might play an important role in the development of cardiovascular disease (CVD). The aim of this study was to examine the independent...Full Text Available
BackgroundA goal of human genetics is to discover genetic factors that influence individuals' susceptibility to common diseases. Most common diseases are thought to result from the...Full Text Available
OBJECTIVE--To develop, test, and validate an algorithm for diagnosing disease in neonates during an over the telephone referral to a specialist cardiac centre. DESIGN--A draft algorithm requiring only...Full Text Available
ObjectivesThe aim of this study was to investigate the effect of cigarette smoking on clinical parameters and signs anemia of chronic disease in chronic periodontitis patients.Full Text Available
Erythrocyte transketolase activity and the effect of adding thiamine pyrophosphate (% thiamine pyrophosphate effect) were measured in 111 subjects suspected to suffer from Leigh's disease (subacute...Full Text Available
A conference entitled ‘2nd International Berlin Bat Meeting: Bat Biology and Infectious Diseases’ was held between the 19 and 21 of February 2010 in Berlin, Germany. Researchers from...Full Text Available
The effects of dietary monosodium glutamate (MSG) on trans-fatty acid (TFA)-induced nonalcoholic fatty liver disease (NAFLD) are addressed in an animal model. We used Affymetrix microarray...Full Text Available
Periodontal diseases are infections of the tissues supporting the dentition. Recognition that relatively specific microfloras are associated with distinct clinical forms of periodontal disease has prompted...Full Text Available
Objective:To investigate the combined effect of both pioglitazone and methotrexate on disease activity of rheumatoid arthritis in a biphasic study; experimental and clinical.Methods:Experimentally:...Full Text Available
BackgroundChronic wasting disease (CWD) of cervids is a prion disease distinguished by high levels of transmissibility, wherein bodily fluids and excretions are thought to play an...Full Text Available
Many epidemiological evidences have proven the association between smoking and periodontal disease. The causality can be further established by linking findings of traditional epidemiological studies...Full Text Available
Background:We analyzed the effects of a docosahexaenoic acid (DHA) supplementation in patients affected with late onset Stargardt disease (STGD).Methods:DHA...Full Text Available
Since polyglutamine (polyQ) aggregate formation has been implicated as playing an important role in expanded CAG repeat diseases, it is important to understand the biophysics underlying the...Full Text Available
Huntington's disease (HD) is one of several neurodegenerative disorders caused by expansion of CAG repeats in a coding gene. Somatic CAG expansion rates in HD vary between organs, and the greatest instability...Full Text Available
Enterotoxigenic Escherichia coli (ETEC) is a leading cause of diarrhea in travelers to countries where the disease is endemic and causes a major disease burden in the indigenous population,...Full Text Available
Paratuberculosis (Johne's disease), an endemic mycobacteriosis of cattle that is caused by Mycobacterium paratuberculosis, is characterized by incoercible diarrhea and fecal shedding of bacteria. The...Full Text Available
Coronary artery disease (CAD) is the single most common cause of death in the developed world, responsible for about 1 in every 5 deaths. The morbidity, mortality, and socioeconomic importance...Full Text Available
This study examined the genetic basis of hypertension and renal disease in Dahl SS/Mcwi (Dahl Salt-Sensitive) rats using a complete chromosome substitution panel of consomic rats in which each of the...Full Text Available
Characteristics relevant to cardiovascular disease, including anthropometry, arterial blood pressure, serum cholesterol levels, chest radiography and electrocardiography, were investigated in a survey...Full Text Available
Hepatocellular carcinoma (HCC) is one of the most critical global health issues. With frequent association of viral liver disease, HCC is highly complex, harboring both cancer and chronic liver disease....Full Text Available
This study was designed to identify the causes of the development of carpal tunnel syndrome (CTS) associated with end stage kidney disease (ESKD). A total of 112 patients with ESKD, 64 on hemodialysis...Full Text Available
BackgroundIn 1988, the SPILI project was established in order to evaluate the cardiovascular disease (CVD) risk profile of the inhabitants of Spili, in rural Crete, Greece. The first...Full Text Available
Alterations in basement membrane components, notably proteoglycans, in a rat model of polycystic kidney disease have been investigated. Rats were fed phenol II (2-amino-4-hydroxyphenyl-5-phenyl thiazole)...Full Text Available
Public health activities, especially infectious disease control, depend on effective teamwork. We present the results of a pilot audit questionnaire aimed at assessing the quality of public health services...Full Text Available
To assess the effects of increasing the mineral content of parenteral nutrition solutions on the biochemical and radiological indicators of metabolic bone disease of prematurity 27 neonates who required...Full Text Available
BackgroundSepsis or bacteraemia, however rare, is a significant cause of high mortality and serious complications in children. In previous studies skin disease or skin infections...Full Text Available
Background:Erectile dysfunction in type-2 diabetes may be an independent marker for coronary artery disease. Present study was undertaken to investigate whether type-2 diabetic...Full Text Available
BackgroundMutations of the amyloid precursor protein gene (APP) are found in familial forms of Alzheimer's disease (AD) and some lead to the elevated production...Full Text Available
Anxiety may cause adverse outcomes through physiologic pathways in patients with cardiac disease. The purpose of this dissertation was to investigate anxiety and its correlates in persons with acute myocardial infarction (AMI) and heart failure (HF). The ...
The two categories of anti-albumin antibodies (AAA), namely precipitins (AA-P) and agglutinins (AA-Aggl), were investigated in 260 patients with morphologically diagnosed chronic liver diseases (CLD)....Full Text Available
BackgroundWhile some studies have found that anger increases the risk of incident coronary heart disease (CHD), others found anger protective. Prior studies did not...Full Text Available
AIM: This paper reviews progression in renal diseases. METHODS: An English language literature search using Medline (1980 January-2001 July) was done to assess research and review articles on progression...Full Text Available
BackgroundWidespread availability of geographic information systems software has facilitated the use of disease mapping in academia, government and private sector. Maps that display...Full Text Available
Background. Erythropoietin deficiency and anemia occur in Chronic Kidney Disease (CKD) and may be treated with Erythropoietin Stimulating Agents (ESAs). The optimal hemoglobin,...Full Text Available
MRI plays an increasingly important role for assessment of patients with chronic liver disease. MRI has numerous advantages, including lack of ionizing radiation and the possibility of performing...Full Text Available
BACKGROUND--Interstitial lung diseases are characterised by the recruitment of mononuclear cells to disease sites where maturation occurs and activation products, including lysozyme (LZM), are released....Full Text Available
BackgroundChronic kidney disease and end-stage renal disease are major causes of morbidity and mortality that are seen far more commonly in the aged population. Interestingly, kidney...Full Text Available
BackgroundTraditionally in pediatric HIV, the CD4+ T-lymphocyte percent is used in monitoring disease progression due to the variability in absolute CD4+ T-lymphocyte...Full Text Available
A form for the clinical evaluation of bovine digital disease was developed. In this article, each section of the resulting Digit Evaluation Form is discussed and justified. By following the...Full Text Available
OBJECTIVE: To assess the association between erectile dysfunction (ED) and the long-term risk of coronary artery disease (CAD) and the role of age as a modifier of this association.PARTICIPANTS...Full Text Available
This work studied the effect of the nature of the metal on the performance of Co/CeO{sub 2}, Pd/CeO{sub 2} and Pt/CeO{sub 2} catalysts in the partial oxidation of ethanol. Infrared spectroscopy of adsorbed ethanol and temperature programmed desorption of ethanol were performed in order to establish the reaction mechanism. Catalytic experiments revealed that the product distribution is strongly affected by the nature of the metal. Acetaldehyde was practically the only product formed on a Co/CeO{sub 2} catalyst while methane was also produced on Pt/CeO{sub 2} and Pd/CeO{sub 2} catalysts. These results were explained through a reaction mechanism proposed by the characterization techniques. Co/CeO{sub 2} and Pt/CeO{sub 2} catalysts show mainly ethoxy species at room temperature whereas acetate species is mainly formed on the Pd/CeO{sub 2} catalyst. The ethoxy species can undergo further dehydrogenation and desorb as ...
New tetradentate N(2)O(2) donor Schiff bases and their mononuclear Co(II), Ni(II), Cu(II), and Pd(II) complexes were synthesized and characterized extensively by IR, (1)H-, (13)C-NMR, mass, ESR, conductivity measurements, elemental and thermal analysis. Specifically the magnetic and electronic spectral measurements demonstrate the octahedral structures of cobalt(II), nickel(II) complexes and square planar geometries of copper(II), palladium(II) complexes. All the ligands and complexes were screened for their in vitro antibacterial activity against two gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus) and two gram-negative bacteria (Escherichia coli, Klebsiella pneumonia). In this study, Pd(II) complexes exhibited potent antibacterial activity against B. subtilis, S. aureus whereas other metal complexes also exerted good activity towards all tested strains even than standard drugs streptomycin and ampicillin. PMID:21297294
The available experimental data on the specific heat, magnetic susceptibility, magnetization, valence, NMR Knight shift and relaxation rate, and the quadrupolar moment of YbPd_2Si_2 are examined within the framework of the single-ion Anderson model. Such an analysis has previously given excellent agreement between theory and experiment for numerous other light heavy-fermion compounds, where crystalline fields do not play a dominant role. For YbPd_2Si_2, substantial crystalline-field splittings make difficult a quantitative comparison with existing exact solutions of the Anderson model. Inconsistencies with the interpretation that a nearly degenerate ground quadruplet determines the low-temperature thermodynamics are pointed out. It is concluded that at least three of the four Kramers doublets participate in the low-T properties. These three doublets should have a splitting of the order of the Kondo temperature, i.e., about 100 K. A simple ...
The available experimental data on the specific heat, magnetic susceptibility, magnetization, valence, NMR Knight shift and relaxation rate, and the quadrupolar moment of YbPd{sub 2}Si{sub 2} are examined within the framework of the single-ion Anderson model. Such an analysis has previously given excellent agreement between theory and experiment for numerous other light heavy-fermion compounds, where crystalline fields do not play a dominant role. For YbPd{sub 2}Si{sub 2}, substantial crystalline-field splittings make difficult a quantitative comparison with existing exact solutions of the Anderson model. Inconsistencies with the interpretation that a nearly degenerate ground quadruplet determines the low-temperature thermodynamics are pointed out. It is concluded that at least three of the four Kramers doublets participate in the low-{ital T} properties. These three doublets should have a splitting of the order of the Kondo temperature, i.e., ...
Two new equiatomic ternary compounds, EuPtSi and EuPdSi, have been synthesized and are found to crystallize in the cubic LaIrSi type structure. The magnetic susceptibility of both compounds follows Curie-Weiss behavior in the temperature range 10 to 300 K with an effective magnetic moment close to that of Eu"2"+ moment. The paramagnetic Curie temperatures are 5 K for EuPtSi and 9 K for EuPdSi. There is no clear indication of magnetic ordering in the susceptibility of both the compounds down to 4.2 K. However, "1"5"1Eu Moessbauer studies show a hyperfine split pattern in EuPtSi at 4.2 K indicating the onset of magnetic ordering. The "1"5"1Eu isomer shifts are temperature independent and are characteristic of the divalent Eu ion. All these results establish that the Eu ions are in a stable divalent state in these compounds. (orig.).
We report the results of neutron-diffraction experiments on CeM_2Si_2 (M = Ag,Au,Pd,Rh) which were performed to explore the role of valence fluctuations and 4f hybridization in the magnetic ordering of cerium compounds. All four order antiferromagnetically, the first three exhibiting structures consisting of ferromagnetic layers with moments perpendicular to the layers, which are believed to be characteristic of 4f-4f interactions mediated through hybridization with conduction electrons. CePd_2Si_2 has an anomalously small moment (0.62#mu#/sub B/) in the ordered state. CeAg_2Si_2 exhibits an incommensurate longitudinal, static magnetization wave with moment and propagation direction along the a axis. The fourth compound, CeRh_2Si_2, has the highest known transition temperature (39 K) reported for cerium ordering; it exhibits another second-order transition at 27 K to a complex commensurate structure with modulated moments. The results are ...
We report the results of neutron-diffraction experiments on CeM/sub 2/Si/sub 2/ (M = Ag,Au,Pd,Rh) which were performed to explore the role of valence fluctuations and 4f hybridization in the magnetic ordering of cerium compounds. All four order antiferromagnetically, the first three exhibiting structures consisting of ferromagnetic layers with moments perpendicular to the layers, which are believed to be characteristic of 4f-4f interactions mediated through hybridization with conduction electrons. CePd/sub 2/Si/sub 2/ has an anomalously small moment (0.62..mu../sub B/) in the ordered state. CeAg/sub 2/Si/sub 2/ exhibits an incommensurate longitudinal, static magnetization wave with moment and propagation direction along the a axis. The fourth compound, CeRh/sub 2/Si/sub 2/, has the highest known transition temperature (39 K) reported for cerium ordering; it exhibits another second-order transition at 27 K to a complex commensurate structure ...
Excellent silicided shallow p{sup +}n junctions have been successfully achieved by the implantation of BF{sub 2}{sup +} ions into thin Pd{sub 2}Si films on Si substrates to a dose of 5 {times} 10{sup 15} cm{sup {minus}2} and subsequent low temperature (even at 550 C) furnace annealing. The formed junctions have been characterized for respective implantation conditions. In this experiment, the implant energy is the key role in obtaining a low leakage diode. Reverse current density of about 3 nA/cm{sup 2} and an ideality factor of about 1.05 can be attained by the implantation of BF{sub 2}{sup +} ions at 80 keV and subsequent annealing at 550 C. The junction depth is about 0.09 {mu}m, measured by the spread resistance method. As compared with the results of unimplanted specimens, the implantation of BF{sub 2}{sup +} ions into a thin Pd{sub 2}Si layer can stabilize the silicide film and prevent it from forming islands during high temperature ...
In order to improve the long term reliability of lead-salt diode lasers, ohmic contacts of multilayer, thin-film structures consisting of In plus Au, Pt, Ni, and Pd have been studied. Diode lasers of PbSnTe fabricated with a variety of contacts were tested during room-temperature storage and during accelerated aging tests. The results show that contact reliablility can be improved when multiple overlapping films are used. After 4500 h of baking at 60 /sup 0/C, lasers with In-Au-Pd-Au contacts on both sides showed the least resistance increase (10%). For lasers with In-Au-Pt-Au contacts, 1 h of baking at 60 /sup 0/C is equivalent to 2 d storage at room temperature. Extrapolating these results, a 70% increase in contact resistance is expected for this type of laser after 9000 d of storage at room temperture. Our data also suggests that a smaller increase in contact resistance can be expected for lasers fabricated with In-Au-Ni-Au and ...
The growth of epitaxial MnO(100) and MnO(111) layers on Pd(100) surface has been investigated by spot-profile analysis low-energy electron diffraction, dynamic atomic force microscopy, photoemission and high-resolution electron energy loss spectroscopy, and density functional theory. We have found that despite the large lattice mismatch to the Pd(100) substrate, the MnO(100) layers are kinetically stabilized at low temperatures (?350 deg. C) and at oxygen pressures between 2x10-7 and 5x10-7 mbar. Annealing in ultrahigh vacuum at 650 deg. C or, alternatively, deposition of manganese metal in oxygen pressure -7 mbar causes the transformation of the MnO(100) to a polar MnO(111) surface, which is decorated by triangular pyramids with (100) side facets. It is suggested that the growth of MnO(111) layers is energetically preferred over MnO(100) due to the epitaxial stabilization at the metal-oxide interface.
Eu 4f electronic structures of a temperature-induced valence transition system EuPd{sub 2}Si{sub 2} have been investigated by bulk-sensitive high-resolution photoemission spectroscopy at temperatures from 20 to 300 K. The bulk Eu{sup 2+} 4f component is definitely distinguished from two surface Eu{sup 2+} 4f components. The changes in the spectral intensity of the bulk Eu{sup 2+} and Eu{sup 3+} 4f configurations and in the energy separation between these states are observed in the temperature dependent photoemission spectra. These temperature dependences are related to the valence transition of EuPd{sub 2}Si{sub 2}. The Eu mean valence is evaluated to be 2.75{+-}0.03 at 20 K and 2.30{+-}0.05 at 300 K. These values are in good agreement with those evaluated from Moessbauer and Eu L{sub III}-edge X-ray absorption measurements.
We report here a new approach to introduce the effect of chemisorption in the Monte-Carlo simulation procedure for studying the segregation behaviour in bimetallic nanoparticles at low pressures. A coordination-dependent pair interaction energy is constructed in terms of partial bond energies and the exchange energy where the partial bond energy can be empirically calculated from the experimental values of dimer energy, the pressure-dependent surface energy and the bulk cohesive energy of the constituent metals. The advantage of this procedure is the ability to estimate the pressure-dependent surface composition of the nanoparticles. The method has been applied to oxygen-adsorbed Pd-Ag systems; and it is found that while Ag segregate in clean particles, at higher oxygen pressures Pd atoms segregate to the surface. The present technique has been argued to be suitable for higher pressures (>10-5Torr) when coverage cannot be accurately ...
With "1"5"1Eu-Moessbauer spectroscopy and other methods the complex magnetic properties of Eu_2PdSi_3, arising from the two crystallographically different lattice sites of the Eu"2"+ ions, have been already studied. Here we study the impact of magnetic dilution of the magnetic Eu"2"+ sites by non-magnetic Y"3"+ ions. A previous specific heat study has found reduced magnetic ordering temperatures with strong indication of disorder effects like in magnetic spin glasses. Here we provide from "1"5"1Eu-Moessbauer spectroscopy detailed information of the impact of Y"3"+ substitution on the magnetic properties of the two lattice sites, well distinguishable in the "1"5"1Eu-spectra. Since the substitution of the larger Eu"2"+ ions by the smaller Y"3"+ ions is connected with a lattice contraction, we also applied high pressure to the Eu_2PdSi_3 sample and observed drastic changes in the magnetic properties originating from a valence transition towards ...
Radiological findings of chest and abdominal wall involvement in Hodgkin's disease are reported. This manifestation was diagnosed in one patient in the primary staging and in two patients during the course of the disease. Typical radiological findings are soft tissue masses in the chest and abdominal wall, in two cases with continous tumor growth of enlarged mediastinal lymphnodes into the anterior chest wall. The axial computed tomography is the best method to evaluate the extent of chest and abdominal wall involvement in Hodgkin's disease.
The objective of this animation is to develop a QTL mapping population for locating and characterizing the genes responsible for resistance to tan spot disease of wheat.
Acquired cystic kidney disease (ACKD), also known as acquired renal cystic disease (ARCD,) occurs in patients who are on dialysis for end-stage renal disease. It is generally accepted that ACKD develops as a consequence of sustained uremia and can first manifest even before dialysis is initiated while the patient is still in chronic renal failure. The role of immune suppression, particularly in transplant recipients, in the development of ACKD, is still under investigation. The prevalence of ACKD is directly related to the duration of dialysis and the risk of cancer is directly related to the presence of cysts. Herein we review the current understanding of the pathophysiology and imaging implications of ACKD. (orig.)
In 15 children (in age 2 weeks - 15 years) the computer tomography beside radiological examination was done because of mediastinal diseases. In all cases the computer tomography was valuable. In 4 cases obtained results have changed diagnostic conclusions. The examples are described showing the usefulness of the computer tomography as supplementary diagnostic method in mediastinal diseases in children.
Background/AimsFabry disease is an X-linked recessive and progressive disease caused by α-galactosidase A (α-GaL A) deficiency. We sought to assess the prevalence...Full Text Available
Pneumococcal disease in young children has not been as well characterized in East Africa as it has been in industrialized countries. Although pneumococci are likely to cause substantial mortality...Full Text Available
...INFORMATION Diarrhoeal disease Food safety and foodborne illness Enterohaemorrhagic Escherichia coli (EHEC) Cholera WHO PROGRAMMES AND ACTIVITIES Child and Adolescent Health and Development (...FOS) Initiative for Vaccine Research (IVR) TECHNICAL INFORMATION Vaccine research: diarrhoeal diseases Cholera Water-related diseases Household water treatment and safe storage WHO Global Salm-Surv ...PUBLICATIONS Diarrhoea: child and adolescent health Diarrhoea: cholera RELATED TOPICS - Child health - Water - Food safety - Cholera - Travel - Breastfeeding ...
... All rickettsial diseases respond to treatment with antibiotics such as doxycycline and tetracycline As of 10 May, the Government of South Africa has reported 186 confirmed cases of RVF in humans, including 18 deaths, in Free State Province, Eastern Cape Province, Northern Cape Province, Western Cape, and North West Province. RVF is a viral disease that primarily affects animals (such as cattle, buffalo, sheep, goats and camels). The disease can also affect humans. The main mode of transmission of RVF ...
In diabetes complications, CCN-2 (known originally as CTGF) has been implicated in diabetic nephropathy both as a marker and a mediator of disease. This commentary addresses CCN-2 in diabetic nephropathy, in the context of the recent publication of the first human study to inhibit CCN-2 bioactivity in diabetic kidney disease.
With reference to three hypotheses on the causes of forest decline, the manifold uses of forest decline surveys are demonstrated. Hypothesis no. 1: Forest disease from high-voltage transmission lines; hypothesis no. 2: Forest disease as the consequence of damage from micorrhizas; hypothesis no. 3: Radioactivity as the cause of the increased incidence of forest disease. (orig./MG)
In-situ TEM investigations during thermal treatment of amorphous Pd{sub 81}Si{sub 19} have been performed. It was found that crystalline nuclei are formed near the perforation edge of the hole produced by electrochemical polishing. After impinging with neighboring crystals, a crystallization front formed which was aligned parallel to the perforation edge. The crystallization front moved in the direction perpendicular to the perforation edge. Crystal growth was found to proceed faster in thinner parts of the specimen than in thicker parts. The results are described qualitatively within a thermodynamic model taking into account volume-, surface- and interfacial free energies and an appropriate specimen geometry.
The magnetic ordering temperature of some rare-earth-based heavy-fermion compounds is strongly pressure dependent and can be completely suppressed at a critical pressure, p{sub c}, making way for novel correlated electron states close to this quantum critical point. We have studied the clean heavy-fermion antiferromagnets CePd{sub 2}Si{sub 2} and CeIn{sub 3} in a series of resistivity measurements at high pressures up to 3.2 GPa and down to temperatures in the mK region. In both materials, superconductivity appears in a small window of a few tenths of a GPa on either side of p{sub c}. We present detailed measurements of the superconducting and magnetic temperature-pressure phase diagram, which indicate that superconductivity in these materials is enhanced, rather than suppressed, by the closeness to magnetic order. (author)
The magnetic ordering temperature of some rare-earth-based heavy-fermion compounds is strongly pressure dependent and can be completely suppressed at a critical pressure, p_c, making way for novel correlated electron states close to this quantum critical point. We have studied the clean heavy-fermion antiferromagnets CePd_2Si_2 and CeIn_3 in a series of resistivity measurements at high pressures up to 3.2 GPa and down to temperatures in the mK region. In both materials, superconductivity appears in a small window of a few tenths of a GPa on either side of p_c. We present detailed measurements of the superconducting and magnetic temperature-pressure phase diagram, which indicate that superconductivity in these materials is enhanced, rather than suppressed, by the closeness to magnetic order. (author)
In the first paper of this series devoted to a structural analysis of a binary metallic glass model, we study a Pd/sub 80/Si/sub 20/ sample obtained by numerical relaxation. We discuss the reproducibility of the method and make a comparison with the experimental interference functions. Then we undertake a microscopic structural analysis from several point of view: we first study the number of neighbours of each type for each type of atoms; secondly, we analyse the structure by means of the radical plane method; at last, we show that it is possible to generalize the five fundamental characteristic units introduced by Bernal, so that we can define the environment of any Si atom without any ambiguity. All these methods reveal a certain tendency towards a prismatic environment for the metalloids.
Specimens of glassy Pd{sub 80}Si{sub 20} were irradiated at temperatures below 100K with 3.5 MeV krypton ions. After irradiation, changes in the sound velocity were measured at 80 K without warm-up by Brillouin scattering. The sound velocity decreased with increasing ion fluence and exponentially approached a saturation value of -4.7%. The change in the shear elastic modulus per unit concentration n of defects was estimated to be d(ln C)/dn = -9.4 to -4.7. The results of the present study are compared with changes in the elastic properties predicted recently by an interstitialcy model for glassy metals, and with the elastic properties of glassy metals after thermal treatment.
We have performed polarized neutron diffraction measurements on the intermediate valence compound CePd{sub 3} using the D3 spectrometer at the ILL. The results show that at low temperatures, 1.7 K, as well as at 100 K, the field-induced magnetic amplitudes measured in a field of 4.6 T could be interpreted in terms of two contributions: a 4f-type contribution with a Ce{sup 3+} form factor, and an extra delocalized contribution (relatively narrow in q-extent). In particular, we find that the values of the 4f moment deduced from the extrapolation of the neutron data to Q=0 are systematically lower than the values deduced from bulk magnetization measurements performed on the same sample. This difference can be ascribed to a possible positive polarization of the conduction band which is similar at both temperatures.
This paper describes the search for new potential chemotherapeutic agents based on transition metal complexes with planar ligands. In this study, palladium polypyridyl complexes were synthesized and characterized by elemental analysis, NMR, UV-VIS and IR spectroscopies. The interaction of the complexes with DNA was also investigated by spectroscopic methods. All metal-to-ligand charge transfer (MLCT) bands of the palladium polypyridyl complexes exhibited hypochromism and red shift in the presence of DNA. The binding constant and viscosity data suggested that the complexes [PdCl{sub 2}(phen)] and [PdCl{sub 2}(phendiamine)] interact with DNA by electrostatic forces. Additionally, these complexes induced an important leishmanistatic effect on L. (L.) mexicana promastigotes at the final concentration of 10 {mu}mol L{sup -1} in 48 h. (author)
The solid solutions Eu(Ir_1_-_xPd_x)_2Si_2, which exist for 0#<=#x#<=#0.125 and 0.75#<=#x#<=#1, cristallize with the tetragonal ThCr_2Si_2-type structure. The variation of the europium valence with composition has been thoroughly studied at temperatures 4.2#<=#T#<=#293 K by "1"5"1Eu Moessbauer resonance. For 0#<=#x#<=#0.125 the europium valence at room temperature decreases as x increases. For 0.75#<=#x#<=#1 the valence transition temperature Eu"3"+#->#Eu"2"+ increases as x increases. (orig.).
Changes in mass density of amorphous Pd{sub 80}Si{sub 20} were monitored in situ during irradiation with He{sup 2+} and H{sup +} ions at temperatures below 100 K and during subsequent thermal treatment. The mass density decreased with increasing ion fluence and exponentially approached a saturation value of -1.2%, corresponding to a recombination volume of 190 atomic volumes. The initial swelling rate was 2.3 atomic volumes/displaced atom. The mass density of the irradiated material increased during subsequent thermal treatment, and the irradiation-induced decrease of the mass density recovered completely at room temperature.
The compound GdPd{sub 2}Si, which is reported to order antiferromagnetically at 13 K, has been investigated by heat capacity and electrical resistivity measurement in the presence of external magnetic fields. In contrast to an earlier report, the zero-field heat capacity and resistivity data indicate two magnetic transitions at 13 and 17 K. The external magnetic field substantially influences the resistivity and heat capacity of the compound around the magnetic ordering temperature. The magnetocaloric effect, which is calculated from in-field heat capacity data, is quite large around the magnetic transition temperature. The magnetoresistance is also large near the magnetic ordering temperature. The metamagnetic transition is observed for 10 kOe magnetic field both in magnetocaloric and in magnetoresistance data. The metamagnetic transition strongly influences the magnetocaloric effect and magnetoresistance, which is large in this compound. (author). ...
The compound GdPd_2Si, which is reported to order antiferromagnetically at 13 K, has been investigated by heat capacity and electrical resistivity measurement in the presence of external magnetic fields. In contrast to an earlier report, the zero-field heat capacity and resistivity data indicate two magnetic transitions at 13 and 17 K. The external magnetic field substantially influences the resistivity and heat capacity of the compound around the magnetic ordering temperature. The magnetocaloric effect, which is calculated from in-field heat capacity data, is quite large around the magnetic transition temperature. The magnetoresistance is also large near the magnetic ordering temperature. The metamagnetic transition is observed for 10 kOe magnetic field both in magnetocaloric and in magnetoresistance data. The metamagnetic transition strongly influences the magnetocaloric effect and magnetoresistance, which is large in this compound. (author). Letter-to-the-editor
The magnetic susceptibility of the ternary compounds, RPd/sub 2/Si/sub 2/ (where R=Gd, Tb, Dy, Ho and Er) has been measured. GdPd/sub 2/Si/sub 2/ and TbPd/sub 2/Si/sub 2/ order antiferromagnetically at 13 and 20 K respectively; the rest of the compounds do not show clear ordering down to 4.2 K. Palladium carries no moment in these compounds. The De Gennes formula is not obeyed indicating that the exchange interaction between the 4f moments via conduction electrons is not isotropic.
The cross-over from a magnetically ordered to a non-magnetic spin liquid state has been investigated in a series of resistance measurements under hydrostatic pressures of up to 30 kbar and at temperatures down to below 200 mK in the heavy fermion antiferromagnet CePd{sub 2}Si{sub 2}. The electrical resistivity changes dramatically with increasing pressure. Near the critical pressure, at which the magnetic ordering temperature is extrapolated to zero, it exhibits a quasi-linear variation over two orders of magnitude in temperature. This non-Fermi liquid form of {rho}(T) extends down to the onset of a new superconducting transition below 430 mK. (orig.).
The cross-over from a magnetically ordered to a non-magnetic spin liquid state has been investigated in a series of resistance measurements under hydrostatic pressures of up to 30 kbar and at temperatures down to below 200 mK in the heavy fermion antiferromagnet CePd_2Si_2. The electrical resistivity changes dramatically with increasing pressure. Near the critical pressure, at which the magnetic ordering temperature is extrapolated to zero, it exhibits a quasi-linear variation over two orders of magnitude in temperature. This non-Fermi liquid form of #rho#(T) extends down to the onset of a new superconducting transition below 430 mK. (orig.).
We present the results of the low-temperature specific heat of Kondo compound Ce{sub 3-x}La{sub x}Pd{sub 20}Si{sub 6} (x=0, 1, 2 and 2.7) and its magnetic-field dependence for x=0. The magnetic part of specific heat divided by temperature, C{sub m}/T, for x=0 makes a peak as high as 9 J/mol Ce K{sup 2} at 0.2 K. On the other hand, C{sub m}/T for the other x`s keeps increasing monotonically below 0.2 K and the Fermi-liquid ground state is not realized even in diluted samples. It was found that the magnetic field strongly depresses C{sub m}/T at low temperatures. (orig.).
We present the results of the low-temperature specific heat of Kondo compound Ce_3_-_xLa_xPd_2_0Si_6 (x=0, 1, 2 and 2.7) and its magnetic-field dependence for x=0. The magnetic part of specific heat divided by temperature, C_m/T, for x=0 makes a peak as high as 9 J/mol Ce K"2 at 0.2 K. On the other hand, C_m/T for the other x's keeps increasing monotonically below 0.2 K and the Fermi-liquid ground state is not realized even in diluted samples. It was found that the magnetic field strongly depresses C_m/T at low temperatures. (orig.).
Internal friction of amorphous Pd/sub 80/Si/sub 20/ metal doped with hydrogen or deuterium was measured with a specially designed apparatus using amorphous metal sheet as a part of the electric oscillating circuit. Two peaks in Q/sup -1/ curve are observed. Applying the peak shift method to the first Snoek-like peak, we can determine the relaxation time from which the microdiffusion coefficient can be calculated. The obtained microdiffusion coefficient is about 10/sup -14/ m/sup 2//s at 200 K, being comparable with the macrodiffusion coefficient obtained from the releasing method. It can, however, not elucidate the hydrogen isotopic effect on the peak temperature of Q/sup -1/ curve, the activation energy for relaxation and the relaxation time from the present work because of the broadness of obtained Q/sup -1/ curve.
Pd/n-Si and Pd/n-GaAs devices have been irradiated from high energy ({approx}100 MeV) heavy ions of Au{sup 7+} (gold) and Si{sup 7+} (silicon) to study the irradiation effects in these junction devices on semiconductor substrates. The devices have been characterized from I-V and C-V studies for electronic flow characterization. It has been found that the devices become high resistive on the irradiation and the substrates change the conductivity type from n- to p- on the irradiation of fluence of {approx}10{sup 12}-10{sup 13} ions/cm{sup 2}. The change in conductivity type has been understood as a result of creation of deep acceptors on the irradiation.
An x-ray diffraction technique for determining thin-film thickness is presented which should prove to be a valuable alternative to the array of spectroscopies (Rutherford backscattering spectrometry, Auger electron spectroscopy, etc.) currently favored for these measurements. Some of the virtues of this x-ray diffraction approach are its nondestructive nature, fast data acquisition rate (enabling in situ observations), thickness resolution better than 5 nm, and conventional equipment requirements. Results are shown for Pd/sub 2/Si thin films grown during isothermal annealing of Pd coatings (100 nm) on Si at 200 /sup 0/C for various amounts of time. A comparison of these x-ray measurements with Rutherford backscattering spectrometry data taken from the same specimens is used to demonstrate the validity of the x-ray technique.
The magnetic susceptibility and high-field magnetization have been measured for the intermediate valence system Eu(Pd_1_-_xPt_x)_2Si_2 with 0#<=#x#<=#0.15. A first-order valence transition is observed for all the compounds under high field of 100 T at low temperatures. This valence transition is of first order accompanied with a large hysteresis, which is in contrast to a continuous valence change against temperature. Based on the interconfigurational fluctuation (ICF) model, the temperature- and field-induced valence transitions are discussed. It is found that a first-order valence transition can be induced by magnetic field, even if the system shows a continuous valence transition against temperature. Metamagnetic behavior at finite temperatures is also understood qualitatively by the ICF model. copyright 1997 The American Physical Society.
The electronic structures of platinum group elements (Ru, Os, Rh, Ir, Pd, and Pt) silicides have been calculated. Ir{sub 3}Si{sub 5} is a semiconductor with the direct gap of 1.14 eV. Among monosilicides, RuSi and OsSi with the FeSi-type structure are semiconductors with the gap values of 0.21 and 0.41 eV but RhSi, IrSi, PdSi, and PtSi with the MnP-type structure are metals. No semiconducting compounds can be found in other platinum group elements silicides other than known Ru{sub 2}Si{sub 3}, Os{sub 2}Si{sub 3}, and OsSi{sub 2}.
The electronic structures of platinum group elements (Ru, Os, Rh, Ir, Pd, and Pt) silicides have been calculated. Ir_3Si_5 is a semiconductor with the direct gap of 1.14 eV. Among monosilicides, RuSi and OsSi with the FeSi-type structure are semiconductors with the gap values of 0.21 and 0.41 eV but RhSi, IrSi, PdSi, and PtSi with the MnP-type structure are metals. No semiconducting compounds can be found in other platinum group elements silicides other than known Ru_2Si_3, Os_2Si_3, and OsSi_2.
Thin Pt, Pd, Pt/sub 2/Si, PtSi, Pd/sub 2/Si, Ni, Mo, W, Nb, Ti, V films deposited on Si single crystal were treated by using electron beam pulses of 60 ns duration in the 0.4-4 J/cm/sup 2/ energy density range. Irradiation of these structures produces at the same time many phases. Post-thermal annealing of the reacted layer induces the formation of a stable phase, the same obtained by only thermal treatment in a conventional furnace. A linear relationship between the energy density range and the lowest eutectic temperature of the compounds formed has been found. Further SEM observations seem to identify a liquid layer from which the phases are forming by subsequent fast cooling.
Thin Pt, Pd, Pt_2Si, PtSi, Pd_2Si, Ni, Mo, W, Nb, Ti, V films deposited on Si single crystal were treated by using electron beam pulses of 60 ns duration in the 0.4-4 J/cm"2 energy density range. Irradiation of these structures produces at the same time many phases. Post-thermal annealing of the reacted layer induces the formation of a stable phase, the same obtained by only thermal treatment in a conventional furnace. A linear relationship between the energy density range and the lowest eutectic temperature of the compounds formed has been found. Further SEM observations seem to identify a liquid layer from which the phases are forming by subsequent fast cooling. (author).
The intermediate valent behaviour of YbPd_2Si_2 has been studied under pressure in the temperature range from 1.2 K to 90 K by using the 84 keV Moessbauer transition in "1"7"0Yb. At 54 kbar and 4.2 K we obtain an increase of the electric field gradient (EFG) by a factor of #approx =# 3. In addition, the EFG varies strongly with temperature, in contrast to the behaviour at ambient pressure. At 1.2 K a change of the hyperfine pattern is observed indicating a magnetic character of the Yb ion. These results provide evidence of a pressure induced change of the valence state close to 3+. (orig.).
The structure and catalytic properties of 2 wt.-% Pd/SiO/sub 2/ catalysts promoted with 2 wt.-% MgO and 0.2-5 wt.-% iron have been investigated. Catalysts were characterized by TPR, hydrogen chemisorption, and Moessbauer spectroscopy and their catalytic performance in methanol formation was also measured. At 16 at.-% iron a sharp maximum was observed in the activity which can be interpreted as being due to simultaneous promotion with iron and MgO. Independent mechanisms of promotion were found for the two modifiers: iron influenced the metallic component by forming bimetallic PdFe particles while MgO changed the properties of silica in a favourable way. 6 figs., 29 refs., 1 tab.
Channeling effect measurements have been employed to investigate radiation damage produced by 100-keV Ar ions in preferred oriented polycrystalline metal-silicide layers, such as Pd_2Si and NiSi_2 layers formed on single-crystalline Si. For room-temperature implantation, an amount of the damage in Pd_2Si layers was found to saturate at doses between 3 x 10"1"4 and 1 x 10"1"7 ions/cm"2, where the minimum aligned yield of 1.5-MeV He ions was nearly 40% of the random one. On the contrary, it was observed that the NiSi_2 layers became amorphous at doses higher than 3 x 10"1"5 ions/cm"2. These results were confirmed by the reflection electron diffraction analyses.
Cerium L_3 XANES (x-ray-absorption near-edge-structure) spectra were analyzed to separate Ce moment contributions and mixed valence (MV) in complex magnetic silicides CePd_2_-_xMn_xSi_2 (0#<=#x#<=#2). The Ce valence mixing does not vary linearly with x, but increases rapidly for x#>=#1.5. The associated moment collapse correlates with pronounced deviations of the unit-cell volume from Vegard law and the onset of structural instability. Reorientation of [001] Mn 3d antiferromagnetic order for x<2 appears to rapidly suppress the weak Ce valence mixing coexisting with antiferromagnetic order in CeMn_2Si_2.