DIGESTIVE ENDOSCOPY, Issue 2004
Kiyonori Kobayashi
ABSTRACT We evaluated the clinical usefulness of colonoscopic insertion of a decompression tube (decompression method) for the treatment of ileus associated with left-sided colorectal cancer. Decompression method was done in 48 patients with colorectal cancer (38 primary cancer, 10 metastatic cancer). A decompression tube was successfully inserted in all but 10 patients who had primary cancer with severe strictures. The overall insertion rate was 79%. Decompression method improved obstructive symptoms and decreased intestinal gas as evaluated on plain X-ray films of the abdomen. Emergency operation was unnecessary in 96% of the patients with primary cancers, in whom the decompression tube was successfully inserted. We conclude that decompression method can improve abdominal symptoms caused by obstructive colorectal cancer and reduce the need for emergency operation. [source]

CURRENT OPINION AMONGST RADIOLOGISTS AND UROLOGISTS IN THE UK ON PERCUTANEOUS NEPHROSTOMY AND URETERIC STENT INSERTION FOR ACUTE RENAL OBSTRUCTION: RESULTS OF A POSTAL SURVEY

BJU INTERNATIONAL, Issue 6 2007
Deen P Sharma
No abstract is available for this article. [source]

Comparison of Hospital Mortality With Intra-Aortic Balloon Counterpulsation Insertion Before vs After Primary Percutaneous Coronary Intervention for Cardiogenic Shock Complicating Acute Myocardial Infarction

CONGESTIVE HEART FAILURE, Issue 5 2010
Scott Harris DO
We hypothesized that the insertion of the IABP before primary PCI might result in better survival of patients with cardiogenic shock compared with postponing the insertion until after primary PCI. We, therefore, retrospectively studied 48 patients who had undergone primary PCI with IABP because of cardiogenic shock complicating acute myocardial infarction (26 patients received the IABP before and 22 patients after primary PCI). No significant differences were present in the baseline clinical characteristics between the 2 groups. The mean number of diseased vessels was greater in the group of patients treated with the IABP before primary PCI (2.8±0.5 vs 2.3±0.7, P=.012), but the difference in the number of treated vessels was not significant. The peak creatine kinase and creatine kinase-MB levels were lower in patients treated with the IABP before primary PCI (median, 1077; interquartile range, 438,2067 vs median, 3299; interquartile range, 695,6834; P=.047 and median, 95; interquartile range, 34,196 vs median, 192; interquartile range, 82,467; P=.048, respectively). In-hospital mortality and the overall incidence of major adverse cardiac and cerebrovascular events were significantly lower in the group of patients receiving the IABP before primary PCI (19% vs 59% and 23% vs 77%, P=.007 and P=.0004, respectively). Multivariate analysis identified renal failure (odds ratio, 15.2; 95% confidence interval, 3.13,73.66) and insertion of the IABP after PCI (odds ratio, 5.2; 95% confidence interval, 1.09,24.76) as the only independent predictors of in-hospital mortality. In conclusion, the results of the present study suggest that patients with cardiogenic shock complicating acute myocardial infarction who undergo primary PCI assisted by IABP have a more favorable in-hospital outcome and lower in-hospital mortality than patients who receive IABP after PCI. Abdel-Wahab M, Saad M, Kynast J, et al. Comparison of hospital mortality with intra-aortic balloon counterpulsation insertion before versus after primary percutaneous coronary intervention for cardiogenic shock complicating acute myocardial infarction. Am J Cardiol. 2010;105:967,971. [source]

Energy requirements of spasticity

DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 4 2001
Cheryl Hemingway MBCh B
Direct measurement of energy expended by spasticity in children with severe spastic quadriparesis is difficult. Insertion of an intrathecal baclofen pump in a 13-year-old boy with severe spasticity and profound mental retardation* resulted in an estimated 30 to 40% decrease in his spasticity. As he had been on a carefully calculated ketogenic diet and fed by gastrostomy, his precise caloric intake was known. Decrease in spasticity, on the same caloric intake, led to marked weight gain. Reduction of 100 calories intake resulted in new weight stability. It was possible therefore, to estimate indirectly energy used by his spasticity. This 100 calories, representing 34% of calories above his resting energy requirement, corresponded to an independently estimated 30 to 40% of caloric expenditure of his spasticity. It was concluded that when calculation of calories is critical, energy utilization by spasticity must be taken into consideration. [source]

Newly Developed Ultrasonic Probe With Ropeway System for Transpapillary Intraductal Ultrasonography of the Bilio,Pancreatic Ductal System

DIGESTIVE ENDOSCOPY, Issue 3 2000
Naotaka Fujita
Background: Intraductal ultrasonography of the bile/pancreatic duct using a thin-caliber ultrasonic probe (IDUS) provides excellent images of these ducts and the surrounding structures. Insertion of the device through the papilla of Vater is essential to carry out this examination. We developed a new probe with a ropeway system (XUM5RG-29R; Olympus, Tokyo) for transpapillary IDUS. Its usefulness such as ease of application and safety were prospectively evaluated. Patients and methods: During the period of October 1997 to April 1998, transpapillary IDUS using the probe was performed in 194 patients at seven medical institutions. The success rates of insertion of the probe into the bile/pancreatic duct, observation of the area of interest, and the incidence of complications were evaluated. Results: Passage of the probe through the papilla was successful without difficulty in all the patients. Successful introduction of the probe into the pancreatic duct, bile duct and both of the ducts was achieved in 98.4, 100 and 85% of the patients, respectively. Once the probe was introduced into the aimed duct, it was possible to obtain IDUS images of the area of interest in all but five patients. Mild acute pancreatitis developed in eight patients (4.1%), all of whom recovered with conservative therapy only. Conclusions: It is possible to introduce the new ultrasonic probe into the desired duct once a guide wire has been inserted. This type of ultrasonic probe is quite useful when performing transpapillary IDUS of the bile and/or pancreatic duct. [source]

Recombinant clotting factor VIII concentrates: Heterogeneity and high-purity evaluation

ELECTROPHORESIS, Issue 16 2010
Gian Maria D'Amici
Abstract Factor VIII is an important glycoprotein involved in hemostasis. Insertion of expression vectors containing either the full-length cDNA sequence of human factor VIII (FLrFVIII) or B-domain deleted (BDDrFVIII) into mammalian cell lines results in the production of recombinant factor VIII (rFVIII) for therapeutic usage. Three commercially available rFVIII concentrates (Advate®, Helixate NexGen® and Refacto®), either FLrFVIII or BDDrFVIII, were investigated by 1- and 2-DE and MS. The objective of this study was to compare the heterogeneity and the high purity of both rFVIII preparations before and after thrombin digestion. In particular, the 2-D gel was optimized to better highlight the presence of contaminants and many unexpected proteins. Recombinant strategies consisting of insertion of expression vectors containing BDDrFVIII and FLrFVIII resulted in homogeneous and heterogeneous protein products, respectively, the latter consisting in a heterogeneous mixture of various B-domain-truncated forms of the molecule. Thrombin digestion of all the three rFVIII gave similar final products, plus one unexpected fragment of A2 domain missing 11 amino acids. Regarding the contaminants, Helixate NexGen® showed the presence of impurities, such as Hsp70,kDa, haptoglobin and proapolipoprotein; Refacto® showed glutathione S -transferase and ,-lactamase, whereas Advate® apparently did not contain any contaminants. The proteomic approach will contribute to improving the quality assurance and manufacturing processes of rFVIII concentrates. In this view, the 2-DE is mandatory for revealing the presence of contaminants. [source]

Mechanisms of H2, H2C=CH2, and O=CH2 Insertion into Cp2Zr(,2 -SiMe2=NtBu)(PMe3)

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 14 2007
Siwei Bi
Abstract In this paper, the mechanisms for the insertion of H2, H2C=CH2, and O=CH2 into the Zr,Si bond of Cp2Zr(,2 -SiMe2=NtBu)(PMe3) (R) are theoretically investigated with the aid of density functional theory (DFT) calculations. The structure of the H2 insertion product P is discussed on the basis of our calculations, and its bonding features are rationalized in terms of molecular orbital theory. The regiochemistry for insertion of O=CH2 has also been theoretically investigated. It is found that the relative stabilities of the three insertion products of R are in the order P < P, < P,. For the reactions of R with H2 and CH2=CH2, the rate-determining steps are the insertions of H2 and CH2=CH2 into the Zr,Si bond of Cp2Zr(,2 -SiMe2=NtBu) (Int1), whereas PMe3 dissociation is the rate-determining step for the reaction of R with O=CH2. Only the precursor Int2,, formed by the coordination of O=CH2 to the Zr atom, is located; those formed by the coordination of H2 and CH2=CH2 to Int1 are not found.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source]

Molecular Library Obtained by Allene Insertion into the Pd,C Bond of Cyclopalladated Complexes: Biological and Pharmacological Evaluation

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 8 2004
Claude Sirlin
Abstract A minilibrary of cationic N-heterocycles has been prepared and evaluated. The potential for the preparation was a result of the high versatility of palladium-mediated chemistry. The synthesis of the novel molecules was based on intramolecular quaternization of tertiary amine attached allylpalladium complexes. The steric and electronic factors of the reaction are discussed. The structures of the synthesized molecules made them candidates for precise biological and pharmacological evaluations. Of the various N-heterocyclic compounds, 2,2-dimethyl-3-methylenenaphtho[def]quinolizinium showed antibacterial activity at micromolar concentrations. This compound also proved to be a nanomolar competitive antagonist for the channel site of the nicotinic acetylcholine receptor. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]

Role of the Peripheral Intravenous Catheter in False-positive D-dimer Testing

ACADEMIC EMERGENCY MEDICINE, Issue 2 2001
Alan C. Heffner MD
Abstract. Objective: To determine whether inserting a peripheral intravenous catheter (IV) can significantly increase the circulating D-dimer concentration. Methods: Twenty healthy young adult volunteers underwent cannulation of an antecubital vein with a 20-gauge Teflon IV. Time 0 venous blood was drawn during IV insertion. The IV was salinelocked and left in place for 90 minutes, at which time a second venipuncture was performed in a contralateral antecubital vein (+90 min). A qualitative D-dimer assay [erythrocyte-agglutination assay, SimpliRED (SRDD)] and a quantitative spectrophotometric assay [enzyme-linked immunosorbent assay (EIA), Dimertest Gold] were performed on all samples. Time 0 means (±SD) were compared with +90 min means by paired t-test, and SRDD pairs were compared with McNemar's test. Results: Time 0 initial venipuncture blood samples yielded a mean D-dimer concentration of 15 ± 24 ng/mL, with 2/20 SRDD tests read as positive (95% CI = 1% to 32%). At +90 min, the D-dimer concentration was 33 ± 21 ng/mL (p = 0.04 vs time 0), with 5/20 SRDD tests read as positive (95% CI = 9% to 49%, p = 0.248). Conclusions: Insertion of an IV increased the circulating D-dimer concentration (determined by EIA), but did not lead to a significant increase in false-positive conversion of the SRDD. An effort should be made to perform D-dimer testing on "first-stick" blood to optimize specificity. However, a strongly positive D-dimer reaction cannot be ascribed to the presence of an IV. [source]

Altering the surface properties of baculovirus Autographa californica NPV by insertional mutagenesis of the envelope protein gp64

FEBS JOURNAL, Issue 18 2002
Alexandra Spenger
The envelope protein gp64 of the baculovirus Autographa californica nuclear polyhedrosis virus is essential for viral entry into insect cells, as the glycoprotein both mediates pH-dependent membrane fusion and binds to host cell receptors. Surface modification of baculovirus particles by genetic engineering of gp64 has been demonstrated by various strategies and thus has become an important and powerful tool in molecular biology. To improve further the presentation of peptides on the surface of baculovirus particles, several insertion sites within the gp64 envelope protein were selected by their theoretical maximum surface probability and investigated for efficient peptide presentation. The ELDKWA peptide of the gp41 of HIV-1, specific for the human mAb 2F5, was inserted into 17 different positions of the glycoprotein gp64. Propagation of viruses was successful in 13 cases, mutagenesis at four positions did not result in production of intact virus particles. Western blotting, FACS analysis and ELISA were used for characterization of the different binding properties of the mutants. Insertion of this peptide into the native envelope protein resulted in high avidity display on the surface of baculovirus particles. This approach offers the possibility of effective modification of surface properties in regard to host range specificity and antigen display. [source]

Insertion of light-harvesting chlorophyll a/b protein into the thylakoid

FEBS JOURNAL, Issue 4 2000
Topographical studies
The major light-harvesting chlorophyll a/b -binding protein (Lhcb1,2) of photosystem II is inserted into the thylakoid via the signal recognition particle dependent pathway. However, the mechanism by which the protein enters the membrane is at this time unknown. In order to define some topographical restrictions for this process, we constructed several recombinant derivatives of Lhcb1 carrying hexahistidine tags at either protein terminus or in the stromal loop domain. Additionally, green fluorescent protein (GFP) was fused to either terminus. None of the modifications significantly impair the pigment-binding properties of the protein in the in vitro reconstitution of LHCII. With the exception of the C-terminal GFP fusion, all mutants stably insert into isolated thylakoids in the absence of Ni2+ ions. The addition of low concentrations of Ni2+ ions abolishes the thylakoid insertion of C-terminally His-tagged mutants whereas the other His-tagged proteins fail to insert only at higher Ni2+ concentrations. The C-terminus of Lhcb1 must cross the membrane during protein insertion whereas the other sites of Lhcb1 modification are positioned on the stromal side of LHCII. We conclude that a Ni2+ -complexed His tag and fusion to GFP inhibit translocation of the protein C-terminus across the thylakoid. Our observations indicate that the N-terminal and stromal domain of Lhcb1 need not traverse the thylakoid during protein insertion and are consistent with a loop mechanism in which only the C-terminus and the lumenal loop of Lhcb1 are translocated across the thylakoid. [source]

Syntheses, Li Insertion, and Photoactivity of Mesoporous Crystalline TiO2

ADVANCED FUNCTIONAL MATERIALS, Issue 17 2009
Wenbo Yue
Abstract Ordered mesoporous rutile and anatase TiO2 samples are prepared using mesoporous silica SBA-15 as template and freshly synthesized titanium nitrate and titanium chloride solutions as precursors. The rutile material formed from the nitrate solution is monocrystalline and contains minimal amounts of Si with a Si:Ti ratio of 0.031(4), whereas the anatase material formed from the chloride solution comprises nanocrystals and contains a higher content of Si with a Si:Ti ratio of 0.18(3). It is found that control of temperature and selection of Ti-containing precursor play important roles in determining the crystal phase and crystallinity. A possible formation mechanism of porous crystalline TiO2 is suggested. Characterization of these porous materials is performed by XRD, HRTEM, and nitrogen adsorption/desorption. SBA-15-templated mesoporous rutile TiO2 exhibits a higher Li ion insertion capability than KIT-6-templated TiO2 due to its larger surface area. Likewise mesoporous anatase TiO2:SiO2 composite has a better photoactivity than bulk TiO2 or TiO2 -loaded SBA-15 for bleaching methylene blue. [source]

Insertion of MLL sequences into chromosome band 5q31 results in an MLL-AF5Q31 fusion and is a rare but recurrent abnormality associated with infant leukemia

GENES, CHROMOSOMES AND CANCER, Issue 3 2003
Ramona Deveney
MLL gene rearrangements leading to production of MLL fusion proteins are commonly detected in infant leukemia patients; the most common MLL fusion associated with infant leukemia is the MLL-AF4 fusion. A single case of chromosomal rearrangement leading to production of an MLL fusion with AF5Q31, a gene structurally similar to AF4, has been detected recently in the malignant cells of an infant leukemia patient. We have identified a second case of MLL-AF5Q31 fusion, arising from an insertion of MLL sequences into chromosome 5, also in an infant leukemia patient. Because MLL and AF5Q31 are transcribed in opposite orientations, a simple balanced chromosomal translocation cannot produce a fusion protein, and complex chromosomal rearrangements such as insertions and inversions are required to produce an MLL-AF5Q31 fusion protein. This report demonstrates that chromosomal insertion of MLL sequences is a rare but recurrent abnormality associated with infant leukemia. © 2003 Wiley-Liss, Inc. [source]

A gene trap knockout of the abundant sperm tail protein, outer dense fiber 2, results in preimplantation lethality,

GENESIS: THE JOURNAL OF GENETICS AND DEVELOPMENT, Issue 11 2006
Nicholas A. Salmon
Abstract Outer dense fiber 2 (Odf2) is highly expressed in the testis where it encodes a major component of the outer dense fibers of the sperm flagellum. Furthermore, ODF2 protein has recently been identified as a widespread centrosomal protein. While the expression of Odf2 highlighted a potential role for this gene in male germ cell development and centrosome function, the in vivo function of Odf2 was not known. We have generated Odf2 knockout mice using an Odf2 gene trapped embryonic stem cell (ESC) line. Insertion of a gene trap vector into exon 9 resulted in a gene that encodes a severely truncated protein lacking a large portion of its predicted coil forming domains as well as both leucine zipper motifs that are required for protein,protein interactions with ODF1, another major component of the outer dense fibers. Although wild-type and heterozygous mice were recovered, no mice homozygous for the Odf2 gene trap insertion were recovered in an extended breeding program. Furthermore, no homozygous embryos were found at the blastocyst stage of embryonic development, implying a critical pre-implantation role for Odf2. We show that Odf2 is expressed widely in adults and is also expressed in the blastocyst stage of preimplantation development. These findings are in contrast with early studies reporting Odf2 expression as testis specific and suggest that embryonic Odf2 expression plays a critical role during preimplantation development in mice. genesis 44:515,522, 2006. Published 2006 Wiley-Liss, Inc. [source]

Guest-Induced Chirality in the Ferrimagnetic Nanoporous Diamond Framework Mn3(HCOO)6,

ADVANCED FUNCTIONAL MATERIALS, Issue 4 2007
B. Zhang
Abstract Chiral magnets are obtained by inclusion of chiral guest molecules into the channels of an achiral nanoporous ferrimagnet consisting of the Mn3(HCOO)6 (1) framework. Insertion of the R or the S enantiomer of 2-chloropropan-1-ol (CH3C*HClCH2OH) in the chiral pores of the previously emptied framework (space group P21/c) results in the two corresponding chiral solids (1R and 1S, space group P21), while insertion of a racemic mixture of the two enantiomers retains the achirality of the host for the meso solid (1RS, space group P21/c). The R guest is ordered in the M channels while the S guest is ordered in the P channels. In contrast, the R guests in the P channels and the S guests in the M channels are disordered on two crystallographic orientations. For the racemic mixture of the two enantiomers in 1RS, random disorder of guests in both channels is observed. Thus, the localization of the guest molecule depends on the nature of the surface to recognize the guest of a particular chirality. The guest inclusion compounds are thermally stable. The 1R and 1S compounds are optically active. All the compounds adopt a ferrimagnetic ground state. Compared to the host framework of 1 without guest, the Curie temperature decreases for both 1R and 1S but increases for 1RS. The additional interactions between the framework and the inserted guest alcohols strengthen the lattice via hydrogen bonds and other electrostatic forces, and it might account for the significant lowering of the lattice contribution as well as the magnetic component to the specific heat capacity upon guest loading. [source]

Insertion of Molecular Oxygen in Transition-Metal Hydride Bonds, Oxygen-Bond Activation, and Unimolecular Dissociation of Metal Hydroperoxide Intermediates.

HELVETICA CHIMICA ACTA, Issue 3 2008
Short Communication
Abstract Thermal activation of molecular oxygen is observed for the late-transition-metal cationic complexes [M(H)(OH)]+ with M=Fe, Co, and Ni. Most of the reactions proceed via insertion in a metalhydride bond followed by the dissociation of the resulting metal hydroperoxide intermediate(s) upon losses of O, OH, and H2O. As indicated by labeling studies, the processes for the Ni complex are very specific such that the O-atoms of the neutrals expelled originate almost exclusively from the substrate O2. In comparison to the [M(H)(OH)]+ cations, the ionmolecule reactions of the metal hydride systems [MH]+ (M=Fe, Co, Ni, Pd, and Pt) with dioxygen are rather inefficient, if they occur at all. However, for the solvated complexes [M(H)(H2O)]+ (M=Fe, Co, Ni), the reaction with O2 involving OO bond activation show higher reactivity depending on the transition metal: 60% for the Ni, 16% for the Co, and only 4% for the Fe complex relative to the [Ni(H)(OH)]+/O2 couple. [source]

Total Synthesis of Murrayanine Involving 4,5-Dimethyleneoxazolidin-2-ones and a Palladium(0)-Catalyzed Diaryl Insertion

HELVETICA CHIMICA ACTA, Issue 8 2007
Pablo Bernal
Abstract A new total synthesis of the natural carbazole murrayanine (1) was developed by using the 4,5-dimethyleneoxazolidin-2-one 12 as starting material. The latter underwent a highly regioselective Diels,Alder cycloaddition with acrylaldehyde (=prop-2-enal; 13) to give adduct 14 (Scheme,3). Conversion of this adduct into diarylamine derivative 9 was carried out via hydrolysis and methylation (Scheme,4). Differing from our previous synthesis, in which such a diarylamine derivative was transformed into 1 by a PdII -stoichiometric cyclization, this new approach comprised an improved cyclization through a more efficient Pd0 -catalyzed intramolecular diaryl coupling which was applied to 9, thus obtaining the natural carbazole 1 in a higher overall yield. [source]

Safety of supracostal punctures for percutaneous renal surgery

INTERNATIONAL JOURNAL OF UROLOGY, Issue 10 2006
RAJIV YADAV
Aim: Supracostal superior calyceal access has been shown to be the most suitable approach for staghorn calculi, calculi in the upper ureter and complex inferior calyceal calculi, as well as for antegrade endopyelotomy. However, many urologists hesitate in using this approach because of the potential for chest complications. The aim of this study was to analyze one institution's data regarding the safety and efficacy of this approach for percutaneous renal surgery. Methods: A total of 890 renal units (762 patients) were treated with percutaneous renal surgery (849 percutaneous nephrolithotomy, 41 antegrade endopyelotomy) from July 1998 to July 2004. Supracostal access was obtained in 332 (37.3%) patients. The indications for a supracostal approach were ureteropelvic junction obstruction, staghorn and complex inferior calyceal calculi, and stones in the upper calyx or the upper ureter. All punctures were made by the urologist under C-arm fluoroscopic guidance in the prone position. Results: The interspace between 11th and 12th rib was used in all except four patients in whom the puncture was made above the 11th rib. Eleven patients (3.31%) had a pleural breach presenting with fluid in the chest. Insertion of a chest tube was required in seven patients, while other four were managed conservatively. No patient had injury to the lung or other viscera. Hospital stay was not significantly prolonged as a result of the pleural breach in any patient. Except for staghorn calculi where multiple tracts were a necessity for maximal clearance, a single supracostal superior or middle posterior calyceal access served the purpose in 86% (177/205) of patients who underwent percutaneous surgery for renal or upper ureteric calculi. Conclusions: The supracostal superior calyceal approach was found to be effective as well as safe, with an acceptably low risk of chest complications. [source]

A Density Functional Study of Ethylene Insertion into the M-methyl (M = Ti, Zr) Bond for Different Catalysts, with a QM/MM Model for the Counterion, B(C6F5)3CH3,

ISRAEL JOURNAL OF CHEMISTRY, Issue 4 2002
Kumar Vanka
Single site homogeneous catalysts have been studied extensively in recent years as alternatives to traditional heterogeneous catalysts. The current theoretical study uses density functional theory to study the insertion process of the ethylene monomer into the titanium-carbon chain for contact ion-pair systems of the type [L1L2TiCH3 -,-CH3 -B(C6F5)3], where L1, L2, are Cp, NPH3, and other ligands. Different modes of approach cis and trans to the ,-CH3 bridge were considered. The counterion, B(C6F5)3CH3,, was modeled by QM/MM methods. The value of ,Htot,the total barrier to insertion,was found to be positive (in the range of 4,15 kcal/mol). The ability of the ancillary ligands, L1 and L2, to stabilize the ion-pair was found to be an important factor in determining the value of ,Htot. On replacing the titanium metal center with zirconium, the ,Htot values were found to be lowered (in the range of 2,9 kcal/mol), indicating that they would be better catalysts than their titanium analogues. The size of the ligands L1 and L2 was increased by replacing hydrogens in the ligands with tertiary butyl groups. The value of ,Htot was found to increase (in the range of 10,28 kcal/mol) in contrast to the simple systems, for both the cis and trans cases of approach, with the cis mode of approach giving lower values of ,Htot. Solvent effects were incorporated with cyclohexane (, = 2.023) as the solvent, and were found to have a minor influence, ±(0.5,1.5) kcal/mol) on the insertion barrier for all the cases studied. [source]

Thermally stimulated depolarization study in polyvinylidenefluoride,polysulfone polyblend films

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010
Pooja Saxena
Abstract Thermally stimulated depolarization currents (TSDCs) in short- and open-circuit modes in polyvinylidenefluoride (PVDF),polysulfone (PSF) polyblend have been recorded. The TSDC thermograms of PVDF and PSF in short-circuit mode show two peaks, whereas the polyblend of the two polymers shows a single peak. With the increase in PSF weight percentage in the polyblend, the magnitude of TSDC peak current increased and the peak current position shifted toward the lower temperature side. The single peak in polyblend appears at 165°C ± 10°C, which is at higher temperature than the temperature of low-temperature peak for individual polymers. This suggests that this peak may be due to dipolar polarization. Subsequently, shifting of peak toward higher temperature side with increase in polarizing temperature indicates the space charge peak. This contradiction has been explained on the basis of induced dipole theory. The behavior of short circuit TSDC could be explained in terms of the heterocharge caused by dipole orientation and ionic homocharge drift, together with the injection of charge carriers from electrodes and their subsequent localization in surface and bulk traps. However, two oppositely directed TSDC peaks observed in open-circuit mode in all the polyblend samples could be considered as the result of superposition of two overlapped and oppositely directed peaks, one caused by relaxation of dipole polarization and the other by the space charge. Thus, we have compared TSDC measured in open- and short-circuit modes to distinguish between these two relaxation processes and separate them. There is only one broad peak observed in the short-circuit mode of the polyblend, which entirely corresponds to the relaxation of dipole polarization. Insertion of a dielectric gap in the open-circuit mode does not affect the dipole current, but the space charge component flowing in the opposite direction is added to the former. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]

Hypoxemia Complicating LVAD Insertion: Novel Application of the Amplatzer PFO Occlusion Device

JOURNAL OF CARDIAC SURGERY, Issue 2 2007
Coimbatore V. Srinivas M.D., F.R.C.A.
The patient was successfully managed with percutaneous closure of the interatrial defect using an Amplatzer PFO occlusion device and judicious reduction in LVAD flows. [source]

Facilitated Insertion of the Hancock II Bioprosthesis

JOURNAL OF CARDIAC SURGERY, Issue 3 2002
Ph.D., Vivek Rao M.D.
No abstract is available for this article. [source]

Reconstitution of Photosystem II Reaction Center with Cu-Chlorophyll a

JOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 11 2006
Shuang Liu
Abstract An isolated photosystem (PS) II reaction center (RC) with altered pigment content was obtained by chemical exchange of native chlorophyll a (Chl) with externally added Cu-Chl a (Cu-Chl). Pigment composition and spectroscopic properties of the RC exchanged with Cu-Chl were compared with native RC and RC treated with Chl in the same way. High-performance liquid chromatography analysis showed approximately 0.5 Cu-Chl per two pheophytin in the Cu-Chl-reconstituted RC preparation. Insertion of Cu-Chl resulted in a decrease in absorption at 670 nm and an increase at 660 nm, suggesting that the peripheral Chl may have been displaced. Fluorescence emission spectra of the Cu-Chl-reconstituted RC displayed a marked decrease in fluorescence yield and a blue shift of the band maximum, accompanied by the appearance of a broad peak at a shorter wavelength, indicating that energy transfer in the modified RC was disturbed by Cu-Chl, a quencher of the excited state. However, there were few differences in the circular dichroism (CD) spectra, suggesting that the arrangement of pigments and proteins responsible for the CD signal was not significantly affected. In addition, no obvious change in peptide components was found after the exchange procedure. (Managing editor: Ping He) [source]

Increased Susceptibility of Rice Following Insertion of Amylopullulanase Gene, to Brown Spot Caused by Bipolaris oryzae

JOURNAL OF PHYTOPATHOLOGY, Issue 9 2008
M.-Y. Ting
Abstract Transgenic rice expressing an amylopullulanase (APU) from the bacterium Thermoanaerobacter ethanolicus 39E produces grains which are less expensive to process for production of sugar syrup and protein-enriched flour. During risk assessment of the transgenic line in a field test, brown spot disease caused by Bipolaris oryzae was found more severe on the transgenic line APU than on its parental line TNG67. When lines APU and TNG67 were inoculated at seedling, tillering or heading stage with B. oryzae isolated from line TNG67, the disease was more severe on line APU than on line TNG67 at heading stage, but not at the seedling or tillering stage. However, when B. oryzae isolated from line APU was used in the inoculation tests, the disease was more severe on line APU than on line TNG67 at seedling stage, but not at the tillering or heading stage. To our knowledge, this is the first report of an unintended change in a transgenic plant to become more susceptible to a disease than the non-transgenic plant. [source]

Is ECG-guidance a helpful method to correctly position a central venous catheter during prehospital emergency care?

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2005
J. S. David
Background:, Insertion of a central venous catheter (CVC) in an emergency situation is challenging and may be potentially associated with more complications. Because CVC positioning by ECG-guidance may help to decrease the frequency of a malpositioned catheter, we decided to prospectively evaluate the usefulness of positioning a CVC by ECG-guidance during prehospital emergency care. Methods:, Prospective observational study during which all patients requiring CVC placement during prehospital care were included. We compared two periods of 1 year during which CVCs were inserted without and then with the help of ECG-guidance. Results:, Eighty successive patients were included. We observed a significant reduction of incorrectly positioned CVCs with ECG-guidance (13% vs. 38%, P < 0.05) and a decreased number of chest X-rays needed to verify the position of the CVC (40 vs. 54, P < 0.05). Conclusion:, ECG-guidance is a safe and feasible technique which significantly improved the rate of CVCs correctly positioned during prehospital emergency care. [source]

Phased-Array Intracardiac Echocardiography for Guiding Transseptal Catheter Placement: Utility and Learning Curve

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 4 2002
SUSAN B. JOHNSON
JOHNSON, S.B., et al.: Phased-Array Intracardiac Echocardiography for Guiding Transseptal Catheter Placement: Utility and Learning Curve. The utility of a new intracardiac 64-element, phased-array, longitudinal ultrasound imaging system for guiding transseptal catheterization was assessed during 69 crossing attempts in 45 dogs because of the inherent limitations of fluoroscopy and mechanical ultrasound. Multifrequency (7.5,8.5 MHZ) imaging of the membranous fossa ovalis, posterior left atrium, and left atrial appendage was conducted from the right atrium. Contact of the Brockenbrough needle with the interatrial septum as reflected by membranous fossa ovalis "tenting" was uniformly identified. Transseptal crossing and advancement of the dilator and sheath were adequately imaged because of deeper ultrasound tissue penetration. Transseptal catheterization was successfully accomplished in 44 of 45 dogs: on the first attempt in 40 and with additional attempts in 4 and confirmed by direct far-field imaging of nonagitated saline injection via the sheath. Total transseptal catheterization time was 3.0 ± 1.8 minutes. Unsuccessful first attempts and/or subsequent sheath pullback into the right atrium with catheter manipulation were also readily recognized. Insertion of the transseptal needle beyond the ultrasound imaging plane resulted in perforation of the posterior left atrial wall in three attempts. Accompanying effusions in these animals and three others related to subsequent intracardiac ablation catheter manipulation were readily identified and monitored echocardiographically. In conclusion, phased-array intracardiac imaging provides a highly reliable means of guiding transseptal access to the left atrium. In addition, inadvertent complications such as perforation and pericardial effusion development can be readily recognized. [source]

Insertion characteristics, sealing pressure and fiberoptic positioning of CobraPLA in children

PEDIATRIC ANESTHESIA, Issue 10 2007
MAURIZIO PASSARIELLO MD
Summary Background:, The CobraPLATM is a new supraglottic airway device designed for the use in spontaneously breathing and mechanically ventilated patients. In adults it has been found as effective as the LMA, but with better sealing qualities. The aim of the present study was to evaluate fit and sealing characteristics of CobraPLA size 1.5 and 2 in mechanically ventilated children. Methods:, Forty children, ASA I/II, aged 1,10 years, weighing 10,35 kg were scheduled for minor surgical procedures. The number of attempts for insertion and fiberoptic positioning of the CobraPLA was assessed. After muscle relaxation had been achieved, airway sealing pressure was measured by gradually increasing maximum inspiratory pressure to a maximum of 30 cmH2O. Results:, Insertion of CobraPLA was successful at the first attempt in 90% of patients. The vocal cords were visualized in 90% of patients (grade 0: 2.5%, grade 1: 7.5%, grade 2: 30%, grade 3: 15%, grade 4: 45%). Median sealing pressure was 20.0 ± 6.0 cmH2O. In 21% of patients gastric insufflation was observed at a peak inspiratory pressure of 20 cmH2O or below. Conclusions:, The CobraPLA was found to have easy insertion characteristics and good anatomical fitting in children between 10 and 35 kg. If positive pressure ventilation with CobraPLA size 1.5 and 2.0 is required, peak inspiratory pressure should be kept below the leak pressure and the abdomen closely monitored for signs of gastric insufflation. [source]

The ProSealTM laryngeal mask airway in children

PEDIATRIC ANESTHESIA, Issue 3 2005
M. LOPEZ-GIL MD
Summary Background :,The ProSealTM (PLMA) is a new laryngeal mask device with a modified cuff to improve the seal and a drain tube to provide access to the gastrointestinal tract. We assessed the performance of the size 2 (which has no dorsal cuff) and size 3 (which has a dorsal cuff) in terms of insertion success, efficacy of seal, tidal volume, gas exchange, fiberoptic position, gastric tube placement and frequency of problems. Methods :,Eighty children undergoing minor surgery were studied (n = 40, size 2 PLMA, weight 10,25 kg; n = 40, size 3 PLMA, weight >25,50 kg). Induction was with remifentanil and propofol. Insertion was with the introducer tool and by experienced users. Maintenance was with propofol or sevoflurane and pressure controlled ventilation. Results :,The first-time and overall insertion success rate was 84 and 100%, respectively. Oropharyngeal leak pressure was 31 ± 5 cmH2O. There were no gastric or drain tube air leaks. Tidal volume and gas exchange was adequate in all patients, other than two brief episodes of hypoxia because of airway reflex activation. The vocal cords and epiglottis were visible in 99 and 80%, respectively, via the airway tube. The first-time and overall insertion success rate for gastric tube insertion was 87 and 100%, respectively. During maintenance, the PLMA was removed in one patient with airway reflex activation and another required epinephrine for bronchospasm. There were no differences in performance between the sizes 2 and 3 PLMA. Conclusion :,The PLMA is an effective airway device in children and isolates the glottis from the esophagus when correctly positioned. Despite the lack of a dorsal cuff, the performance of the size 2 was similar to the size 3 PLMA in the age groups tested. [source]

GaN layer growth by HVPE on m-plane sapphire substrates

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue S2 2009
Alexander Usikov
Abstract Semipolar GaN layers were grown on m-plane sapphire substrates by HVPE. Insertion of AlxGa1,xN (x , 0.1-0.6) layer in-between m-plane sapphire substrate and GaN layer promoted to improve crystalline quality and to grow of semipolar (11-22) plane GaN layers. X-ray diffraction (11-22) ,-scan rocking curve FWHM of 298 arcsec was measured for a 30 ,m thick (11-22) GaN layer. Depending on growth conditions, m-plane GaN layer having micro-crystallites of other orientations (mainly of (11-24) plane GaN layer) was also grown. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

The role of setback layers on the breakdown characteristics of AlGaAs/GaAs/GaN HBTs

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2008
Chuanxin Lian
Abstract Breakdown voltages (VCBO) of AlGaAs/GaAs/GaAs and AlGaAs/GaAs/GaAs-setback/GaN HBTs have been compared both theoretically and experimentally with respect to setback layer thicknesses and the doping type. VCBO was calculated using a non-local energy model. The hard breakdown voltage was measured on as-grown GaAs homojunctions and AlGaAs/GaAs/GaN HBTs formed by direct wafer fusion. The calculation showed an increase of VCBO from , 20 V to , 325 V by replacing the GaAs collector with GaN, and VCBO ,90 V was indeed measured. The smaller than predicted VCBO is attributed to the large leakage current currently present in the fused junctions. Insertion of a lightly doped GaAs setback layer has resulted in improved current gain of the fused HBTs, but it also degrades the breakdown characteristics. 20-30 nm setback layers were found to maintain VCBO significantly higher than that of GaAs homojunctions and likely reasonable current gains. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]