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1.
Phys Rev Lett ; 121(13): 136401, 2018 Sep 28.
Article in English | MEDLINE | ID: mdl-30312078

ABSTRACT

Using soft x-ray angle-resolved photoemission spectroscopy we probed the bulk electronic structure of T_{d}-MoTe_{2}. We found that on-site Coulomb interaction leads to a Lifshitz transition, which is essential for a precise description of the electronic structure. A hybrid Weyl semimetal state with a pair of energy bands touching at both type-I and type-II Weyl nodes is indicated by comparing the experimental data with theoretical calculations. Unveiling the importance of Coulomb interaction opens up a new route to comprehend the unique properties of MoTe_{2}, and is significant for understanding the interplay between correlation effects, strong spin-orbit coupling and superconductivity in this van der Waals material.

3.
Phys Rev Lett ; 118(17): 176404, 2017 Apr 28.
Article in English | MEDLINE | ID: mdl-28498707

ABSTRACT

We measured, by angle-resolved photoemission spectroscopy, the electronic structure of LiCu_{2}O_{2}, a mixed-valence cuprate where planes of Cu(I) (3d^{10}) ions are sandwiched between layers containing one-dimensional edge-sharing Cu(II) (3d^{9}) chains. We find that the Cu(I)- and Cu(II)-derived electronic states form separate electronic subsystems, in spite of being coupled by bridging O ions. The valence band, of the Cu(I) character, disperses within the charge-transfer gap of the strongly correlated Cu(II) states, displaying an unprecedented 250% broadening of the bandwidth with respect to the predictions of density functional theory. Our observation is at odds with the widely accepted tenet of many-body theory that correlation effects generally yield narrower bands and larger electron masses and suggests that present-day electronic structure techniques provide an intrinsically inappropriate description of ligand-to-d hybridizations in late transition metal oxides.

4.
Phys Rev Lett ; 115(9): 096404, 2015 Aug 28.
Article in English | MEDLINE | ID: mdl-26371668

ABSTRACT

We investigate the polaronic ground state of anatase TiO2 by bulk-sensitive resonant inelastic x-ray spectroscopy (RIXS) at the Ti L3 edge. We find that the formation of the polaron cloud involves a single 95 meV phonon along the c axis, in addition to the 108 meV ab-plane mode previously identified by photoemission. The coupling strength to both modes is the same within error bars, and it is unaffected by the carrier density. These data establish RIXS as a directional bulk-sensitive probe of electron-phonon coupling in solids.

5.
Lab Anim ; 47(1): 2-11, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23467487

ABSTRACT

The primary aim of this report is to assist scientists in selecting more reliable/suitable identification (ID) methods for their studies. This is especially true for genetically altered (GA) animals where individual identification is strictly necessary to link samples, research design and genotype. The aim of this Federation of European Laboratory Animal Science Associations working group was to provide an update of the methods used to identify rodents in different situations and to assess their implications for animal welfare. ID procedures are an indispensable prerequisite for conducting good science but the degree of invasiveness differs between the different methods; therefore, one needs to make a good ethical evaluation of the method chosen. Based on the scientific literature the advantages and disadvantages of various methods have been presented comprehensively and this report is intended as a practical guide for researchers. New upcoming methods have been included next to the traditional techniques. Ideally, an ID method should provide reliable identification, be technically easy to apply and not inflict adverse effects on animals while taking into account the type of research. There is no gold standard method because each situation is unique; however, more studies are needed to better evaluate ID systems and the desirable introduction of new and modern approaches will need to be assessed by detailed scientific evaluation.


Subject(s)
Animal Identification Systems/methods , Animal Welfare , Laboratory Animal Science/trends , Animal Identification Systems/ethics , Animal Identification Systems/instrumentation , Animals , Laboratory Animal Science/ethics , Mice , Rats , Research Design
6.
Article in English | MEDLINE | ID: mdl-15606866

ABSTRACT

Subsequent to rabies vaccination campaigns, two well-established methods for the determination of the proportion of vaccinated foxes--the detection of tetracycline (TC) in bones and the detection of virus neutralizing antibodies (VNA) in thoracic fluids--were used and compared. Special emphasis was given to the effect of a new method of bait distribution at the den, which is primarily targeted at young foxes. The overall proportion of vaccinated animals estimated by TC was 60% as compared to 50% by VNA. In young foxes overall, significantly lower proportions of vaccinated animals (58% by TC and 40% by VNA) than in adult foxes (75 and 59%) were estimated with both methods. Low proportions of vaccinated young animals were found after spring (39 and 18%), but also after autumn vaccination (56 and 35%). In contrast, after den vaccination the level of vaccination of young foxes reached that of adult foxes. The theoretical implication of the successful elimination of fox rabies in Switzerland in spite of a relatively low overall proportion of VNA-positive animals is discussed.


Subject(s)
Foxes , Rabies Vaccines/administration & dosage , Rabies virus/immunology , Rabies/epidemiology , Rabies/prevention & control , Vaccination/veterinary , Administration, Oral , Animals , Antibodies, Viral/biosynthesis , Disease Outbreaks/prevention & control , Disease Outbreaks/veterinary , Switzerland/epidemiology
7.
J Am Chem Soc ; 123(42): 10290-8, 2001 Oct 24.
Article in English | MEDLINE | ID: mdl-11603979

ABSTRACT

The first variable-temperature and variable-pressure stopped-flow spectrophotometric study of the sequential threading of alpha-cyclodextrin (alpha-CD) onto the guest dye Mordant Orange 10, S, is reported. Complementary (1)H one-dimensional (1D) variable-temperature kinetic studies and two-dimensional (2D) rotating-frame nuclear Overhauser effect spectroscopy (ROESY) and EXSY NMR studies are also reported. In aqueous solution at 298.2 K, the first alpha-CD threads onto S to form a 1:1 complex S.alpha-CD with a forward rate constant k(1,f) = 15 200 +/- 200 M(-1) s(-1) and dethreads with a reverse rate constant k(1,r) = 4.4 +/- 0.3 s(-1). Subsequently, S.alpha-CD isomerizes to S.alpha-CD (k(3,f) = 0.158 +/- 0.006 s(-1), k(3,f) = 0.148 +/- 0.006 s(-1)). This process can be viewed as a thermodynamically controlled molecular shuttle. A second alpha-CD threads onto S.alpha-CD to form a 1:2 complex, S.(alpha-CD)(2), with k(2,f) = 98 +/- 2 M(-1) s(-1) and k(2,r) = 0.032 +/- 0.002 s(-1). A second alpha-CD also threads onto S.alpha-CD to form another 1:2 complex, S.(alpha-CD)(2), characterized by k(4,f) = 9640 +/- 1800 M(-1) s(-1) and k(4,r) = 61 +/- 6 s(-1). Direct interconvertion between S.(alpha-CD)(2) and S.(alpha-CD)(2) was not detected; instead, they interconvert by dethreading the second alpha-CD and through the isomerization equilibrium between S.alpha-CD and S.alpha-CD. The reaction volumes, DeltaV(0), were found to be negative for the first three equilibria and positive for the fourth equilibrium. For the first three forward and reverse reactions, the volumes of activation are substantially more negative, indicating a compression of the transition state in comparison with the ground states. These data were used in conjunction with DeltaH, DeltaH degrees, DeltaS, and DeltaS degrees data to deduce the dominant mechanistic threading processes, which appear to be largely controlled by changes in hydration and van der Waals interactions, and possibly by conformational changes in both S and alpha-CD. The structure of the four complexes were deduced from (1)H 2D ROESY NMR studies.


Subject(s)
Azo Compounds/chemistry , Benzene Derivatives/chemistry , Coloring Agents/chemistry , Cyclodextrins/chemistry , alpha-Cyclodextrins , Kinetics , Magnetic Resonance Spectroscopy , Spectrophotometry/methods , Thermodynamics
8.
J Biol Chem ; 276(38): 35818-25, 2001 Sep 21.
Article in English | MEDLINE | ID: mdl-11463791

ABSTRACT

To gain insight into the molecular mechanisms underlying cutaneous wound repair, we performed a large scale screen to identify novel injury-regulated genes. Here we show a strong up-regulation of the RNA and protein levels of the two Ca(2+)-binding proteins S100A8 and S100A9 in the hyperthickened epidermis of acute murine and human wounds and of human ulcers. Furthermore, both genes were expressed by inflammatory cells in the wound. The increased expression of S100A8 and S100A9 in wound keratinocytes is most likely related to the activated state of the keratinocytes and not secondary to the inflammation of the skin, since we also found up-regulation of S100A8 and S100A9 in the epidermis of activin-overexpressing mice, which develop a hyperproliferative and abnormally differentiated epidermis in the absence of inflammation. Furthermore, S100A8 and S100A9 expression was found to be associated with partially differentiated keratinocytes in vitro. Using confocal microscopy, both proteins were shown to be at least partially associated with the keratin cytoskeleton. In addition, cultured keratinocytes efficiently secreted the S100A8/A9 dimer. These results together with previously published data suggest that S100A8 and S100A9 are novel players in wound repair, where they might be involved in the reorganization of the keratin cytoskeleton in the wounded epidermis, in the chemoattraction of inflammatory cells, and/or in the defense against microorganisms.


Subject(s)
Antigens, Differentiation/genetics , Calcium-Binding Proteins/genetics , Gene Expression Regulation , S100 Proteins/genetics , Wounds and Injuries/genetics , Activins , Animals , Base Sequence , Calgranulin A , Calgranulin B , DNA Primers , Humans , Inhibins/genetics , Inhibins/physiology , Mice , Mice, Inbred BALB C , Mice, Transgenic
9.
FASEB J ; 14(15): 2373-6, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11024009

ABSTRACT

Endostatin is a cleavage product of collagen XVIII that strongly inhibits tumor angiogenesis. To determine if endostatin affects other angiogenic processes, we generated full-thickness excisional wounds on the back of mice that were systemically treated with recombinant murine endostatin. No macroscopic abnormalities of the wound healing process were observed. Histological analysis revealed normal wound contraction and re-epithelialization, but a slight reduction in granulation tissue formation and reduced matrix deposition at the wound edge. The blood vessel density in the wounds of endostatin-treated mice was not affected. However, ultrastructural analysis demonstrated severe abnormalities in blood vessel maturation. The wound vessels in the endostatin-treated mice were narrowed or closed with an irregular luminal surface, resulting in a severe reduction in the number of functional vessels and extravasation of erythrocytes. Endostatin treatment did not affect the expression level and localization of collagen XVIII mRNA and protein. Furthermore, the angiogenesis regulators vascular endothelial growth factor, angiopoietin-1, and angiopoietin-2 were normally expressed in the wounds of endostatin-treated mice. However, expression of the major wound matrix proteins fibronectin and collagens I and III was significantly reduced. This reduction is likely to explain the reduced density of the wound matrix. Our results demonstrate that endostatin treatment reduces the number of functional blood vessels and the matrix density in the granulation tissue, but does not significantly affect the overall wound healing process.


Subject(s)
Angiogenesis Inhibitors/pharmacology , Collagen/pharmacology , Neovascularization, Physiologic/drug effects , Peptide Fragments/pharmacology , Wound Healing/drug effects , Angiopoietin-1 , Angiopoietin-2 , Animals , Collagen/biosynthesis , Collagen/isolation & purification , Collagen Type XVIII , Endostatins , Endothelial Growth Factors/biosynthesis , Extracellular Matrix Proteins/biosynthesis , Lymphokines/biosynthesis , Membrane Glycoproteins/biosynthesis , Mice , Protein Biosynthesis , Vascular Endothelial Growth Factor A , Vascular Endothelial Growth Factors
11.
Chem Res Toxicol ; 10(11): 1285-92, 1997 Nov.
Article in English | MEDLINE | ID: mdl-9403183

ABSTRACT

Flash photolysis of alkaline peroxynitrite solutions results in the formation of nitrogen monoxide and superoxide. From the rate of recombination it is concluded that the rate constant of the reaction of nitrogen monoxide with superoxide is (1.9 +/- 0.2) x 10(10) M-1 s-1. The pKa of hydrogen oxoperoxonitrate is dependent on the medium. With the stopped-flow technique a value of 6.5 is found at millimolar phosphate concentrations, while at 0.5 M phosphate the value is 7.5. The kinetics of decay do not follow first-order kinetics when the pH is larger than the pKa, combined with a total peroxynitrite and peroxynitrous acid concentration that exceeds 0.1 mM. An adduct between ONOO- and ONOOH is formed with a stability constant of (1.0 +/- 0.1) x 10(4) M. The kinetics of the decay of hydrogen oxoperoxonitrate are not very pressure-dependent: from stopped-flow experiments up to 152 MPa, an activation volume of 1.7 +/- 1.0 cm3 mol-1 was calculated. This small value is not compatible with homolysis of the O-O bond to yield free nitrogen dioxide and the hydroxyl radical. Pulse radiolysis of alkaline peroxynitrite solutions indicates that the hydroxyl radical reacts with ONOO- to form [(HO)ONOO].- with a rate constant of 5.8 x 10(9) M-1 s-1. This radical absorbs with a maximum at 420 nm (epsilon = 1.8 x 10(3) M-1 cm-1) and decays by second-order kinetics, k = 3.4 x 10(6) M-1 s-1. Improvements to the biomimetic synthesis of peroxynitrite with solid potassium superoxide and gaseous nitrogen monoxide result in higher peroxynitrite to nitrite yields than in most other syntheses.


Subject(s)
Nitrates/chemistry , Oxidants/chemistry , Buffers , Hydrogen-Ion Concentration , Hydroxyl Radical , Kinetics , Nitrates/chemical synthesis , Oxidants/chemical synthesis , Oxidation-Reduction , Photolysis , Pulse Radiolysis
13.
Anal Chem ; 68(17): 3045-9, 1996 Sep 01.
Article in English | MEDLINE | ID: mdl-21619372

ABSTRACT

The development of a stopped-flow instrument that operates over a temperature range of -40 to +100 °C and up to 200 MPa is described. The system has been designed so that measurements can be performed in absorbance and fluorescence modes simultaneously, without dismantling the unit. It can easily be combined with an optical system of a conventional ambient pressure setup by using light guides. Optimum optical performance and a wide operating wavelength range (220-850 nm) are achieved as the light is not passing through the pressurizing fluid. A special design for the pistons has been developed; thus, the apparatus has proven to be leak-free, even under extreme conditions (high pressure, low temperature, various solvents). The dead time of the system is found to be less than 2 ms at 298 K and is pressure independent up to 200 MPa. We examined the kinetics for the formation of the Mg(2+)-8-hydroxyquinoline chelate in aqueous solutions at pH 8.0 in order to develop a convenient alternative test method for high-pressure stopped-flow spectrometers with absorption and fluorescence detection.

15.
Ann Chir ; 46(3): 262-4, 1992.
Article in French | MEDLINE | ID: mdl-1605560

ABSTRACT

Two cases of disinsertion of the papilla following closed trauma to the abdomen were treated by suction of the papilla by a Y loop associated with temporary pyloric exclusion, gastroenterostomy and a feeding jejunostomy. The postoperative course was uneventful in the two patients. This technique is therefore indicated for associated pancreatic lesions which do not require cephalic duodenopancreatectomy.


Subject(s)
Ampulla of Vater/surgery , Duodenal Diseases/therapy , Duodenum/injuries , Abdominal Injuries/complications , Adolescent , Adult , Ampulla of Vater/physiopathology , Anastomosis, Roux-en-Y , Common Bile Duct Diseases/etiology , Common Bile Duct Diseases/surgery , Common Bile Duct Diseases/therapy , Duodenal Diseases/etiology , Duodenal Diseases/surgery , Duodenum/surgery , Enteral Nutrition , Humans , Jejunostomy , Jejunum/surgery , Male , Wounds, Nonpenetrating
18.
Bull Cancer ; 78(2): 169-72, 1991.
Article in French | MEDLINE | ID: mdl-2036487

ABSTRACT

A case of an isolated gallbladder metastasis from a malignant melanoma is reported in a 32 year old woman. The patient has been treated by cholecystectomy and chemotherapy and was free of any recurrence 5 years after treatment.


Subject(s)
Gallbladder Neoplasms/secondary , Melanoma/secondary , Skin Neoplasms/pathology , Adult , Combined Modality Therapy , Female , Follow-Up Studies , Gallbladder Neoplasms/pathology , Gallbladder Neoplasms/therapy , Humans , Melanoma/pathology , Melanoma/therapy
19.
J Chir (Paris) ; 128(1): 30-3, 1991 Jan.
Article in French | MEDLINE | ID: mdl-2016366

ABSTRACT

Injuries to the duodenum are rare and their treatment is controversial. We have wanted to assess the results of treatment in 9 cases of duodenal trauma operated successively. 6 patients were operated at once because of associated lesions producing a state of shock. The other 3 had isolate lesions and were all operated after a waiting time. 5 patients had a simple suture after excision of the margins of the wound. 2 underwent controlled fistulization on a Pezzer probe associated to a feeding jejunostomy. In 2 cases, papillar disinsertion was treated by cupping the papilla with an ascended loop and by temporary pyloric exclusion. No patient died after surgery, and no duodenal fistula was noted. In case of controlled fistulization, the scar was obtained within 21 days. We think that duodenal wounds examined early can readily be sutured if there is no loss of substance. When the duodenal wound is isolate, the delay in treatment leads us to prefer controlled fistulization associated to feeding jejunostomy.


Subject(s)
Duodenal Diseases/surgery , Duodenum/injuries , Adolescent , Adult , Aged , Duodenal Diseases/diagnostic imaging , Female , Humans , Male , Middle Aged , Postoperative Complications , Rupture , Tomography, X-Ray Computed
20.
Chirurgie ; 117(4): 258-61; discussion 261-2, 1991.
Article in French | MEDLINE | ID: mdl-1817819

ABSTRACT

In the present study, we try to discuss the results of the "en bloc" surgical resection of the extensive cancer of the colon which infiltrates one or more of the neighboring organs. Data from 41 patients who underwent this kind of operation from 1970 to 1988 were reviewed. The localisation, currently seen of this cancer, was the sigmoid colon and the number of the infiltrated neighboring organs varied from 1 to 3. The small intestine and the urinary tract were the most frequently infiltrated organs. The classification of Dukes was used: 14 cases were on stage B and 27 on stage C. The operative mortality was 9.7% and the morbidity was 38%. The survival rate at 5 years was calculated with the Kaplan-Meier method. It was 48% with a significant difference between stage B (91%) and stage C (25%). These results were similar to those of the authors found in the literature in the past ten years. They justify these extended resections.


Subject(s)
Colectomy/methods , Colonic Neoplasms/surgery , Adult , Aged , Aged, 80 and over , Colectomy/adverse effects , Colectomy/mortality , Colonic Neoplasms/pathology , Female , Follow-Up Studies , Humans , Lymphatic Metastasis , Male , Middle Aged , Neoplasm Invasiveness , Neoplasm Staging , Prognosis , Retrospective Studies , Survival Rate
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