Identifying surface reaction intermediates with photoemission tomography.

The determination of reaction pathways and the identification of reaction intermediates are key issues in chemistry. Surface reactions are particularly challenging, since many methods of analytical chemistry are inapplicable at surfaces. Recently, atomic force microscopy has been employed to identify surface reaction intermediates.

An X-ray gas monitor for free-electron lasers.

A novel X-ray gas monitor (XGM) has been developed which allows the measurement of absolute photon pulse energy and photon beam position at all existing and upcoming free-electron lasers (FELs) over a broad spectral range covering vacuum ultraviolet (VUV), extreme ultraviolet (EUV) and soft and hard X-rays. The XGM covers a wide dynamic range from spontaneous undulator radiation to FEL radiation and provides a temporal resolution of better than 200 ns. The XGM consists of two X-ray gas-monitor detectors (XGMDs) and two huge-aperture open electron multipliers (HAMPs).

The U125 insertion device beamline at the Metrology Light Source.

At the Metrology Light Source, an electron storage ring dedicated to metrological applications, the U125 insertion device beamline utilizes undulator radiation for various applications over a broad spectral range. Using a hybrid normal-incidence and grazing-incidence in-vacuum switchable plane-grating monochromator, a spectral region ranging from the near-infrared to soft X-ray is covered. The beamline is dedicated to surface-analytical methods, e.

Transverse resonance island buckets for synchrotron-radiation based electron time-of-flight spectroscopy.

At the Metrology Light Source (MLS), the compact electron storage ring of the Physikalisch-Technische Bundesanstalt (PTB) with a circumference of 48 m, a specific operation mode with two stable closed orbits for stored electrons was realized by transverse resonance island buckets. One of these orbits is closing only after three turns. In combination with single-bunch operation, the new mode was applied for electron time-of-flight spectroscopy with an interval of the synchrotron radiation pulses which is three times the revolution period at the MLS of 160 ns.

Exploring three-dimensional orbital imaging with energy-dependent photoemission tomography.

Recently, it has been shown that experimental data from angle-resolved photoemission spectroscopy on oriented molecular films can be utilized to retrieve real-space images of molecular orbitals in two dimensions. Here, we extend this orbital tomography technique by performing photoemission initial state scans as a function of photon energy on the example of the brickwall monolayer of 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA) on Ag(110). The overall dependence of the photocurrent on the photon energy can be well accounted for by assuming a plane wave for the final state.

A synchrotron-radiation-based variable angle ellipsometer for the visible to vacuum ultraviolet spectral range.

A rotating analyzer spectroscopic polarimeter and ellipsometer with a wide-range θ-2θ goniometer installed at the Insertion Device Beamline of the Metrology Light Source in Berlin is presented. With a combination of transmission- and reflection-based polarizing elements and the inherent degree of polarization of the undulator radiation, this ellipsometer is able to cover photon energies from about 2 eV up to 40 eV. Additionally, a new compensator design based on a CaF2 Fresnel rhomb is presented.

Electrophysiological evidence for the presence of receptors for cholecystokinin and bombesin on cultured astrocytes of rat central nervous system.

The action of cholecystokinin (CCK) and bombesin (Bom) was studied on the membrane potential of astrocytes in explant cultures of rat cortex, cerebellum, brain stem and spinal cord. Both peptides (10(-8) and 10(-7) M) caused a hyperpolarization of most astrocytes studied. The hyperpolarization by CCK was markedly reduced or blocked by the CCKB-antagonist L-365,260 whereas addition of the Bom-antagonist [D-Phe12,Leu14]-Bom antagonized the effects of Bom, suggesting a specific action of these peptides.

Colocalization of cholinergic, adrenergic and peptidergic receptors on astrocytes.

By means of combined immunohistochemical and auto-radiographic techniques we have studied the colocalization of cholinergic, adrenergic and peptidergic binding sites on astrocytes in explant cultures of rat spinal cord, brain stem and cerebellum. Many astrocytes which were immunostained by the monoclonal muscarinic receptor antibody M 35 were also intensely labelled by 3H-noradrenaline, the beta-adrenergic antagonist 3H-dihydroalprenolol and the peptides 125I-angiotensin II, 125I-neuropeptide Y and 3H-bradykinin. Electrophysiological studies demonstrating that muscarine, the adrenergic agonists noradrenaline and isoprenaline as well as angiotensin II, neuropeptide Y and bradykinin affect the membrane potential of the same astrocytes provide further evidence for the coexistence of cholinergic, adrenergic and peptidergic receptors on astrocytes.

Acoustical changes of loudly spoken speech and their effects on speech recognition in hearing-impaired listeners.

The level of speech is usually increased in conversations with unaided hearing-impaired listeners. However, the speaker may talk at conversational levels to aided hearing-impaired persons. In this case, the level of speech is electronically increased by the hearing aid.

Transient elevation of urinary catecholamine excretion and cholestatic liver disease in a neonate with hypopituitarism.

Hypothalamic hypopituitarism was diagnosed in a 3-month-old boy presenting with cholestatic liver disease, which resolved 5 weeks after the start of replacement therapy with hydrocortisone and human growth hormone. Clinical and pathohistological features of liver disease associated with neonatal hypopituitarism in this patient are compared to those of patients reviewed from the literature. Urinary excretion of dopa and 3-methoxytyramine but not of other catecholamine metabolites was elevated during cholestatic liver disease.

Serum vanillylmandelic acid/homovanillic acid contributes to prognosis estimation in patients with localised but not with metastatic neuroblastoma.

In 211 patients with neuroblastoma, serum vanillylmandelic acid (VMA) and homovanillic acid (HVA) levels were determined and correlated to stage, histological differentiation, ferritin, neuron-specific enolase, lactate dehydrogenase (LDH) and outcome. Elevated serum VMA and/or HVA levels were found 16% less frequently than elevated urine levels. The incidence of the elevated serum levels increased with stage (stages I-III 58%, IV 78%, IVS 100%).

Neuroblastoma screening: arguments from retrospective analysis of three German neuroblastoma trials.

The justification for a neuroblastoma screening program has been discussed controversially. The analysis of 701 patients of the German neuroblastoma trials NB 79, 82, and 85 provides additional information on this subject. The basis of our investigation was the good prognosis of stage I and II patients (92% survival 5-10 years after diagnosis) compared with 66% in stage III and 11% in metastatic disease.

Abnormal 3,4-dihydroxyphenylalanine (dopa) concentrations in plasma and urine of patients with cystic fibrosis.

Plasma and urine concentrations of the free amino acid 3,4-dihydroxyphenylalanine (dopa) were determined in a blind study in 16 children and adolescents with cystic fibrosis (CF), eight heterozygote parents of these children and in 11 healthy subjects who served as controls. To exclude any drug interference with catecholamine metabolism and to evaluate a tentative basic metabolic alteration in cystic fibrosis, the same determinations were done in 11 newly diagnosed infants (age 1-84 months). Free plasma dopa was significantly (P less than 0.

Dopamine and catecholamines in cystic fibrosis in response to a marathon race.

The excretions of 3,4-dihydroxyphenylalanine (DOPA) metabolites and 5-hydroxyindoleacetic acid (5-HIAA) were followed before, during, and after a marathon race in three patients with cystic fibrosis (CF) and three healthy controls. Moderately increased DOPA excretions in CFs compared with controls before, during, and after the race support the idea that there is an altered metabolism of DOPA in CF. Noradrenaline, adrenaline, homovanillic acid, and vanilmandelic acid were increased in CFs compared with controls mainly during and after the race, which might be a reflection of the heavier working intensity that the CF patients had in comparison with their healthy controls.

Dopamine-beta-hydroxylase in patients with cystic fibrosis.

The enzymatic activity of plasma dopamine-beta-hydroxylase (DBH) was determined in 92 children/adolescents with cystic fibrosis, in 25 parents (heterozygotes) of these patients and in 68 healthy controls. Statistically significant (P less than 0.01) lower DBH levels were found in cystic fibrosis patients (17.

Immunohistochemical localization of neurofilaments and neuron-specific enolase in 29 cases of neuroblastoma.

Twenty-nine neuroblastomas have been examined with the use of rabbit antibodies specific for each of the three neurofilament polypeptides, with a monoclonal antibody specific for the NF-L polypeptide, and with a rabbit antibody specific for neuron-specific enolase. When frozen material was used, all neuroblastomas were positive with the neurofilaments antibodies. When alcohol-fixed paraffin-embedded material was used, neurofilament staining was weaker and the fixation procedure appeared to destroy the epitopes recognized by the NF-L antibodies preferentially.

Production and characterization of monoclonal antibodies against human neuroblastoma.

MAb were derived from mice immunized with cells of the human neuroblastoma line IMR-32. Five hybridomas were selected according to their selective binding to human cell lines, tumors and normal tissues. One of them, CE7, reacted with all sympatho-adrenomedullary cells (neuroblastoma, ganglioneuroblastoma, ganglioneuroma, pheochromocytoma, adrenal medulla, sympathetic ganglion cells).

Plasma and urinary catecholamines in patients with cystic fibrosis.

In 43 patients with cystic fibrosis (age 8-23 yr, 26 boys and 17 girls) attending a summer camp in a mountain rehabilitation center and in 25 parents (heterozygotes) plasma epinephrine, norepinephrine, dopamine and plasma activity of dopamine-beta-hydroxylase were determined as well as the 24-h excretion of the free urinary amines (epinephrine, norepinephrine, dopamine), their O-methylated products (metanephrine, normetanephrine, 3-methoxytyramine) and the urinary phenolic acids (vanilmandelic and homovanillic). Also the metabolic breakdown product of serotonin in urine, the 5-hydroxyindoleacetic acid, was determined. Significantly elevated plasma dopamine (0.

Different effects of selective and nonselective beta adrenoceptor blockade on urinary catecholamine and creatinine excretion in stress.

We tested the hypothesis that (1) beta 1-selective and nonselective beta adrenoceptor blockades have a different influence on stress-induced catecholamine overshoot, and (2) beta 1-selective blockade shifts the epinephrine/norepinephrine ratio in favor of norepinephrine. Seven violinists were investigated; each performed four times in public after ingesting different beta blockers. A significantly greater urinary norepinephrine/creatinine excretion was found with selective beta blockade than with nonselective.

The role of surgery, radio- and chemotherapy in the treatment of neuroblastoma and ganglioneuroblastoma.

Personal experiences with biochemical assessments of the urinary catecholamine metabolite excretion in 460 patients with neuroblastoma and 55 patients with ganglioneuroblastoma, as well as prognostic factors and selected data characterizing the role of surgery, radio- and chemotherapy in the treatment of neuroblastoma are reviewed. Recommendations regarding optimal combinations of the 3 treatment modalities are made, taking into account age and stage.

Stage fright in musicians: a model illustrating the effect of beta blockers.

Stage fright was used to investigate the mode of action of beta blockers in acute anxiety and on the technical-motor performance of 22 performing string players. They received 100 mg of atenolol or placebo 6.5 hr before performing either in the presence or absence of an audience.

[Therapy and follow-up in pheochromocytoma].

Following a brief presentation of signs and symptoms in 13 patients with pheochromocytoma, the modern procedures for correct diagnosis and tumor localization are outlined. The importance of adequate preoperative treatment with alpha- and, if necessary, beta-adrenergic receptor blocking agents is stressed. The authors also show how the sudden life-threatening blood pressure changes which used to occur frequently during surgical manipulation of the tumor can now be reliably avoided.