Superlocalization of Excitons in Carbon Nanotubes at Cryogenic Temperature.

At cryogenic temperature and at the single emitter level, the optical properties of single-wall carbon nanotubes depart drastically from that of a one-dimensional (1D) object. In fact, the (usually unintentional) localization of excitons in local potential wells leads to nearly 0D behaviors such as photon antibunching, spectral diffusion, inhomogeneous broadening, etc. Here, we present a hyperspectral imaging of this spontaneous exciton localization effect at the single nanotube level using a super-resolved optical microscopy approach. We report on the statistical distribution of the trap localization, depth, and width. We use a quasi-resonant photoluminescence excitation approach to probe the confined quantum states. Numerical simulations of the quantum states and exciton diffusion show that the excitonic states are deeply modified by the interface disorder inducing a remarkable discretization of the excitonic absorption spectrum and a quenching of the free 1D exciton absorption.

[Effect of optimized integrated management on long-term effectiveness of cardiologic rehabilitation]. / Einfluss eines optimierten Schnittstellenmanagements auf die Langzeiteffektivität der kardiologischen Rehabilitation.

BACKGROUND AND OBJECTIVE: Long-term risk factor (RF) modification after cardiac rehabilitation (CR) is less than satisfactory. Problems of communication between the CR centre and the practising physician (GP) are one potential source of sub-optimal management. The goal of the PROTECT-study was to evaluate the influence of improved communication between rehabilitation centres and the GP on the quality of RF-modification. PATIENTS AND METHODS: In 50 specialized CR centres 882 patients in the group with intensified communication were compared to 160 patients in the usual care group. All patients underwent a course of residential CR. Intensified communication was attempted by a total of four phone calls to the GP, a RF booklet in which the RF profile, the individual RF treatment goals and the current RF status were delineated. Main treatment goals with respect to RF-modification after 6 months were: Blood pressure < 140/90 mmHg, LDL-Cholesterol < 100 mg/dl or at least 115 mg/dl and a body mass index of < 25 or at least < 30. RESULTS: The percentage of of patients with adequate blood pressure control (< 140/90 mmHg) was 85.1% vs. 85%, with LDL-cholesterol < 100 mg/dl 27.2% vs. 23.9%, with good body-mass index (< 25) 32.4% vs. 28.2% (intensified communication vs. control group; p = ns). The treatment initiated by the CR centres was continued in about 90% of patients. CONCLUSION: The study has shown that improved communication between the CR centres and the GP's after CR had only a marginal effect on the quality of RF-management. One key element of secondary prevention could be to get the patient more strongly involved in reaching the targets of therapy.

Imaging the activity of nitrate reductase by means of a scanning electrochemical microscope.

Scanning electrochemical microscopy (SECM) was used to characterize immobilized nitrate reductase (NaR) from Pseudonomonas stutzeri (E.C. 1.7.99.4). Nitrate reductase with membrane fragment was embedded in a polyurethane hydrogel in a capillary and solubilized NaR without membrane fragment was covalently coupled to a diaminoethyl-cellulose-carbamitate film on glass. After systematic studies of possible mediators, SECM feedback imaging of both forms of immobilized NaR was accomplished with methylviologen as redox mediator.

[Comparison of the pharmacokinetic behavior of Turivital, Acesal and Micristin]. / Vergleich des pharmakokinetischen Verhaltens von Turivital, Acesal und Micristin.

The 3 acetylsalicylic acid preparations showed at normal patients at the same elimination phase no significant differences concerning the bioavailability (comparison of the area under the concentration-time-curve). The absorption kinetics of the preparations were different: the time up to the maximum serum concentration was at Turivital with 1,3 +/- 0,7 h and Micristin (2,1 +/- 0,8 h) the shortest, because the resorption delay was at Turivital the smallest. Absorption constant, fictive initial concentration and maximum concentration in serum are nearly the same in all 3 preparations.

[Stimulation of the renal excretion of p-aminohippuric acid by probenecid homologues (author's transl)]. / Stimulation der renalen PAH-Ausscheidung durch Probenecid-Homologe.

Probenecid and five of its homologues showed increased lipophilicity with increasing chain length of the substituents. Parallel to this, the toxicity increased about 30 times. All the probenecide homologues under study stimulated the excretion of p-aminohippuric acid (PAH) when applied repeatedly. If a threshold dose is exceeded, an increase of the pretreatment dose will not result in a further increase in PAH excretion. As compared to non-pretreated control animals, the highest possible increase in PAH excretion lies between 40 and 80% independently of the structure of the respective probenecide homologue. Due to their more favourable therapeutic range (LD50 divided by D40-50), the probenecide homologues with shorter chains are better suited to stimulate the excretion of PAH, though the extent of stimulation is the same with all the probenicide homologues under study.

Comparison of the effects of cholestyramine and aluminium hydroxide on the biliary bile acid excretion in rats. An experimental model for the depletion of bile acids in bile.

Bile flow and biliary excretion of dihydroxy- and trihydroxy-bile acids have been determined in control, cholestyramine (250--2000 mg/kg p.os)- and aluminium hydroxide (250--2000 mg/kg p.os)-pretreated rats. Cholestyramine proved to be a more potent bile acid depleting agent than aluminium hydroxide. The depressing effect of cholestyramine on bile flow was also more significant than that of aluminium hydroxide. Cholestyramine-pretreatment seemed to be a suitable experimental model for the depletion of bile acids in rat bile.

[Effect of metyrapone on bile flow and bile acid excretion in Wistar rats]. / Einfluss von Metyrapon auf Gallenfluss und Gallensäurenausscheidung bei Wistar-Ratten.

The influence of metyrapone on bile flow and excretion of mono-(MBA), di-(DBA) and trihydroxy-(TBA)-bile acids was investigated in adult male Wistar rats after single and repeated pretreatment. MBA were not found in the rat bile. Metyrapone administration (200 mg/kg b.w. i.p.) 1 h before onset of a 3-hour bile collection period diminished bile flow and excretion of DBA and TBA. The relation TBA/DBA was changed towards DBA. Similar results were found after repeated administration 12 h after the last metyrapone injection (4 x 50 mg/kg b.w. i.p. per day for 4 consecutive days). But 60 h after the last metyrapone administration bile flow and the excretion of TBA were enhanced and the TBA/DBA ratio was changed towards TBA. The possible influence of metyrapone on bile acid hydroxylation is discussed and compared with metyrapone action on hydroxylation of foreign compounds.

[Effect of progesterone and phenylbutazone on bile flow and bile acid excretion in male Wistar rats]. / Einfluss von Progesteron und Phenylbutazon auf Gallenfluss und Gallensäurenausscheidung bei männlichen Wistarratten.

Bile flow and excretion of monohydroxy-, dihydroxy- and trihydroxy bile acids (MBA, DBA and TBA) were estimated after acute and subacute progesterone and phenylbutazone pretreatment in adult male Wistar rats in three one-hour periods. Different pretreatment with sunflower oil did not influence bile flow and excretion of DBA and TBA. MBA were not detected. Different administration of progesterone and phenylbutazone did not significantly change the TBA/DBA ratio. Progesterone administration (50 mg/kg b. w. i. p.) 2 hours before bile sampling increased bile flow and bile acid excretion in the third one-hour period. After 3 days of pretreatment with progesterone (3 X 50 mg/kg b. w. i. p.) bile flow and TBA-excretion were diminished. Phenylbutazone (100 mg/kg b. w. i. p.) increased bile flow and TBA-excretion both after acute and subacute administration.

[Effect of phenobarbital and chlorpromazine on bile flow and bile acid excretion in male Wistar rats]. / Einfluss von Phenobarbital und Chlorpromazin auf Gallenfluss und Gallensäurenausscheidung bei männlichen Wistarratten.

Bile flow and excretion of monohydroxy-, dihydroxy- and trihydroxy-bile acids (MBA, DBA and TBA) were estimated after acute and subacute phenobarbital and chlorpromazine pretreatment in 60-day-old male Wistar rats. Bile was collected in bile-fistula rats in three 1-hour periods. MBA were not detected. Neither single nor repeated ip. administration of different amounts of saline before bile sampling nor oral water supply within the bile collection period influenced the bile flow and excretion of DBA and TBA. Phenobarbital administration (60 mg/kg b.w. ip.) 2 hrs before bile sampling did not influence bile flow and bile acid (BA) excretion. After 3 days pretreatment with phenobarbital (3 X 60 mg/kg b.w. ip.) the bile flow was somewhat increased, BA-excretion was unchanged and the relation TBA/DBA diminished. Chlorpromazine administration (40 mg/kg b.w. ip.) 1,5 hrs before bile sampling decreased bile flow and BA excretion within the first collection period, whereas bile flow and BA excretion increased in the thrid collection period. No signs of cholestasis were observed after chlorpromazine pretreatment once a day for 3 days. Bile flow and BA excretion were increased and the relation TBA/DBA was unchanged.

Influence of drugs on bile acid excretion.

The hydroxylation of bile acids in rat liver microsomes in cyt P-450 dependent (Björkhem et al., 1975). To find out possible interactions between drugs and bile acid hydroxylation and/or active transport mechanisms we investigated the influence of the microsomal inhibitor metyrapon, the microsomal inducer phenobarbital and the intrahepatic cholestasis producing agents chlorpromazine, phenylbutazone and progesteron on bile flow and bile acid excretion. The excretion in monohydroxy (MBA), dihydroxy (DBA) and trihydroxy (TBA) bile acids were estimated in bile-fistula rats in three one hour periods. MBA, DBA and TBA were separated with thinlayer-chromatography and estimated fluorimetrically. Bile flow, bile acid excretion and relation TBA/DBA were influenced by acute and subchronic administration of the above mentioned drugs in different ways.

[Pharmacokinetics of indomethacin and indomethacin metabolites administered continuously to patients with healthy or damaged kidneys]. / Zur Pharmakokinetik von Indomethazin und Indomethazin-metaboliten bei wiederholter Applikation an nierengesunden und nierengeschädigten Patienten.

After oral administration of 75 mg Indomethacin dlimination half-life of the unchanged drug is not altered in patients with severely impaired renal function. In patients with renal insufficiency half-life of Indomethacin plus metabolites is twice that of the normal value. Repeated daily administration of 75 mg for 8 days does not influence Indomethacin kinetics. In the control group and in patients with moderate by impaired renal function Indomethacin half-life does not change during chronic administration.

[Age dependent differences in the pharmacokinetics of furosemide in rats]. / Altersabhängige unterschiede der pharmakokinetik von furosemid bei ratten

After i.p. administration of 0,60 mg/100 g of furosemide, adult rats excreted 50 to 70% of this diuretic drug unchanged and 10% as desfurylmethylfurosemide. The renal excretion of furosemide is slower in 5- and 15-day-old rats. Age differences in absorption from the abdominal cavity or in the reabsorption rate in the kidney tubules can be excluded. The excretion of furosemide by the kidney is competitively inhibited by p-aminohippuric acid (PAH). The relative small inhibitory effect of PAH in young rats is caused by a smaller participation of tubular secretion in the renal excretion of furosemide in this age group. The half life time of furosemide is 83 min in 5-day-old rats and 47 min in 55-day-old rats. The distribution volume is 146% of body weight in both age groups. The concentration of furosemide in the kidney homogenate is higher in young rats than in adults. The slow renal excretion of furosemide in young rats is in accordance with the prolonged efficacy. The greater efficacy of furosemide in 5- and 15-day-old rats than in adults is caused particularly by differences in the conditions for diuretic effectiveness, especially by the retention of water and electrolytes in young rats.

[Age related effects of furosemide in the rat]. / Altersabhängige Wirkungen von Furosemid bei Ratten

Furosemide (6 mg/kg i.p.) increases the renal excretion of water, osmotic active substances, sodium and chloride in 5 to 33 day old rats more than in adults. The dose-response-relations are the same in rats of all age groups: 6 mg/kg of furosemide i.p. are very effective, an increase in dose to 30-60 mg/kg i.p. is not followed by a significantly higher efficacy. The increase in the renal excretion of potassium, hydrogen ions, ammonium and hydrogen carbonate by furosemide is also small in young rats.

[The behavior of the b-wave in the electroretinogram of light-adapted frogs during serial light exposure]. / Das Verhalten der b-Welle im Elektroretinogramm helladaptierter Frösche bei Serienbelichtung

In light-adapted frogs (adaptation luminance 10(3) asb) repeated flashes of high intensity (10(5) asb) caused decrease of the b-wave in the electroretinogram as compared to the results obtained with dark-adapted animals. The amplitude changes were monotonous in all cases; they were dependent on the spacing and duration of the stimulus. With short intervals (2-10 sec) the amplitude adjusted to a new level no later than after 8 flashes. With longer intervals (30 and 60 sec), however, the amplitude decreased slowly and steadily over the whole period of experiment. Under these conditions, adjustment to a new level was prevented by disturbing factors, which additionally reduced the retinal sensitivity depending on the duration of the experiment.