Attosecond clocking of correlations between Bloch electrons.

Delocalized Bloch electrons and the low-energy correlations between them determine key optical1, electronic2 and entanglement3 functionalities of solids, all the way through to phase transitions4,5. To directly capture how many-body correlations affect the actual motion of Bloch electrons, subfemtosecond (1 fs = 10-15 s) temporal precision6-15 is desirable. Yet, probing with attosecond (1 as = 10-18 s) high-energy photons has not been energy-selective enough to resolve the relevant millielectronvolt-scale interactions of electrons1-5,16,17 near the Fermi energy. Here, we use multi-terahertz light fields to force electron-hole pairs in crystalline semiconductors onto closed trajectories, and clock the delay between separation and recollision with 300 as precision, corresponding to 0.7% of the driving field's oscillation period. We detect that strong Coulomb correlations emergent in atomically thin WSe2 shift the optimal timing of recollisions by up to 1.2 ± 0.3 fs compared to the bulk material. A quantitative analysis with quantum-dynamic many-body computations in a Wigner-function representation yields a direct and intuitive view on how the Coulomb interaction, non-classical aspects, the strength of the driving field and the valley polarization influence the dynamics. The resulting attosecond chronoscopy of delocalized electrons could revolutionize the understanding of unexpected phase transitions and emergent quantum-dynamic phenomena for future electronic, optoelectronic and quantum-information technologies.

Super-resolution lightwave tomography of electronic bands in quantum materials.

Searching for quantum functionalities requires access to the electronic structure, constituting the foundation of exquisite spin-valley-electronic, topological, and many-body effects. All-optical band-structure reconstruction could directly connect electronic structure with the coveted quantum phenomena if strong lightwaves transported localized electrons within preselected bands. Here, we demonstrate that harmonic sideband (HSB) generation in monolayer tungsten diselenide creates distinct electronic interference combs in momentum space. Locating these momentum combs in spectroscopy enables super-resolution tomography of key band-structure details in situ. We experimentally tuned the optical-driver frequency by a full octave and show that the predicted super-resolution manifests in a critical intensity and frequency dependence of HSBs. Our concept offers a practical, all-optical, fully three-dimensional tomography of electronic structure even in microscopically small quantum materials, band by band.

The relationship between initial closed reduction and the surgical reconstruction of the radiocarpal joint line in distal radial fractures.

INTRODUCTION: Whilst initial closed reduction followed by definitive open fixation is widely applied in the treatment of distal radial fractures, the effect of the closed reduction on the reconstruction of the articular surface remains unclear. Our research questions were: METHODS: Palmar tilt and radiocarpal inclination of 425 patients were measured at admission, following initial closed reduction and after surgical reconstruction. RESULTS: Closed reduction increased palmar tilt by 12.1° and radial inclination by 2.7°. Open surgical reduction further corrected palmar tilt by 17.88° and radial inclination by 3.5°. Whilst there was no association between postoperative palmar tilt and initially achieved closed reduction, a significant association between radial inclination following closed reduction and surgical fixation was found. CONCLUSION: Our retrospective study challenges the existence of a relationship between the initial closed reduction and the reconstruction of the anatomic joint line in surgically treated distal radial fractures.

[Additional treatment supporting standard care for children and adolescents with diabetes mellitus type I - indication, acceptance and outcome: results from a multi-centre observational study]. / Interventionen zur Unterstützung der Regelversorgung von Kindern und Jugendlichen mit Diabetes Typ I - Indikationen, Inanspruchnahme und Effekte: Ergebnisse einer multizentrischen Beobachtungsstudie.

BACKGROUND: At various time points of routine care, additional treatment beyond standard care is required for patients with special problems (i.e. diabetes training, counselling and/or psychological support). Despite the frequency of such additional interventions, there is little information about the outcome of such measures. PATIENTS/METHODS: In an observational study, data from 765 children/adolescents and their parents were collected. The collection included data on patients&' quality of life, their psychosocial situation as well as somatic parameters (metabolic control). Members of the diabetes team rated the necessity and the realisation of interventions in addition to standard care. 22 treatment centers, providing community-based diabetes care, participated in the study. The age of the patients averaged 11.5+/-3.7 years, the average duration of diabetes was 3.7+/-3.2 years; the mean HbA1C was 7.5+/-1.3%. The effects of the additional treatment were evaluated based on the view of the diabetes care team, and based on serial HbA1C measurements (average duration between inclusion in the study and follow-up was 1.16+/-0.17 years). RESULTS: For 197 patients (25.7%) additional treatment was recommended by the diabetes team. In particular, both out-patient and in-patient diabetes training courses as well as psychological support were suggested. 69.6% of the patients followed these recommendations and accepted additional treatment. The largest effects of additional treatment were seen by the team in respect to metabolic improvement and patient compliance. The smallest effects were observed with respect to changes in behaviour and in the family situation. By using the HbA1C values as an objective criterion, however, no marked improvement in metabolic control of patients receiving additional treatment was present. The kind of additional treatment recommended did not affect the outcome, and no difference was present whether the additional intervention was actually completed or not. Metabolic control deteriorated during the observation period by+0.5+/-1.3% in patients were additional intervention had been recommended, compared to+0.16+/-1.1% in patients were no additional treatments had been recommended (p=0.002). There was no significant correlation between the judgment of the diabetes team on metabolic improvement and the HbA1c change during the observation period (r=0.11). CONCLUSIONS: These data demonstrate that many patients have problems to cope with diabetes management. Standard diabetes care is often not sufficient and patients need additional support. The results also show that the additional interventions recommended only have a moderate or minor effect on outcome. We conclude from these results that it is necessary to attend to the needs of the patients and anchor the recommendation on treatment in the standard care environment. We need a qualitatively better interconnection of multiple therapeutic approaches, in combination with the necessity for permanent monitoring of the efficiency of all interventions.

Subunit movement in individual H+-ATP synthases during ATP synthesis and hydrolysis revealed by fluorescence resonance energy transfer.

F-type H+-ATP synthases synthesize ATP from ADP and phosphate using the energy supplied by a transmembrane electrochemical potential difference of protons. Rotary subunit movements within the enzyme drive catalysis in either an ATP hydrolysis or an ATP synthesis direction respectively. To monitor these subunit movements and associated conformational changes in real time and with subnanometre resolution, a single-molecule FRET (fluorescence resonance energy transfer) approach has been developed using the double-labelled H+-ATP synthase from Escherichia coli. After reconstitution into a liposome, this enzyme was able to catalyse ATP synthesis when the membrane was energized.

Binding of single nucleotides to H+-ATP synthases observed by fluorescence resonance energy transfer.

F(0)F(1)-ATP synthases couple proton translocation with the synthesis of ATP from ADP and phosphate. The enzyme has three catalytic nucleotide binding sites, one on each beta-subunit; three non-catalytic binding sites are located mainly on each alpha-subunit. In order to observe substrate binding to the enzyme, the H(+)-ATP synthase from Escherichia coli was labelled selectively with the fluorescence donor tetramethylrhodamine (TMR) at position T106C of the gamma-subunit. The labelled enzymes were incorporated into liposomes and catalysed proton-driven ATP synthesis. The substrate ATP-Alexa Fluor 647 was used as the fluorescence acceptor to perform intermolecular fluorescence resonance energy transfer (FRET). Single molecules are detected with a confocal set-up. When one ATP-Alexa Fluor 647 binds to the enzyme, FRET can be observed. Five stable states with different intermolecular FRET efficiencies were distinguished for enzyme-bound ATP-Alexa Fluor 647 indicating binding to different binding sites. Consecutive hydrolysis of excess ATP resulted in stepwise changes of the FRET efficiency. Thereby, gamma-subunit movement during catalysis was directly monitored with respect to the binding site with bound ATP-Alexa Fluor 647.

Microstructuring of solid-supported lipid layers using SAM pattern generation by scanning electrochemical microscopy and the chemical lens.

To prepare patterns of adsorption sites for alkanethiols with high lateral resolution, we used the scanning electrochemical microscopy (SECM) to etch masks into uniform layers of nickel coated on gold surfaces. The patterning of the nickel mask was accomplished in aqueous solutions by electrogenerating nitric acid out of nitrite at an ultramicroelectrode. Due to the sluggish kinetics of nickel etching in acidic media, the pattern generated by a 10-microm tip was about 50-microm wide, depending on the duration of the etching. As an alternative, applying the principle of the chemical lens by adding potassium hydroxide as a scavenger, the size of the adsorption sites had been reduced to 4 microm, independent of the duration of etching. In a follow-up step, monolayers of 11-mercaptoundecanoic acid were formed on the exposed gold areas of the surface by self-assembly. Fluorescent liposomes containing tetramethylrhodamine-labeled phospholipids were used to create solid-supported lipid layers (SSLLs). These fluorescent liposomes showed a selective binding affinity to the self-assembled monolayers (SAMs) modified areas, but not to the nickel surface. The patterns generated were imaged by the SECM itself, as well as by optical and fluorescence microscopy.

Conformational changes of the H+-ATPase from Escherichia coli upon nucleotide binding detected by single molecule fluorescence.

Using a confocal fluorescence microscope with an avalanche photodiode as detector, we studied the fluorescence of the tetramethylrhodamine labeled F1 part of the H+-ATPase from Escherichia coli, EF1, carrying the gammaT106-C mutation [Aggeler, J.A. and Capaldi, R.A. (1992) J. Biol. Chem. 267, 21355-21359] in aqueous solution upon excitation with a mode-locked argon ion laser at 528 nm. The diffusion of the labeled EF1 through the confocal volume gives rise to photon bursts, which were analyzed with fluorescence correlation spectroscopy, resulting in a diffusion coefficient of 3.3 x 10(-7) cm2 s(-1). In the presence of nucleotides the diffusion coefficient increases by about 15%. This effect indicates a change of the shape and/or the volume of the enzyme upon binding of nucleotides, i.e. fluorescence correlation spectroscopy with single EF1 molecules allows the detection of conformational changes.

Resistance trained athletes using or not using anabolic steroids compared to runners: effects on cardiorespiratory variables, body composition, and plasma lipids.

OBJECTIVE: To determine whether there is a difference in cardiac size and function as well as in body composition, aerobic capacity, and blood lipids between resistance trained athletes who use anabolic steroids and those who do not, and to compare them to university cross country athletes. METHODS: Four groups of men were evaluated: recreational lifters, n = 11, lifting < 10 h.week-1; heavy lifters, n = 16, lifting > 10 h.week-1; steroid users, n = 8, same as heavy lifters and used steroids; runners, n = 8, university track members. Echocardiograms, body composition (hydrostatic weighing), maximum oxygen consumption (Vo2), and lipids were studied. RESULTS: As expected, Vo2 (ml.kg-1.min-1), was greatest in the runners, with no difference among the lifting groups. High density lipoprotein cholesterol in the steroid user group was lower than in heavy lifters or runners. Left ventricular internal diastolic dimension was similar among the groups. The left ventricular mass index of the steroid user group was significantly greater than recreational lifters, at 161 v 103. There was no difference among heavy lifters (127), runners (124), and steroid users. There was no compromise in diastolic function in any group. There were no differences among groups in resting or exercise blood pressure. CONCLUSIONS: Resistance training in the absence of steroid use results in the same positive effects on cardiac dimensions, diastolic function, and blood lipids as aerobic training.

The prehospital phase of acute myocardial infarction in the era of thrombolysis.

To evaluate the factors affecting the time between symptom onset and hospital arrival in patients with acute myocardial infarction (AMI), we gave a detailed questionnaire to all who were admitted or transferred with AMI from January 1988 to February 1989. In these 126 patients (94 men, 32 women) the mean prehospital time was 5.9 +/- 11.0 hours (median 2.0, range 0.4 to 69.0). The time between symptom onset and reaching a decision that medical care should be sought was 62% of the mean prehospital time. In 100 (79%) patients, the prehospital time was less than or equal to 6 hours; of these, 61 (61%) were retrospectively judged to have been optimal candidates for lytic therapy. Stepwise multiple regression selected the following 4 variables as independent predictors of prehospital time: slow symptom progression; low income; female gender; and advanced age. All of these variables are predictive (p less than 0.03) of increased prehospital time; absence of prior AMI was of borderline additional significance (p = 0.053). Similarly, logistic regression analysis selected slow symptom progression, female gender and low income as significant (p less than or equal to 0.02) independent predictors of prehospital time greater than 6 hours. The logistic regression model incorporating these 3 variables had a sensitivity of 54%, a specificity of 95% and a positive predictive value of 72% in identifying patients with prehospital time greater than 6 hours. Thus, these data indicate it is possible to characterize patients likely to experience undue prehospital delay during AMI, which may be of importance to future public education efforts.