A Large Effective Phonon Magnetic Moment in a Dirac Semimetal.

We investigated the magnetoterahertz response of the Dirac semimetal Cd3As2 and observed a particularly low frequency optical phonon as well as a very prominent and field-sensitive cyclotron resonance. As the cyclotron frequency is tuned with the field to pass through the phonon, the phonon becomes circularly polarized, as shown by a notable splitting in its response to right- and left-hand polarized light. This splitting can be expressed as an effective phonon magnetic moment that is approximately 2.7 times the Bohr magneton, which is almost 4 orders of magnitude larger than ab initio calculations predict for phonon magnetic moments in nonmagnetic insulators. This exceedingly large value is due to the coupling of the phonons to the cyclotron motion and is controlled directly by the electron-phonon coupling constant. This field-tunable circular-polarization-selective coupling provides new functionality for nonlinear optics to create light-induced topological phases in Dirac semimetals.

Selective-area catalyst-free MBE growth of GaN nanowires using a patterned oxide layer.

GaN nanowires (NWs) were grown selectively in holes of a patterned silicon oxide mask, by rf-plasma-assisted molecular beam epitaxy (PAMBE), without any metal catalyst. The oxide was deposited on a thin AlN buffer layer previously grown on a Si(111) substrate. Regular arrays of holes in the oxide layer were obtained using standard e-beam lithography. The selectivity of growth has been studied varying the substrate temperature, gallium beam equivalent pressure and patterning layout. Adjusting the growth parameters, GaN NWs can be selectively grown in the holes of the patterned oxide with complete suppression of the parasitic growth in between the holes. The occupation probability of a hole with a single or multiple NWs depends strongly on its diameter. The selectively grown GaN NWs have one common crystallographic orientation with respect to the Si(111) substrate via the AlN buffer layer, as proven by x-ray diffraction (XRD) measurements. Based on the experimental data, we present a schematic model of the GaN NW formation in which a GaN pedestal is initially grown in the hole.

[Successful therapy of discoid lupus erythematosus with efalizumab]. / Erfolgreiche Therapie eines diskoiden Lupus erythematodes mit Efalizumab.

The therapy of discoid lupus erythematosus (DLE) is occasionally a therapeutic challenge. Topical treatment is often not sufficient and therapy with antimalarials [(hydroxy-) chloroquine] not always successful. We report on a 50-year-old male patient with recalcitrant chronic DLE who experienced within 12 weeks at first improvement and then almost complete remission for 11 months after off-label application of the anti-CD11a antibody efalizumab.

Validity and clinical feasibility of the ADHD rating scale (ADHD-RS) A Danish Nationwide Multicenter Study.

AIM: To establish the validity of a Danish version of the Attention Deficit Hyperactivity Disorder Rating Scale (ADHD-RS), secondly to present national norm scores compared to that of United States and other European data and thirdly to evaluate ADHD-RS when used for monitoring treatment effectiveness. METHODS: A Danish translation of the ADHD-RS was used on a normative sample of 837 children. Two clinical samples, 138 hyperkinetic disorder (HKD) cases and 110 clinical controls were recruited from eleven Danish Child and Adolescent Mental Health (CAMH) centres and assessed according to usual clinical standards. The HKD children were rated by parents and teachers at baseline and at follow-up 3 months later. RESULTS: Internal validity of ADHD-RS was high and the factor structure supported the diagnostic classification system ICD-10. The questionnaire discriminated HKD patients in a mixed clinical sample, and was sensitive to change in symptom load as measured before and after commencing of the treatment. CONCLUSION: The Danish version of ADHD-RS is valid and clinically feasible when measuring HKD symptom load in a CAMH-setting. The questionnaire provides useful data in patient management, quality improvement and service planning as well as in effectiveness studies of different interventions for patients with HKD and related disorders in routine clinical settings.

Intubating laryngeal mask airway, laryngeal tube, 1100 ml self-inflating bag-alternatives for basic life support?

Insufficient oxygenation, ventilation and gastric inflation with subsequent regurgitation of stomach contents is a major hazard of bag-valve-face mask ventilation during the basic life support phase of cardiopulmonary resuscitation (CPR). The European Resuscitation Council has recommended smaller tidal volumes of approximately 500 ml as an effort to reduce gastric inflation; furthermore, the intubating laryngeal mask airway and the laryngeal tube have been recently developed in order to provide rapid ventilation and to secure the airway. The purpose of our study was to examine whether usage of a newly developed medium-size self-inflating bag (maximum volume, 1100 ml) in association with the intubating laryngeal mask airway, and laryngeal tube may provide adequate lung ventilation, while reducing the risk of gastric inflation in a bench model simulating the initial phase of CPR. Twenty house officers volunteered for our study. When using the laryngeal tube, and the intubating laryngeal mask airway, respectively, the medium-size (maximum volume, 1100 ml) versus adult (maximum volume, 1500 ml) self-inflating bag resulted in significantly (P<0.05) lower mean+/-S.E.M. lung tidal volumes (605+/-22 vs. 832+/-4 ml, and 666+/-27 vs. 887+/-37 ml, respectively), but comparable peak airway pressures. No gastric inflation occurred when using both devices with either ventilation bag. In conclusion, both the intubating laryngeal mask airway and laryngeal tube in combination with both an 1100 and 1500 ml maximum volume self inflating bag proved to be valid alternatives for emergency airway management in a bench model of a simulated unintubated cardiac arrest victim.

Emergency medical service transport-induced stress? An experimental approach with healthy volunteers.

This randomized controlled trial was designed to evaluate the effects of simulated emergency medical service (EMS) transport related stress on hemodynamic variables, and catecholamine plasma levels. A total of 32 healthy male volunteers were randomized to being carried by paramedics from a third-floor apartment through a staircase with subsequent high-speed EMS transport with lights and sirens (stress; n = 16); or sitting on a chair for 5 min, and lying on a stretcher for 15 min (control; n = 16). Blood samples and hemodynamic variables were taken in the apartment before transfer, at the ground floor, and at the end of EMS transport in the stress group, and at corresponding time points in the control group. The stress versus control group had both significantly (P < 0.05) higher mean +/- SEM epinephrine (71 +/- 7 versus 37 +/- 3 pg/ml), and norepinephrine (397 +/- 29 versus 299 +/- 28 pg/ml) plasma levels after transport through the staircase. After EMS transport, the stress versus control group had significantly higher epinephrine (48 +/-6 versus 32 +/- 2 pg/ml), but not norepinephrine (214 +/- 20 versus 264 +/- 31 pg/ml) plasma levels. Heart rate increased significantly from 72 +/- 2 to 84 +/- 3 bpm after staircase transport, but not during and after EMS transport. In conclusion, volunteers being carried by paramedics through a staircase had a significant discharge of both epinephrine and norepinephrine resulting in increased heart rate, but only elevated epinephrine plasma levels during EMS transport. Transport through a staircase may reflect more stress than emergency EMS transport.

[Emergency airway management-- comparison of various strategies in an unsecured airway]. / Notfall-Atemwegs-Management--eine vergleichende Untersuchung verschiedener Strategien bei ungesichertem Luftweg.

OBJECTIVES: Gastric inflation and regurgitation of stomach contents are major hazards of bag-valve-mask ventilation in an emergency. The purpose of our study was to determine lung ventilation and gastric inflation when using the bag-valve-face mask, laryngeal mask, and combitube with different sizes of self-inflating bags (max. volume: 700, 1100, 1500 ml). METHODS: Twenty-six training emergency doctors without prior extensive training in emergency airway management volunteered for our study and ventilated a bench model simulating an unintubated respiratory arrest patient with bag-valve-face mask, laryngeal mask, and combitube using paediatric, medium size, and adult self-inflating bags. Lung and gastric tidal volume, as well as lung and gastric peak airway pressure were measured with respiratory monitors and a pneumotachometer. RESULTS: When using either the combitube or the laryngeal mask, the paediatric vs. medium-size and adult self-inflating bag resulted in significantly (P < .001) lower mean +/- SEM lung tidal volumes (328 +/- 34 vs. 626 +/- 65 vs. 654 +/- 69 ml; and 368 +/- 30 vs. 532 +/- 48 vs. 692 +/- 67 ml, respectively). No gastric inflation occurred with the combitube, while gastric inflation was comparably low when using the laryngeal mask with either ventilation bag (3 +/- 2 vs. 7 +/- 4 vs. 6 +/- 3 ml; P = NS). The paediatric vs. medium-size and adult self-inflating bag in combination with the bag-valve-face mask resulted in comparable lung tidal volumes (250 +/- 23 vs. 313 +/- 24 vs. 282 +/- 38 ml; P = NS); but significantly (P < .01) lower gastric tidal volumes (147 +/- 23 vs. 206 +/- 24 vs. 267 +/- 23 ml). CONCLUSIONS: Both the laryngeal mask and the combitube proved to be valid alternatives for the bag-valve-face mask in our experimental model. The medium size self-inflating bag seems to be adequate when using either the laryngeal mask or the combitube.

Decrease of CA 19-9 during chemotherapy with gemcitabine predicts survival time in patients with advanced pancreatic cancer.

Chemotherapy with gemcitabine has been shown to be an effective regimen in advanced or metastatic pancreatic cancer with improvement of both quality of life and survival time. The response of the tumour marker CA 19-9 to chemotherapy with gemcitabine was studied in order to find out whether it is related to survival time of patients. Forty-three consecutive patients (median age 61 years, range 39-76 years; 20 males, 23 females) suffering from histologically proven locally advanced or metastatic pancreatic adenocarcinoma and a baseline Karnofsky-index > or = 60 were treated with gemcitabine in a dose of 1,000 mg/m(-2) weekly x 7 followed by 1 week of rest during the first cycle and thereafter 1,000 mg/m(-2) weekly x 3 followed by 1 week of rest until progression. In 36 of 43 patients serial measurements of CA 19-9 could be performed. Patients with a decrease of > 20% of the baseline CA 19-9 level after 8 weeks of treatment (n = 25) had a significantly better median survival than patients with a rise or a decrease < or = 20% (n = 11) (268 vs 110 days; P < 0.001). The response of CA 19-9 was the strongest independent predictor of survival (P < 0.001) in the multivariate analysis. In conclusion, a decrease of CA 19-9 > 20% during the first weeks of chemotherapy with gemcitabine is associated with a better survival of patients with locally advanced or metastatic pancreatic cancer. Serial measurements of CA 19-9 are useful to decide whether further chemotherapy after the first weeks of treatment is indicated.

Interlaboratory variability of rotational chair test results II: analysis of simulated data.

Standardization of rotational chair testing across laboratories has not been achieved because of differences in test protocol and analysis algorithms. The Interlaboratory Rotational Chair Study Group was formed to investigate these differences. Its first study demonstrated significant variability in calculated results using actual patient data files. No estimation of accuracy could be made, however, because the "true" values of response parameters were unknown. In this study we used simulated "patient" data files to further explore the differences among analysis algorithms. We found a high degree of agreement and accuracy across laboratories using automated analysis of high signal-to-noise/low-artifact data for gain, phase, and asymmetry. Variability increased significantly for the lower signal-to-noise ratio/higher artifact files. Operator intervention generally improved accuracy and decreased variability, but there were cases in which operator intervention reduced accuracy.

The Escherichia coli SlyD is a metal ion-regulated peptidyl-prolyl cis/trans-isomerase.

In Escherichia coli as many as nine different genes coding for proteins with significant homology to peptidyl-prolyl cis/trans-isomerases (PPIases) have been found. However, for three of them, the histidine-rich SlyD, the homologous gene product of ORF149, and parvulin-like SurA, it was not known whether these proteins really possess PPIase activity. To gain access to the full set of PPIases in E. coli, SlyD, the N-terminal fragment of SlyD devoid of the histidine-rich region, as well as the protein product of ORF149 of E. coli named SlpA (SlyD-like protein) were cloned, overexpressed, and purified to apparent homogeneity. On the basis of the amino acid sequences, both proteins proved to be of the FK506-binding protein type of PPIases. Only when using trypsin instead of chymotrypsin as helper enzyme in the PPIase assay, the enzymatic activity of full-length SlyD and its N-terminal fragment can be measured. For Suc-Ala-Phe-Pro-Arg-4-nitroanilide as substrate, kcat/Km of 29,600 M-1 s-1 for SlyD and 18,600 M-1 s-1 for the N-terminal fragment were obtained. Surprisingly, the PPIase activity of SlyD is reversibly regulated by binding of three Ni2+ ions to the histidine-rich, C-terminal region. Because the PPIase activity of SlpA could be established as well, we now know eight distinct PPIases with proven enzyme activity in E. coli.

Time-frequency analysis of postural sway.

Postural sway during quiet stance has been used to characterize the postural control system. Most studies have used center of pressure (COP) measurements and have assumed stationarity, however, recent research has indicated that COP is not stationary. The purpose of this study is to introduce and demonstrate a nonstationary spectral estimation technique to examine the time-varying nature of postural sway. Data from two experiments were used to verify the usefulness of the spectral estimator for the analysis of COP. The first data set contains COP recorded from normal subjects swaying about their ankles in response to a metronome as it was gradually changed from 2 to 1 Hz. The time-frequency distribution reveals time-varying spectral changes corresponding to frequency changes made by the subjects. The second set consists of COP from normal subjects and vestibularly impaired patients standing quietly on a force plate with eyes closed for 100 s. The time-frequency distributions for the COP were estimated for both sets of data. The COP's appear to be nonstationary with the energies at a given frequency modulating through time.

A model of foot placement during gait.

Foot placement is known to affect balance during gait; however, how foot placements are chosen is unknown. Objectives of this research were to analyze swing trajectories of the foot during gait with respect to the pelvis, and to propose a model of foot placement control which provides a stable base of support. Effects of gait speed and vision on this model of foot placement were then examined. Foot trajectories were analyzed using spherical coordinates referenced to the pelvis, termed the pelvic spherical coordinates (PSCs). A model was developed based on this coordinate system which predicts foot placement in terms of position and velocity with respect to the pelvis. It is proposed that foot placements are chosen to minimize the sum of PSC coordinates of the stance and swing feet. Foot velocity at heel contact is proposed to minimize the sum of the PSC stance and swing angular velocities. Experimental data were collected to test this model during walking trials of different speeds, both with and without vision. Results showed that sums of stance and swing feet PSCs were very close to zero at heel contact, supporting the positional control hypothesis. Sums of PSC velocities, however, were not zero at heel contact. Rather, individual swing leg PSC velocities were zero at heel contact, suggesting independent swing leg velocity control. Vision did not have an effect on position or velocity variables at heel contact. Gait speed did have an effect, particularly on PSC velocities at heel contact.(ABSTRACT TRUNCATED AT 250 WORDS)

Interlaboratory variability of rotational chair test results. Interlaboratory Rotational Chair Study Group.

Test-retest reliability of rotational chair testing for a single facility has previously been examined by others. The actual data analysis methods, however, have received far less attention. The variety of both hardware and software currently used theoretically may affect the results for a given subject tested at different facilities. The purposes of this study were, first, to quantify the amount of variability in the analysis of identical raw data files at multiple rotational chair testing facilities by using automated analysis; second, to evaluate the effect of operator intervention on the analysis; and third, to identify possible sources of variability. Raw data were collected from 10 normal subjects at 0.05 Hz and 0.5 Hz (50 degrees per second peak velocity). Diskettes containing raw electro-oculogram data files were then distributed to eight participating laboratories for analysis by two methods: (1) using automated analysis algorithms and (2) using the same algorithms but allowing operator intervention into the analysis. Response parameters calculated were gain and phase (re: velocity). The SD of gain values per subject for automated analysis ranged from 0.01 to 0.32 gain units and of phase values from 0.4 to 13.7 degrees. For analysis with operator intervention, the SD of gain values ranged from 0.02 to 0.10 gain units and of phase values from 0.4 to 4.4 degrees. The difference between automated analysis and analysis with operator intervention was significant for gain calculations (p < 0.02) but not for phase calculations (p > 0.05). This study demonstrates significant variability in automated analysis of rotational chair raw data for gain and phase.(ABSTRACT TRUNCATED AT 250 WORDS)

Off-vertical axis rotation: a test of the otolith-ocular reflex.

The vestibulo-ocular reflex was studied via off-vertical axis rotation (OVAR) in the dark. The axis of the turntable could be tilted from vertical by up to 30 degrees. Eye movements were measured with electro-oculography. Results from healthy asymptomatic subjects indicated that 1) a reliable otolith-induced response could be obtained during constant velocity OVAR using a velocity of 60 degrees/s with a tilt of 30 degrees; 2) constant velocity OVAR rotation was nausea-producing and, especially if subjects were rotated in the dark about an earth-vertical axis prior to being tilted, disorienting; and 3) sinusoidal OVAR produced minimal nausea; the eye movement response appeared to be the result of a combination of semicircular canal and otolith components. We conclude that OVAR has the potential of becoming a useful method for clinically assessing both the otolith-ocular reflex and semicircular canal-otolith interaction.

Environmental control unit utilization by high-level spinal cord injured patients.

The study was designed to evaluate the use of an environmental control unit (ECU) by high-level spinal cord injured patients. The technology is relatively new, and to the best of the authors' knowledge, no comprehensive study has been made of the utility of the ECU. Data were obtained from 29 high-level spinal cord injured persons who had been using ECUs for at least one year. The subjects had a mean age of 24.2 years; 89.7% were men; and 51.7% of the injuries resulted from vehicular accidents. Most (93%) of the subjects perceived the ECU as increasing their independence. Operation of the telephone was indicated as the most important function (61%); control of television sets were second (21%) in rank. Of the subjects who worked or went to school, only two used their ECUs for those purposes. Subjects felt comfortable for longer periods without attendant care when the ECU was available. Some of the subjects felt that they had received inadequate training (30%) and that their attendants lacked understanding of the ECU (36%). Steps should be taken to increase the employment potential of ECU users by providing units with additional features and by increasing the training of both users and their attendants. Design of units that are more "user friendly" is also needed.