G Pichler

Publications (90)104.12 Total impact

• Article: Non-nutritives Saugen am Beruhigungsschnuller

  Marie Hanzer, H. Zotter, W. Sauseng, G. Pichler, W. Müller, R. Kerbl
  Pädiatrie & Pädologie 04/2012; 45(1):12-15.
• Article: Characterization of an optical frequency comb using modified direct frequency comb spectroscopy

  D. Aumiler, T. Ban, N. Vujičić, S. Vdović, H. Skenderović, G. Pichler
  [show abstract] [hide abstract]
  ABSTRACT: We introduce a method for determination of the absolute frequencies of comb lines within an optical frequency comb spectrum. The method utilizes the experimental and theoretical approach of the velocity-selective optical pumping of the atomic ground state hyperfine levels induced by resonant pulse-train excitation. The information on the laser pulse repetition frequency and carrier–envelope offset are physically mapped onto the 87Rb ground state hyperfine level population velocity distributions. Theoretical spectra are calculated using an iterative analytic solution of the optical Bloch equations describing the resonant pulse-train excitation of four-level 87Rb atoms. They are employed to fit the measured spectra and obtain the parameters of the frequency comb, thus providing a practical algorithm which can be used in real-time measurements.
  Applied Physics B 04/2012; 97(3):553-560. · 2.19 Impact Factor
• Article: Low-density plasma channels generated by femtosecond pulses

  N. Vujičić, H. Skenderović, T. Ban, D. Aumiler, G. Pichler
  [show abstract] [hide abstract]
  ABSTRACT: We present an investigation of the plasma channel formed along the trail of an intense femtosecond (fs) laser pulse propagating through helium, air and nitrogen at low pressures. The lifetime of the generated plasma channel of up to 60μs was measured. We determined the electron-attachment mechanism as a dominant mechanism for the plasma relaxation. The initial electron densities, electron-attachment coefficients and plasma channel conductivity for different experimental conditions were obtained.
  Applied Physics B 04/2012; 82(3):377-382. · 2.19 Impact Factor
• Article: Blue satellite bands of KRb molecule: Intermediate long-range states

  H. Skenderović, R. Beuc, T. Ban, G. Pichler
  [show abstract] [hide abstract]
  ABSTRACT: Three distinct satellite bands at 730–736 nm and a single shoulder at 755.5 nm that we assigned to KRb heteronuclear molecule are found in absorption measurements of hot K + Rb vapor. The interpretation of these bands is discussed in terms of recent ab initio calculations of the relevant potential curves. Semiclassical spectral simulations were performed with ab initio potentials and approximate transition dipole moment functions showing a good agreement with observations. The probabilities of cold molecule photoassociative formation into the external well of the double minimum (5)0+ state and decay to the ground state are discussed, and relative yields of molecular formation were estimated by using quantum mechanical calculations.
  The European Physical Journal D 04/2012; 19(1):49-56. · 1.48 Impact Factor
• Source

  Available from: Georg Schmölzer

  Article: Multi-modal approach to prophylaxis of necrotizing enterocolitis: clinical report and review of literature

  G. Schmolzer, B. Urlesberger, Michaela Haim, J. Kutschera, G. Pichler, E. Ritschl, B. Resch, F. Reiterer, W. Müller
  [show abstract] [hide abstract]
  ABSTRACT: For the first time a multimodal approach to NEC prophylaxis is reported, consisting of early trophic feeding with human breast milk, and enteral administration of an antibiotic, an antifungal agent, and probiotics. A retrospective analysis of local protocol of NEC prophylaxis is presented. Included were all VLBWI admitted to the NICU, including transfers within the first 28days of life. These infants were divided into two groups, an “inborn group” (infants admitted within the first 24h of life) and an “outborn group” (infants admitted after the onset of their second day of life). Prophylaxis of NEC according to protocol was started at the day of admission, and was continued until discharge. Between 1998 and 2004, 405 VLBWI were admitted, including all transfers within the first 28days of life. A total of 334 (82%) infants were admitted within the first 24h of life (inborn group), and 71 (18%) were admitted after 24h of life (outborn group). Five infants developed clinical features of necrotizing enterocolitis. The inborn group showed a NEC incidence of 0.7% (two infants), whereas the outborn group showed a NEC incidence of 4.5% (three infants), respectively. This difference was significant (P=0.049, Fisher’s exact test). A surgical treatment with bowel resection was performed in two infants (both from the outborn group). The present study used a combination of different strategies, all having shown to have some beneficial effect, but not having brought a clinical breakthrough in single administration studies. Combinated were the beneficial effects of human breast milk feeding, oral antiobiotics, oral antifungal agents, and the administration of probiotics. In a homogenous group of preterm infants, using this protocol of multimodal NEC prophylaxis, there was a very low incidence of NEC, when started within the first 24h of life.
  Pediatric Surgery International 04/2012; 22(7):573-580. · 1.25 Impact Factor
• Article: Coherent population dynamics in rubidium atoms excited by resonant 0π pulses

  T. Ban, D. Aumiler, S. Vdović, N. Vujičić, H. Skenderović, G. Pichler
  [show abstract] [hide abstract]
  ABSTRACT: We investigate the time dynamics of a four-level rubidium atomic system excited by a train of 0π pulses. Resonant 0π pulse shaping is achieved by propagation of weak femtosecond pulses through rubidium vapor and characterized using frequency-resolved optical gating and within the linear dispersion theory. The excitation of the Rb atoms by 0π pulse train is studied experimentally by modified direct frequency comb spectroscopy and theoretically within the density-matrix approach. We show that accumulation of populations and coherences, as typical pulse train excitation effects, strongly depend on the strength of the resonant 0π pulse shaping. Stronger pulse shaping reduces the coherent accumulation effects, eventually leading to the disappearance of the velocity selective optical pumping observed in the frequency domain.
  Phys. Rev. A. 08/2009; 80(2).
• Source

  Available from: Georg Schmölzer

  Article: Comparison of peripheral and cerebral tissue oxygenation index in neonates.

  K Grossauer, G Pichler, G Schmölzer, H Zotter, W Mueller, B Urlesberger
  Archives of Disease in Childhood - Fetal and Neonatal Edition 04/2009; 94(2):F156. · 3.05 Impact Factor
• Source

  Available from: Hrvoje Skenderovic

  Chapter: Cancellation of the coherent accumulation in rubidium atoms excited by a train of femtosecond pulses

  T. Ban, D. Aumiler, H. Skenderovic, S. Vdovic, N. Vujicic, G. Pichler
  [show abstract] [hide abstract]
  ABSTRACT: In present experiments gradual change from the frequency comb excitation to pulse by pulse excitation of Rb atoms is observed. Shown results could lead to the development of a new method for system coherence monitoring.
  12/2008: pages 876-878;
• Article: Recommendations to increase the validity and comparability of peripheral measurements by near infrared spectroscopy in neonates. 'Round table', section of haematology, oxygen transport and microcirculation, 48th annual meeting of ESPR, Prague 2007.

  G Pichler, M Wolf, C Roll, M A Weindling, G Greisen, S P Wardle, P Zaramella, G Naulaers, A Pellicer, T Austin, M Bartocci, B Urlesberger
  [show abstract] [hide abstract]
  ABSTRACT: Several studies of peripheral measurements with near infrared spectroscopy (NIRS) and venous or arterial occlusion have been performed in neonates. Results have been variable. Reasons include differences in patient populations, technical aspects of the devices used or the way measurements were made. It is therefore important that there should be common elements for measurement protocols. This statement proposes a standardised approach to allow comparison between different study populations and devices.
  Neonatology 10/2008; 94(4):320-2. · 2.66 Impact Factor
• Source

  Available from: znanstvenici.hr

  Article: Study of atomic transition self-broadening and shift with the help of a nano-cell

  T Varzhapetyan, A Nersisyan, V Babushkin, D Sarkisyan, S Vdović, G Pichler
  [show abstract] [hide abstract]
  ABSTRACT: We demonstrate experimentally that it is possible to detect and measure the self-broadening rate and frequency shift of the rubidium second principal series atomic transitions at very high atomic vapour densities up to ~1017 cm−3. The experimental procedure includes the usual absorption measurement technique and a sealed-off nano-cell containing Rb vapour operating at high temperatures with a thickness of L = λ/2, where λ is the resonant wavelength (420 nm).
  Journal of Physics B Atomic Molecular and Optical Physics 09/2008; 41(18):185004. · 1.88 Impact Factor
• Article: Forearm and calf tissue oxygenation in term neonates measured with near-infrared spectroscopy.

  G Pichler, J Heinzinger, J Kutschera, H Zotter, W Müller, B Urlesberger
  [show abstract] [hide abstract]
  ABSTRACT: Peripheral tissue oxygenation has been studied with near-infrared spectroscopy (NIRS) on either the forearm or calf with questionable comparability. The aim was to compare forearm and calf tissue oxygenation in healthy term neonates measured with NIRS. Fractional oxygen extraction, tissue oxygenation index, and mixed venous oxygenation were similar in both extremities, whereas oxygen delivery and oxygen consumption of calf tissue were higher.
  The Journal of Physiological Sciences 11/2007; 57(5):317-9. · 1.61 Impact Factor
• Article: RbCs bands observation and interpretation

  R. Beuc, M. Movre, B. Horvatić, M. Čopor, S. Vdović, A. Nevsesyan, T. Varzhapetyan, D. Sarkisyan, G. Pichler
  [show abstract] [hide abstract]
  ABSTRACT: We calculated the approximate form of absorption bands of RbCs molecules in the 450–1000nm wavelength range. The manifold of potential curves for the Hund’s coupling case a was used to predict the absorption spectra assuming constant transition dipole moments, which can serve as a first approximation for the comparison with experimental results and their interpretation. Any substantial departure of an observed spectrum from the predicted one would point to the need of more complex calculations comprising transition-dipole-moment functions and spin–orbit interaction. Comparison with RbCs absorption bands from hot vapor is discussed. The band at 717nm is identified as the 11Σ+→11Π transition (B–X band) and the diffuse band at 563nm as the 11Σ+→31Π transition.
  Applied Physics B 05/2007; 88(1):111-115. · 2.19 Impact Factor
• Article: Do wet diapers induce arousals in sleeping infants?

  H Zotter, B Urlesberger, G Pichler, W Mueller, R Kerbl
  [show abstract] [hide abstract]
  ABSTRACT: To find out whether simulated bladder voiding was able to induce arousals in sleeping infants. Polygraphic recordings were performed in 34 infants and voiding was simulated by administering water into the diaper. Heart rate, respiratory frequency and electroencephalogram frequency did not change significantly during this procedure. Furthermore, simulated voiding was unable to cause an awakening or to induce body movements in sleeping infants. Simulated voiding was unable to induce arousals.
  Acta Paediatrica 04/2007; 96(3):452-3. · 2.07 Impact Factor
• Article: Femtosecond laser pulse train effect on Doppler profile of cesium resonance lines

  N. Vujičić, S. Vdović, D. Aumiler, T. Ban, H. Skenderović, G. Pichler
  [show abstract] [hide abstract]
  ABSTRACT: We present direct observation of the velocity-selective optical pumping of the Cs ground state hyperfine levels induced by the femtosecond (fs) laser oscillator centered at either D2 (6 2S1/2↦6 2P3/2, 852nm) or D1 (6 2S1/2®62^{2}{\rm S}_{1/2}\to6~^{2} P1/2, 894nm) cesium line. We utilized previously developed modified direct frequency comb spectroscopy (DFCS) which uses a fixed frequency comb for the excitation and a weak cw scanning probe laser centered at the 133Cs 6 2S1/2↦6 2P3/2 transition (D2 line) for ground levels population monitoring. The frequency comb excitation changes the usual Doppler absorption profile into a specific periodic, comblike structure. The mechanism of the velocity selective population transfer between the Cs ground state hyperfine levels induced by fs pulse train excitation is verified in a theoretical treatment of the multilevel atomic system subjected to a pulse train resonant field interaction.
  The European Physical Journal D 02/2007; 41(3):447-454. · 1.48 Impact Factor
• Article: Peripheral oxygenation in term neonates.

  G Pichler, K Grossauer, P Klaritsch, J Kutschera, H Zotter, W Müller, B Urlesberger
  [show abstract] [hide abstract]
  ABSTRACT: The aim of this study was to analyse changes in peripheral oxygenation in healthy term neonates within the first week of life with near-infrared spectroscopy and venous occlusion. Oxygen delivery did not change with increasing age. Oxygen consumption and fractional oxygen extraction increased, whereas tissue oxygenation index decreased with increasing age.
  Archives of Disease in Childhood - Fetal and Neonatal Edition 02/2007; 92(1):F51-2. · 3.05 Impact Factor
• Source

  Available from: Robert Beuc

  Article: Photoassociation of cesium atoms into Cs2 3 3Πg state at 543.5 nm

  T. Ban, H. Skenderović, R. Beuc, G. Pichler
  [show abstract] [hide abstract]
  ABSTRACT: We report absorption measurements in pure cesium vapor at high temperatures, when triplet absorption bands in the spectral interval 540–560 nm emerge within the singlet molecular bands which slowly diminish due to efficient thermal dissociation. The absorption bands have been identified as stemming from extrema in the Cs2 3 3Πg-a 3Σu+ difference potential curve. We performed a quasiclassical simulation which agrees well with experimental observation. Since the Cs2 a 3Σu+ state is only weakly bound, the observed absorption bands at 543.5 and 557 nm represent free-bound transitions or the photoassociation process.
  EPL (Europhysics Letters) 01/2007; 48(4):378. · 2.17 Impact Factor
• Article: UV, Visible and IR Spectrum of the Cs High Pressure Lamp

  G Pichler, V Živčec, R Beuc, Ž Mrzljak, T Ban, H Skenderović, K Günther, J Liu
  [show abstract] [hide abstract]
  ABSTRACT: High pressure pulsed discharge with cesium vapor could become a very promising lamp, because of its white light properties. It has considerable losses in the infrared spectral region and negligible contribution in the near UV spectral region. We shall present the results of extensive spectral studies of such a lamp with a special emphasis on the near infrared and near UV portions of emission spectra for a variety of experimental conditions. We shall discuss the origin of atomic emission lines and some peculiar molecular bands, which contribute to the overall emission in these spectral regions.
  Physica Scripta 07/2006; 2003(T105):98. · 1.20 Impact Factor
• Article: Forearm oxygen consumption and forearm blood flow in healthy children and adolescents measured by near infrared spectroscopy.

  G Pichler, B Urlesberger, P Jirak, H Zotter, W Müller
  [show abstract] [hide abstract]
  ABSTRACT: The assessment of forearm oxygen consumption (VO(2)) and forearm blood flow (FBF) by means of near infrared spectroscopy has become widespread in adults, whereas in children and adolescents no data are available. The aim of the present study was to analyze VO(2) and FBF in healthy children and adolescents. In a prospective cohort study, 20 male and 20 female healthy children and adolescents were investigated. The measurements of VO(2) and FBF were performed by means of near infrared spectroscopy in combination with the venous occlusion method. Mean VO(2) was 0.08 +/- 0.04 ml 100 g(-1) min(-1) in male and 0.09 +/- 0.05 ml 100 g(-1) min(-1) in female subjects. Mean FBF was 1.95 +/- 1.25 ml 100 g(-1) min(-1) in male and 1.82 +/- 0.98 ml 100 g(-1) min(-1) in female subjects. No significant difference was found between male and female subjects. A significant negative correlation of VO(2) and FBF to age was observed in both groups. In the present study we were able to show that VO(2) and FBF decreased with increasing age in children and adolescents without significant differences between male and female subjects.
  The Journal of Physiological Sciences 07/2006; 56(3):191-4. · 1.61 Impact Factor
• Article: Mapping of the optical frequency comb to the atom-velocity comb

  T. Ban, D. Aumiler, H. Skenderović, G. Pichler
  [show abstract] [hide abstract]
  ABSTRACT: A mode-locked femtosecond laser is used to physically map the laser frequency comb into the velocity comb of the excited Rb atoms at room temperature. Upon resonant excitation by discrete optical frequencies the velocity distribution of the excited Rb atoms shows comblike structure. Simultaneously, velocity-selective population transfer occurs between ground-state hyperfine levels. Both facts are observed by modified direct frequency comb spectroscopy and verified by a detailed density matrix treatment of the multilevel system in resonant field.
  Phys. Rev. A. 04/2006; 73(4).
• Article: Quasiresonant Excitation of Lithium 2p–4d and 2p–4s Transitions in Li-Cd Vapor Mixture

  S Milošević, D Azinović, I Labazan, G Pichler
  [show abstract] [hide abstract]
  ABSTRACT: We performed quasiresonant laser excitation of Li–Cd vapor mixtures at 460.3 nm (2p–4d) and 497.2 nm (2p–4s). The initial population of the Li(2p) level is caused by three processes: collisional dissociation or photodissociation of the Li2(B1Πu) molecules or energy transfer in Li2(B1Πu) and Li(2s) collisions. The Li(4d,4s) atoms radiatively decay towards Li(3p), from which collisional population transfer to Cd(53PJ) occurs, followed by three-body reactive collisions which produce the LiCd(22Π ) excimer states
  Physica Scripta 03/2006; 62(2-3):137. · 1.20 Impact Factor