InP monolithically integrated coherent transmitter.

A novel InP monolithically integrated coherent transmitter has been designed, fabricated and tested. The photonic integrated circuit consists of a distributed Bragg reflector laser and a modified nested Mach-Zehnder modulator having tunable input power splitters. Back-to-back coherent transmission for PDM-QPSK signals is reported up to 10 Gbaud (40 Gb/s) using the integrated laser and up to 32Gbaud (128 Gb/s) using an external low phase noise laser.

Sub-Nyquist field trial using time frequency packed DP-QPSK super-channel within fixed ITU-T grid.

Sub-Nyquist time frequency packing technique was demonstrated for the first time in a super-channel field trial transmission over long-haul distances. The technique allows a limited spectral occupancy even with low order modulation formats. The transmission was successfully performed on a deployed Australian link between Sydney and Melbourne which included 995 km of uncompensated SMF with coexistent traffic. 40 and 100 Gb/s co-propagating channels were transmitted together with the super-channel in a 50 GHz ITU-T grid without additional penalty. The super-channel consisted of eight sub-channels with low-level modulation format, i.e. DP-QPSK, guaranteeing better OSNR robustness and reduced complexity with respect to higher order formats. At the receiver side, coherent detection was used together with iterative maximum-a-posteriori (MAP) detection and decoding. A 975 Gb/s DP-QPSK super-channel was successfully transmitted between Sydney and Melbourne within four 50GHz WSS channels (200 GHz). A maximum potential SE of 5.58 bit/s/Hz was achieved with an OSNR = 15.8 dB, comparable to the OSNR of the installed 100 Gb/s channels. The system reliability was proven through long term measurements. In addition, by closing the link in a loop back configuration, a potential SE∙d product of 9254 bit/s/Hz·km was achieved.

Near infrared image processing to quantitate and visualize oxygen saturation during vascular occlusion.

The assessment of microcirculation spatial heterogeneity on the hand skin is the main objective of this work. Near-infrared spectroscopy based 2D imaging is a non-invasive technique for the assessment of tissue oxygenation. The haemoglobin oxygen saturation images were acquired by a dedicated camera (Kent Imaging) during baseline, ischaemia (brachial artery cuff occlusion) and reperfusion. Acquired images underwent a preliminary restoration process aimed at removing degradations occurring during signal capturing. Then, wavelet transform based multiscale analysis was applied to identify edges by detecting local maxima and minima across successive scales. Segmentation of test areas during different conditions was obtained by thresholding-based region growing approach. The method identifies the differences in microcirculatory control of blood flow in different regions of the hand skin. The obtained results demonstrate the potential use of NIRS images for the clinical evaluation of skin disease and microcirculatory dysfunction.

Pemberton's pericapsular osteotomy for the treatment of acetabular dysplasia.

We present the results of 80 Pemberton procedures carried out between 1977 and 1990. The patient age at the time of operation ranged between 2 and 12 years, and follow-up was between 1 and 15 years. Before Pemberton's operation, conservative treatment, closed and open reduction, and derotation femoral osteotomy were used. Pemberton's operation was combined with intertrochanteric femoral osteotomy in 30 cases. The mean values of the acetabular and center edge angle of Wiberg showed postoperative improvement of 19 and 17 degrees, respectively; whereas at follow-up, improvement was 20 and 23 degrees, respectively. Radiologically, 79% of the cases met Severin's classification grade I-II criteria. Clinically, 81% were classified as excellent and good. The results were closely correlated with ischemic necrosis due to preoperative treatment. Only patients belonging to groups II-IV of Kalamchi and MacEwen, plus one patient operated on at relatively old age (12 years), were found radiologically to be in Severin's groups III and IV. The results among patients operated on before age 7 were more favorable than those of patients operated on at an older age.

[Indication for Chiari's pelvic osteotomy]. / Die Indikation der Beckenosteotomie nach Chiari.

The results of 61 Chiari's pelvic osteotomies carried out during a 10 years period are reported. Present role of the operation in the correction of acetabular dysplasia in comparison to Pemberton's acetabuloplasty, to triple pelvic osteotomies and to the prosthetic replacement of the hip joint is discussed. In conclusion the operation is still indicated in special cases. Depending on the age of the patients pain can be observed already after 3-5 years however a great part of the patients is completely free of complaints even 10 years postoperatively.

[Results of combined surgical operations in the management of congenital hip dislocation]. / Kombinált mütétek eredményei a veleszületett csípöficam kezelésében.

The results of 51 different combined operations for the treatment of CDH after the age of two years performed between 1980 and 1989 are presented. The age of the patients at the time of the operation ranged from 2 to 12 (mean 4.5 years. Follow-up was 2-12 (meean 6) years. Preoperatively 19 hips were untreated. Primary surgery included reduction alone in 6 cases, together with femoral osteotomy in 28 cases, reduction combined with Pemberton's operation in 1, and reduction supplemented by both correction techniques in 16 cases. Secondary acetabular correction was later necessary only in 14 cases (27%), thus in 63% of all cases. Radiologycally, the results were of Severin's grade I and II in 64% of the whole series, but in 88% in the 2-3-years-old group. The results in the different surgical groups correlated primarily with the incidence of avascular necrosis and not with the extent of surgery.

Efficacy of prevention of thromboembolic complications with LMW-heparin in experiment.

The authors used an antithrombotic agent (Nadroparin Calcium) with anti-Xa effect in their experiments to prevent thromboembolic complications in the model of endoprosthetic replacement of the hip joint in mongrel dogs. 10 experimental animals (Group I.) were given doses of 100 A Xa ICU/kg/bwt of Nadroparin Calcium subcutaneously 4 hours prior to the operation and also once a day until the 3rd postoperative day; between the 4th and 10th postoperative days doses of 150 A Xa ICU/kg/bwt Nadroparin Calcium were given. The 10 control animals (Group II.) did not receive anticoagulant treatment. In both groups platelet count, activated partial thromboplastin times (APTT), prothrombin and fibrinogen levels as well as activated factor X inhibition (F Xa) were measured prior to surgery and also until the 14th postoperative day. No changes in APTT and prothrombin levels were detected during the experiment, however platelet count and fibrinogen levels as well as the extent of F Xa inhibition showed significant and different changes in groups I. and II. The Group I. which had received thromboembolic prophylaxis did not develop deep venous thrombosis or pulmonary embolism, but the control group did. Based on their investigations, the authors concluded that they had been able to achieve F Xa inhibition by giving the above mentioned doses of Nadroparin Calcium which was enough to prevent thromboembolic complications in their model experiment of implanting hip endoprosthesis.