Optical spin injection and spin lifetime in Ge heterostructures.

We demonstrate optical orientation in Ge/SiGe quantum wells and study their spin properties. The ultrafast electron transfer from the center of the Brillouin zone to its edge allows us to achieve high spin polarizations and to resolve the spin dynamics of holes and electrons. The circular polarization degree of the direct gap photoluminescence exceeds the theoretical bulk limit, yielding ∼37% and ∼85% for transitions with heavy and light holes states, respectively. The spin lifetime of holes at the top of the valence band is estimated to be ∼0.5 ps and it is governed by transitions between light and heavy hole states. Electrons at the bottom of the conduction band, on the other hand, have a spin lifetime that exceeds 5 ns below 150 K. Theoretical analysis of the spin relaxation indicates that phonon-induced intervalley scattering dictates the spin lifetime of electrons.

Precise control of thermal conductivity at the nanoscale through individual phonon-scattering barriers.

The ability to precisely control the thermal conductivity (kappa) of a material is fundamental in the development of on-chip heat management or energy conversion applications. Nanostructuring permits a marked reduction of kappa of single-crystalline materials, as recently demonstrated for silicon nanowires. However, silicon-based nanostructured materials with extremely low kappa are not limited to nanowires. By engineering a set of individual phonon-scattering nanodot barriers we have accurately tailored the thermal conductivity of a single-crystalline SiGe material in spatially defined regions as short as approximately 15 nm. Single-barrier thermal resistances between 2 and 4 x 10(-9) m(2) K W(-1) were attained, resulting in a room-temperature kappa down to about 0.9 W m(-1) K(-1), in multilayered structures with as little as five barriers. Such low thermal conductivity is compatible with a totally diffuse mismatch model for the barriers, and it is well below the amorphous limit. The results are in agreement with atomistic Green's function simulations.

Collective shape oscillations of SiGe islands on pit-patterned Si(001) substrates: a coherent-growth strategy enabled by self-regulated intermixing.

The shape of coherent SiGe islands epitaxially grown on pit-patterned Si(001) substrates displays very uniform collective oscillations with increasing Ge deposition, transforming cyclically between shallower "dome" and steeper "barn" morphologies. Correspondingly, the average Ge content in the alloyed islands also displays an oscillatory behavior, superimposed on a progressive Si enrichment with increasing size. We show that such a growth mode, remarkably different from the flat-substrate case, allows the islands to keep growing in size while avoiding plastic relaxation.

Coping strategies in intestinal transplantation.

The psychological construct of coping has been studied extensively in other medical populations and has more recently been applied in the field of transplant psychology. Coping can be defined as all abilities used by people to face problematical and stressful situations, as the data in literature describe the experience of transplantation. The purpose of this study was to describe the coping styles used by 25 intestinal transplant recipients. To assess the coping strategies, we used the Italian version of Coping Orientation to Problems Experienced (COPE) by Sica, Novara, Dorz, and Sanavio (1997). The authors divided these strategies into three classes: problem-focused, emotion-focused, and potentially disadaptive strategies. This questionnaire is usually used in a medical setting. Even if the long process of psychological-clinical adaptation required by intestinal transplantation put patients in a passive acceptance of their situation and their incapacity to face it, our patients showed high levels of problem-focused strategies, indicators of positive outcomes for this intervention. Anyway, this is a slow and gradual path that goes with the psychological distress and the need for a peculiar psychological support of problem-focused strategies. The result suggested that assessment of coping strategies should be explored in intestinal transplant to encourage the use of action-oriented methods and discourage those with possible negative effects.

Italian experience in adult clinical intestinal and multivisceral transplantation: 6 years later.

PATIENTS AND METHODS: Between December 2000 and November 2006, 28 isolated intestinal transplants and nine multivisceral transplants (five with liver) from cadaveric donors have been performed for short gut syndrome (n = 15), chronic intestinal pseudo-obstruction (n = 10), Gardner's syndrome (n = 9), radiation enteritis (n = 1), intestinal atresia (n = 1), and massive intestinal angiomatosis (n = 1). Indications for transplantations were: loss of venous access, recurrent sepsis due to central line infection, and/or major electrolyte and fluid imbalance. Liver dysfunction was present in 19 cases. All patients were adults of median age at transplant of 34.7 years and mean weight 59.6 kg. All recipients were on total parenteral nutrition for a mean time of 38.8 months. Mean donor/recipient body weight ratio was 1.1. RESULTS: The mean follow-up was 892 +/- 699 days. Twenty-five patients were alive (67.5%) with 3-year patient survivals of 70% for isolated intestinal transplantations and 41% for the multivisceral transplantations (P = .01). The mortality rate was 32.5% with losses due to sepsis (63%) or rejection. Our 3-year graft survival rates were 70% for isolated intestinal transplantations and 41% for multivisceral transplantations (P = .02); graftectomy rate was 16%. These were 88% of grafts working properly with patients on regular diet with no need for parenteral nutrition. DISCUSSION AND CONCLUSIONS: Induction therapy has reduced the doses of postoperative immunosuppressive agents, especially in the first period, lowering the risk of renal failure and sepsis, mucosal surveillance protocol for early detection of rejection dramatically reduced the number of severe acute chronic rejections.

[Chronic fatigue syndrome: from misunderstood illness to cause of job fitness management problem and of work total disability in a physiotherapist. Case report]. / Sindrome da stanchezza cronica: da malattia incompresa a causa di inidoneità lavorativa specifica e di inabilità totale al lavoro, in lavoratrice fisioterapista. Case report.

The aim of this paper is to report the case of a Physiotherapist working in a big hospital, affected by Chronic Fatigue Syndrome (CFS). After the diagnosis, made in an High Specialized Center, the Occupational Health Physician, with the cooperation of the Nursing Managing Direction, the Chief of the Department of Rehabilitation and the Physiotherapists Coordinator, had to cope with the job fitness management. Afterwards the patient, in accordance with the Physician of a Trade Union Medical Office and the Occupational Health Physician, tried to obtain the disability pension, that at the end was given by the Medical Commission of the ASL.

Angiosarcoma of the heart: structural and ultrastructural study.

BACKGROUND: Primary cardiac tumours are rare. Nearly 70% of primary cardiac tumours are benign, the majority of which are represented by myxomas. The most frequent primary cardiac neoplasm is the angiosarcoma that represents 31% of primary cardiac malignant. We report a particular clinical case of cardiac angiosarcoma, its light and transmission electron microscopic aspects and a review of the recent literature. METHODS: A 52 years old man died for a severe right ventricle filling deficit caused by an intracavitary tumour originated from the right atrial anterolateral wall. The fragments obtained from autoptic tumoral cardiac tissue were processed for light and electron microscopy. The section were stained with haematoxilineosin, Masson trichromic and Gomori method. An immunohistochemical study for vimentin, Factor VIII related antigen and peroxidase-conjugated lectin from Ulex Europaeus was also performed using the unlabed peroxidase-antiperoxidase method. RESULTS: The hematoxylin-eosin staining showed that the tumoral mass was composed by a well-differentiated histotype characterized by numerous vascular areas in which neoplastic cells were loosely and irregularly arranged to form incomplete vessels or anastomized blood-filled vascular channels. On the other hand, some less-differentiated solid areas were present and irregularly surrounded the differentiated vascular areas. Results of Ulex Europeaeus Agglutinin I labelling were positive in both solid and vascular areas of the tumour although the positive reaction was less evident in the solid zones Factor VIII related antigen positive cells were less numerous and mainly found in vascular areas. The observation by electron microscopy showed the lack of evident pinocytotic vesicles, the presence of thin and delicate cytoplasmatic processes, Weibel-Palade bodies, and also the disarrangement of the extracellular fibrous matrix. CONCLUSION: The light microscopy observation and immunohistochemical study underscore that is not easy to obtain information about the level of differentiation of this tumour. The presence of blood-filled lumina and the identification of typical markers of endothelial cells seems to indicate a well-differentiated nature. However, the ultrastructural findings seem to indicate a less differentiated nature.

[The role and limitations of litholytic therapy of cholesterin cholecystolithiasis. Results in 86 cases treated with chenic acid]. / Ruolo e limiti della terapia litolitica della colecistolitiasi colesterinica. Risultati di 86 casi trattati con acido chenico.

86 carefully selected patients with cholesterinic cholecystic lithiasis were submitted to litholytic treatment with chenodesoxycholic acid at a dose of 15 mg per kg of body weight as part of a multidisciplinary therapeutic approach to biliary lithiasis. Follow up of these patients up to 24 months showed the positive action of the drug on dyspeptic pain symptomatology, the absence of significant side effects, and the absence of hepatotoxic effects of chenic acid at therapeutic doses, as well as its effectiveness with respect to total or partial litholysis in 78% of patients. These data confirm the positive role of litholytic treatment as an alternative to cholecystectomy in highly selected patients treated at specialist centres.

Assessing the composition of hetero-epitaxial islands via morphological analysis: an analytical model matching GeSi/Si(001) data.

A simple, but still three-dimensional, model describing the morphological stability of realistic SiGe islands on Si(001) is presented. The experimental evolution toward steeper islands with volume can be predicted for any average composition. Despite the use of elastic theory for stress relaxation under the assumption of a uniform SiGe distribution, and of a common mean surface energy of the faceted islands, the model seems to capture the essence of the energetic balance determining the morphological evolution with volume, with no fitting parameters. This is suggested by close comparison with molecular beam epitaxy data at three different temperatures (i.e. compositions). The good agreement also allows for interpreting the minor scattering of experimental data with temperature and provides a reliable tool for extracting the average Ge content from standard atomic force microscopy analysis.

Alloying and Strain Relaxation in SiGe Islands Grown on Pit-Patterned Si(001) Substrates Probed by Nanotomography.

The three-dimensional composition profiles of individual SiGe/Si(001) islands grown on planar and pit-patterned substrates are determined by atomic force microscopy (AFM)-based nanotomography. The observed differences in lateral and vertical composition gradients are correlated with the island morphology. This approach allowed us to employ AFM to simultaneously gather information on the composition and strain of SiGe islands. Our quantitative analysis demonstrates that for islands with a fixed aspect ratio, a modified geometry of the substrate provides an enhancement of the relaxation, finally leading to a reduced intermixing.

[Ultrasonographic findings in Osgood-Schlatter disease]. / Aspetti ultrasonografici della malattia di Osgood-Schlatter.

The Osgood-Schlatter disease affects the patellar tendon in its attachment to the tibial tuberosity. It is quite frequent in adolescents, especially in young males practising sports. Its diagnosis is mainly clinical. The findings of tenderness and focal swelling of the tibial tuberosity are typical of this condition. The Osgood-Schlatter disease can damage bone, cartilage, tendon and serous bursa. US yields complete information on the involvement of these structures. High-resolution US of the knee was performed on 70 patients with clinically suspected Osgood-Schlatter disease. More or less apparent cartilage swelling was demonstrated in 100% of our patients, tibial tuberosity fragmentation in 75%, diffuse thickening of the patellar tendon, at times inhomogeneous, in 22% and finally bursitis of the infrapatellar bursa was demonstrated in 17% of our patients. US provides complete information on the involvement of the tibial tuberosity and of the surrounding soft tissues, thus proving to be a simple and reliable method to diagnose the Osgood-Schlatter disease. Moreover, US is suitable for the periodical follow-up of disease course.

Congenital hip dysplasia treated by the Salter osteotomy. Long-term review of 18 patients.

Between 1965 and 1974 at the Orthopaedic Clinic of the University of Perugia, 20 osteotomies of the innominate bone were performed on 18 patients aged between 18 months and 10 years. All the patients were followed up for 10 to 19 years (average 15 years) after operation. The results were evaluated both clinically and radiographically (according to the Severin and MacFarland methods). The data were later submitted to computer analysis, using a semiautomatic aquisition programme which allowed for evaluation of the geometry of the hip. The most important parameters for evaluation of the results were the Wiberg CE angle, the acetabular angle, the minimum joint space, and the horizontal component of the resultant force. Clinically and radiographically there was an 80% success rate according to Severin's method of evaluation. There was also good correlation with the computerized analysis. Biomechanically, there was almost normal recovery of the load distribution. The clinical, radiographic and biomechanical parameters worsened slightly with age, particularly during puberty.