Sialadenitis as chickenpox complication in a 6-year-old girl.

Chickenpox is considered as a mild disease, but sometimes it is associated with complications. Among them sialadenitis is mentioned sporadically. We describe a case of the 6-year-old girl suffering from complicated chickenpox. On the basis of clinical data and ultrasound image we diagnosed in her inflammation of both submandibular glands. Moreover, the ultrasound image suggested possibility of an inflammation developing in the left parotid gland.

Physico-chemical investigation of endodontic sealers exposed to simulated intracanal heat application: epoxy resins and zinc oxide-eugenols.

AIM: To gain information in a laboratory setting about the effect of thermal treatment of epoxy resin-based and zinc oxide-eugenol-based sealers. METHODOLOGY: AH Plus and Pulp Canal Sealer (PCS) were exposed to thermal treatment at 37, 47, 57, 67, 77, 87 and 97 °C for 30 s. According to clinically relevant considerations, intracanal sealer temperature is likely not to exceed 60 °C during warm vertical root canal filling. Heat application is recommended for less than 30 s during continuous wave technique, but might exceed this threshold in complex cases. Furthermore, heat treatment at 97 °C was performed for 60 and 180 s to simulate inappropriate implementation of warm vertical filling techniques. Specimens were heated inside 2-mL plastic tubes in a thermo-controlled water bath until the temperatures were reached and kept at this temperature for the determined period of time. Afterwards, specimens were cooled to body temperature and physical properties (setting time, flow, film thickness according to ISO 6876) were assessed. Chemical properties (Fourier transformed infrared spectroscopy) were assessed after complete setting of the specimens in an incubator at 37 °C and 100% humidity. Statistical analysis of physical properties was performed using Kruskal-Wallis test (P = 0.05). RESULTS: The setting time of AH Plus and PCS decreased when temperature and duration of heat application increased. Whilst the setting time of AH Plus decreased from 622 min at 20 °C (for 30 s) to 381 min at 97 °C (for 180 s; P < 0.05), heat treatment of PCS at 97 °C for 180 s led to an immediate setting of the material. From 20 °C (for 30 s) to 97 °C (for 30 s), the setting time of PCS decreased from 80.1 to 41.0 h (P < 0.05). Film thickness and flow were not relevantly influenced by thermal treatment except for PCS at 97 °C for 180 s. FT-IR spectroscopy did not reveal any chemical changes of either sealer after thermal treatment. CONCLUSIONS: Thermal treatment simulating clinically relevant temperature levels and heating times did not lead to any substantial physical or chemical changes at all temperature levels when heating did not exceed 60 s. AH Plus and Pulp Canal Sealer can be considered suitable for warm root filling techniques.

Modelling the fracture-healing process as a moving-interface problem using an interface-capturing approach.

We present a novel numerical model of the fracture-healing process using interface-capturing techniques, a well-known approach from fields like fluid dynamics, to describe tissue growth. One advantage of this method is its direct connection to experimentally observable parameters, including tissue-growth velocities. In our model, osteogenesis, chondrogenesis and revascularisation are triggered by mechanical stimuli via mechano-transduction based on previously established hypothesis of Claes and Heigele. After experimentally verifying the convergence of the numerical method, we compare the predictions of our model with those of the already established Ulm bone-healing model, which serves as a benchmark, and corroborate our results with existing animal experiments. We demonstrate that the new model can predict the history of the interfragmentary movement and forecast a tissue evolution that appears similar to the experimental results. Furthermore, we compare the relative tissue concentration in the healing domain with outcomes of animal experiments. Finally, we discuss the possible application of the model to new fields, where numerical simulations could also prove beneficial.

Atomic resolution elemental mapping using energy-filtered imaging scanning transmission electron microscopy with chromatic aberration correction.

This paper addresses a novel approach to atomic resolution elemental mapping, demonstrating a method that produces elemental maps with a similar resolution to the established method of electron energy-loss spectroscopy in scanning transmission electron microscopy. Dubbed energy-filtered imaging scanning transmission electron microscopy (EFISTEM) this mode of imaging is, by the quantum mechanical principle of reciprocity, equivalent to tilting the probe in energy-filtered transmission electron microscopy (EFTEM) through a cone and incoherently averaging the results. In this paper we present a proof-of-principle EFISTEM experimental study on strontium titanate. The present approach, made possible by chromatic aberration correction, has the advantage that it provides elemental maps which are immune to spatial incoherence in the electron source, coherent aberrations in the probe-forming lens and probe jitter. The veracity of the experiment is supported by quantum mechanical image simulations, which provide an insight into the image-forming process. Elemental maps obtained in EFTEM suffer from the effect known as preservation of elastic contrast, which, for example, can lead to a given atomic species appearing to be in atomic columns where it is not to be found. EFISTEM very substantially reduces the preservation of elastic contrast and yields images which show stability of contrast with changing thickness. The experimental application is demonstrated in a proof-of-principle study on strontium titanate.

Canal cleanliness using different irrigation activation systems: a SEM evaluation.

OBJECTIVES: The purpose of this study was to assess the efficacy of different final irrigation activation methods in removing debris and smear layer in the apical, middle, and coronal portion of straight root canals. MATERIAL AND METHODS: Straight root canals of 58 freshly extracted mandibular premolars were used. Root canals were prepared to size 40.06. Irrigation was performed using 3% sodium hypochlorite. Samples were divided into four equal groups (n = 12) according to the irrigation activation techniques: (A) manual irrigation (MI), (B) EndoActivator (EA) (Dentsply Maillefer, Ballaigues, Switzerland), (C) sonic activation EDDY (EDDY; VDW, Munich, Germany), and (D) passive ultrasonic irrigation (PUI). Ten teeth served as negative controls. Roots were split longitudinally, and the canal walls were subjected to scanning electron microscopy. The presence of debris and smear layer at coronal, middle, and apical levels were evaluated using a 5-point scoring system and statistically analyzed using Kruskal-Wallis and chi-square tests. RESULTS: Canal cleanliness decreased from coronal to apical (P = 0.035). Significantly more debris was removed with EA, EDDY, and PUI compared to MI (P < 0.001; total values), but no differences were observed in the different portions of the root canals (P > 0.05). Smear layer removal with PUI, EA, and EDDY was not significantly different (P > 0.05), but only EDDY and PUI were superior to MI (P < 0.01). CONCLUSION: All activation methods created nearly debris-free canal walls and were superior compared to manual irrigation (P < 0.001). EDDY and PUI also showed significantly better smear layer scores compared to manual irrigation. CLINICAL RELEVANCE: The sonic activation system EDDY performed equally as well as PUI, and both methods were significantly superior compared with manual irrigation in straight root canals with regard to debris and smear layer removal.

Reply to L.M. Brown et al. "Brief history of the Cambridge STEM aberration correction project and its progeny" in Ultramicroscopy 157, 88 (2015).

We comment on a Short Communication recently published in Ultramicroscopy in which Brown et al. criticize our description of the time sequence of events in the development of aberration correction systems in electron optics during the 1990s put forward in the introduction to the Ultramicroscopy April 2015 Special Issue. We present an analysis of the published literature furnishing evidence that our description is correct.

Determination of the 3D shape of a nanoscale crystal with atomic resolution from a single image.

Although the overall atomic structure of a nanoscale crystal is in principle accessible by modern transmission electron microscopy, the precise determination of its surface structure is an intricate problem. Here, we show that aberration-corrected transmission electron microscopy, combined with dedicated numerical evaluation procedures, allows the three-dimensional shape of a thin MgO crystal to be determined from only one single high-resolution image. The sensitivity of the reconstruction procedure is not only sufficient to reveal the surface morphology of the crystal with atomic resolution, but also to detect the presence of adsorbed impurity atoms. The single-image approach that we introduce offers important advantages for three-dimensional studies of radiation-sensitive crystals.

Achromatic elemental mapping beyond the nanoscale in the transmission electron microscope.

Newly developed achromatic electron optics allows the use of wide energy windows and makes feasible energy-filtered transmission electron microscopy (EFTEM) at atomic resolution. In this Letter we present EFTEM images formed using electrons that have undergone a silicon L(2,3) core-shell energy loss, exhibiting a resolution in EFTEM of 1.35 Å. This permits elemental mapping beyond the nanoscale provided that quantum mechanical calculations from first principles are done in tandem with the experiment to understand the physical information encoded in the images.

[Bone healing capacity in patients undergoing total hip arthroplasty]. / Schopnost kostní reparace u pacientu podstupujících implantaci TEP kycelního kloubu.

PURPOSE OF THE STUDY: To identify some characteristics of bone repair capacity in elderly patients who undergo total hip arthroplasty, which requires good healing ability of bone for implant osteointegration and bone defect repair, particularly if revision arthroplasty is necessary. MATERIAL AND METHODS: In a group of 27 patients (mean age, 70 ± 7 years; range, 60 to 81 years) a coincidence of osteoarthritis and osteopenia/ osteoporosis was assessed, and mesenchymal stem cells (MSC) were isolated and their numbers, viability and proliferative capacity were evaluated. The MSC populations were examined for their behaviour on bone tissue scaffolds used in orthopaedic surgery for treatment of bone lesions. Each patient underwent bone densitometry examination before total hip arthroplasty. Bone marrow was harvested intra-operatively from the trochanteric region of the femur. From a portion of bone marrow, MSCs were isolated and cultured, and a mononuclear cell concentrate was obtained. Either whole bone marrow or a mononuclear cell concentrate was applied to selected matrices (allograft, demineralised bone matrix, porous beta-tricalcium phosphate (-TCP), pressed hydroxyapatite or calcium sulphate). The production of new collagen and extracellular mineralized matrix were first assessed in expansion medium and, when the production was low, differentiation medium was used. RESULTS: A coincidence of osteoarthritis and osteopenia/osteoporosis was found in 50% of the patients. All were women with a low body mass index and had been post-menopausal for an average of 23 years. The isolated MSCs contained a high percentage of viable cells (mean, 95%). The mesenchymal cells of patients with osteopenia, as compared with those having normal bone density, showed markedly lower numbers of fibroblastic colony forming units (CFU-F) per ml and had a lower proliferative capacity because the population doubling time during the first four passages was much longer. Of the scaffolds tested, allografts showed the most marked collagen and extracellular mineralized matrix production in expansion medium with either whole bone marrow or a monocyte concentrate; porous -TCP was the best of bone graft substitutes in collagen and extracellular mineralized matrix production by both whole bone marrow and a monocyte concentrate, but this was only in differential medium. DISCUSSION: The coincidence of ostearthritis with osteopenia/osteoporosis was found in a higher number of our patients than is reported in the literature. Also, a lower MSC proliferative capacity and a low number of CFU-F/ml in the patients with low bone density were interesting findings. Better bone regeneration would generally be achieved with higher MSC numbers and the use of growth factors for stimulation of osteoinduction and angiogenesis. Bone marrow harvesting for MSC isolation, cultivation and subsequent transplantation is currently feasible only in an experiment. A bone marrow aspirate can be applied, but it may not provide a sufficient number of MSCs. In addition to autologous bone grafts, the best collagen production was on allografts. In bone graft substitutes, the porous structure played an important role because on a non-porous material (calcium sulphate) the formation of collagen was very low. There was no difference in collagen and extracellular mineralized matrix production between whole bone marrow and monocyte concentrates. CONCLUSIONS: Elderly patients have reduced bone healing capacity also because of osteopenia/osteoporosis that occurs more often than it is generally diagnosed, including its coincidence with osteoarthritis. The mesenchymal stem cells isolated from osteopenic bone give a lower number of CFU-F/ml and have a lower proliferative capacity. Of the matrices for new bone formation, allografts showed the best results because collagen was produced already in expansion medium. Of the graft substitutes, porous -TCP was the best, but with collagen production in differential medium. The use of bone marrow aspirate is currently a method of choice in order to increase MSC numbers at the site of bone healing. The use of growth factors is an expensive treatment. To achieve the goal of reliable promotion of osteogenesis with cultured MSC transplantation and use of composite materials with pro-osteogenic and pro-angiogenic factors will still require many experimental and clinical studies.

Our eight-year experience with breast reconstruction using abdominal advancement flap (207 reconstructions).

There are many possibilities for breast reconstruction after mastectomy. The use of abdominal advancement flap in combination with silicone implant is among the less commonly used methods, although it is simple, fast and leads to excellent results. We started to use this technique at our department eight years ago. Since then we have performed 207 breast reconstructions using abdominal advancement flap in combination with silicone implants. We performed follow-up checks on the patients for between one and six years.

[Valgus high tibial osteotomy - long-term results]. / Valgizacní osteotomie proximální tibie - dlouhodobé výsledky.

PURPOSE OF THE STUDY: The aim of the study was to evaluate the long-term results in a group of patients treated by proximal tibial valgus osteotomy. MATERIAL: A group of 92 high tibial osteotomies performed in the 1985/1994 period were evaluated. All were indicated for primary osteoarthritis. Closing wedge osteotomy was the technique used. Staple-fixed osteotomy was immobilised in a plaster cast for 6 weeks in 44 cases. Osteotomy fixed with a plate in 35 or with a cerclage in 13 cases was immobilised for two weeks. METHODS: Recurrent intensive pain and walking problems were regarded as a termination of the favourable effect of osteotomy. This was evaluated by the Kaplan-Meier survival analysis. The tibio-femoral angle 5 to 10 degrees of valgus was considered as an optimal deformity correction. The results were compared in relation to complications, correction, duration of immobilisation and patient age. RESULTS: The mean age of the patients was 59.8 ± 8.7 years (range, 42 to 78). During surgery, medial unicompartmental arthritis, grade II or higher, was recorded in 59 patients (64.1%) and multicompartmental knee arthritis was found in 66 patients (71.7%). The absence of noticeable problems was reported by 80.4% of the patients at 10 years and by 30.4 % at 15 years after osteotomy. Surgery decreased the range of motion from 100 ± 6.9 to 94.5 ± 17.7 degrees flexion (p = 0.04). Poor correction and post-operative complications were found in 21 patients (22.8 %) who also experienced significantly worse outcomes (p = 0.003). Good results after 10 and 15 years were reported by 47.6% and 14.3% of the patients, respectively. Of 71 patients (77.2%) who had good correction and surgery without complications, the osteotomy showed a good effect in 90.1% at 10 post-operative years and in 35.2% at 15 years. A longer immobilisation resulted in significantly worse results (p = 0.04) and a restricted range of motion (p = 0.02). The patients younger than 60 years achieved better results than the elderly patients (p = 0.38), but the difference was not significant. DISCUSSION: Good results were recorded up to 10 years after osteotomy, although some patients had had worse arthritis than recommended for this procedure. Inadequate correction and complications deteriorated the effect of osteotomy. With the opening wedge technique it is easier to achieve good correction, and stable fixation allows for active physical therapy. Better long-lasting results are achieved with total knee arthroplasty (TKA). However, in young active adults TKA can fail prematurely. Osteotomy can postpone the necessity of this implantation. If TKA is performed after osteotomy, functional outcomes are similar to those after primary implantation. CONCLUSIONS: Corrective osteotomy is an effective method in patients below 60 years who have an early-stage osteoarthritis of the knee with axial mal-alignment. If the tibio-femoral angle is over-corrected to more than 10 degrees valgus, patelo-femoral pain will ensue. Post-operative active physical therapy is necessary. After bone healing, implants must be removed. Corrective osteotomy has not been overcome by the development of joint replacement techniques, but both methods are complementary in the treatment of osteoarthritis.

[Venous thromboembolism prophylaxis after total hip arthroplasty]. / Prevence tromboembolické nemoci po implantaci totální endoprotézy kycelního kloubu.

PURPOSE OF THE STUDY The authors compare the frequency of thromboembolic disease in the patients receiving prophylactic therapy for 10 days with that in the patients having a prolonged course of preventive treatment recommended for up to 35 days after total hip arthroplasty (THA). MATERIAL The group first evaluated comprised patients undergoing total hip replacement in 2005 and 2006 when enoxaparin was administered for 10 days after surgery. Patients with revision THA were not included. The other group included patients operated on in 2008 who received preventive treatment for 35 post-operative days either with enoxaparin for the whole time, or with enoxaparin for 10 days of hospital stay and then warfarin up to the 35th day after surgery. Patients under going revision THA and those taking other prophylactic agents were not evaluated. METHODS The evaluation of the 2005/6 group included retrospective reviews of medical records, questionnaires sent to the patients and information received from their general practitioners. The 2008 group assessment was based on the information obtained at the patient's follow-up visit at 3 months and completed with data from the questionnaires and medical notes. We focused on the records of distal or proximal deep vein thrombosis in lower extremities and of pulmonary embolism including cases with a fatal outcome. Complications associated with pharmacological prevention were also recorded. RESULTS In the 2005/6 group including 478 patients with an average age of 67.2 years, 23 (4.8 %) patients developed thrombo- embolic disease within 3 months of surgery, six patients had pulmonary embolism of which two of them died. The thromboembolic complication developed at a median of 30.5 post-operative days, i.e., after patient discharge from hospital. In the 2008 group comprising 289 patients with an average age of 63.8 years, three patients (1 %) developed thromboembolic disease within 3 months of surgery. Of them, one woman had deep vein thrombosis in relation to a high factor VIII level; and one developed pulmonary embolism with no fatal outcome. Only the minority of patients (6.9 %) continued enoxaparin therapy, the majority (93.1 %) preferred conversion to warfarin after discharge from hospital. Of the total number of 289 patients evaluated, complications associated with prophylactic treatment were recorded in 52 patients (18 %), name- ly, in 35 patients (12.1 %) it was difficult to establish the correct dosage of warfarin, in 13 patients (4.5 %) warfarin caused minor bleeding or dyspepsia and in 4 patients (1.4 %) major bleeding was recorded. DISCUSSION In our study the patients receiving a 10-day prophylactic therapy showed a slightly higher occurrence of thromboembolic disease within 3 months of THA surgery (4.8 %) than the patients reported by Eikelboom et al. (4.3 %). The results of prolonged prophylactic treatment for at least 35 days were similar, thromboembolic disease was found in 1 % of the patients. The development of thromboembolic event was recorded in our study at a median of 30.5 post-operative days, as compared with a median of 17 days in the study by Liebermann et al. In both studies, most of the thromboembolic complications developed after the patients had been discharged from hospital. The majority of patients chose warfarin for prolonged preventive treatment. There was a high complication rate (18 %) due to not finding the correct warfarin dosage or because of its overdose CONCLUSIONS Patients undergoing THA are at high risk of developing deep vein thrombosis. The risk can be markedly reduced by prolonged pharmacological ophylaxis It is recommended that the use of warfarin for this prolonged therapy should be care- fully considered, because its optimal dose is difficult to establish and its overdose may cause serious complications.

The signalling role of action potential depolarization in insulin secretion: metabolism-dependent dissociation between action potential increase and secretion increase by TEA.

The K(+) channel blocker, TEA is known to increase action potential amplitude and insulin secretion of mouse beta-cells when added to a nutrient secretagogue. In the presence of a maximally effective sulfonylurea concentration (2.7 microM glipizide) the nutrient secretagogue alpha-ketoisocaproic acid (KIC, 10mM) strongly increased insulin secretion (about elevenfold). Instead of enhancing the effect of KIC, TEA reduced the KIC-induced secretion by more than 50%. Also, the secretion rate produced by 2.7 microM glipizide alone was significantly reduced by TEA. In contrast, TEA enhanced the insulinotropic effect of glipizide when a basal glucose concentration (5mM) was present. In the presence as well as in the absence of glucose glipizide produced a plateau depolarization with superimposed action potentials. Under both conditions, TEA increased the glipizide-induced action potential amplitude and further elevated the cytosolic free calcium concentration ([Ca(2+)](i)) with an oscillatory characteristic. These effects depended on the activity of L-type Ca(2+) channels, even though the effect of TEA differed from that of 1 microM of the Ca(2+) channel opener, Bay K8644, which primarily increased action potential duration. TEA did not negatively affect parameters of beta-cell energy metabolism (NAD(P)H fluorescence and ATP/ADP ratio), rather, it slightly increased NAD(P)H fluorescence. Apparently, TEA inhibits insulin secretion in the absence of glucose in spite of a persistent ability to block K(+) ion conductance. Thus, the signalling role of action potential depolarization in insulin secretion may require reconsideration and ion conductance-independent actions of K(+) channels may be involved in this paradox effect of TEA.

Effect of a single dislocation in a heterostructure layer on the local polarization of a ferroelectric layer.

We study, on an atomic scale, the influence of a single dislocation in a SrTiO3 sublayer on the local ferroelectric polarization of the neighboring ferroelectric PbZr0.2Ti0.8O3 (PZT) sublayer in an epitaxial SrTiO3/PbZr0.2Ti0.8O3/SrTiO3 three-layer heterostructure. The strain field of the dislocation in the SrTiO3 layer propagates across the interface into the PZT layer and leads to a strong variation of the c-lattice parameter of the PZT layer. Accompanying a strong reduction of the c-lattice parameter, the off-center displacements of the Zr/Ti atoms away from the center of the oxygen octahedra are also strongly decreased, resulting in a decrease of the local spontaneous polarization by up to 48%.

Manganese adlayers on i-Al-Pd-Mn quasicrystal: growth and electronic structure.

Pseudomorphic growth of thin elemental metal films is often observed on a variety of crystalline solids. On quasicrystalline surfaces with their complex structure and the absence of translational periodicity, the situation is different since elemental metals do not exhibit quasicrystalline order, and hence the specific interaction between overlayer and substrate is decisive. Here we study the growth of manganese films on an icosahedral i-Al-Pd-Mn alloy with a view to establishing the growth mode and electronic structure. Although we observe an exponential intensity variation of the adlayer and substrate related x-ray photoemission spectroscopy (XPS) peaks, low energy electron diffraction (LEED) shows that Mn adlayers do not exhibit quasicrystallinity. The detailed structure of the Mn 2p core level line reveals considerable electronic structure differences between the quasicrystalline and elemental metal environment. Evidence of a substantial local magnetic moment on the Mn atoms in the overlayer (about 2.8  µ(B)) is obtained from the Mn 3s exchange splitting.

[Restricted motion after total knee arthroplasty]. / Omezení hybnosti kolenního kloubu po implantaci totální endoprotézy.

PURPOSE OF THE STUDY: The aim of the study was to ascertain what proportion of patients undergoing total knee arthroplasty (TKA) complain of restricted knee joint motion, and to investigate options for improvement of this situation. MATERIAL: Our evaluation included a group of 796 patients treated with TKA at our department in the period from January 1, 1990, to December 31, 2004. In all cases, a condylar implant with preservation of the posterior cruciate ligaments was used. METHODS: In addition to medical history, the range of motion, knee joint malalignment and radiological findings were assessed before surgery. After THA, the type of implant and complications, if any, were recorded, and improvement in joint motion was followed up. Based on the results of Kim et al., flexion contracture equal to or higher than 15 degrees and/or flexion less than 75 degrees were made the criteria of stiffness after THA. Patients with restricted THA motion who had aseptic or septic implant loosening were not included. RESULTS: Of the 796 evaluated patients, 32 (4.14 %) showed restricted motion after total knee arthroplasty, as assessed by the established criteria. In 16 patients, stiffness defined by these criteria had existed before surgery, and three patients showed an excessive production of adhesions and heterotopic ossifications. In three patients, the implantation procedure resulted in an elevated level of the original joint line and subsequent development of patella infera and increased tension of the posterior cruciate ligament. Four patients declined physical therapy and, in six, the main cause of stiffness could not be found. Seventeen patients did not require surgical therapy for restricted motion; TKA provided significant pain relief and they considered the range of motion achieved to be sufficient. One patient underwent redress 3 months after surgery, but with no success. Repeated releases of adhesions, replacement of a polyethylene liner and revision surgery of the extensor knee structures were performed in 15 patients. In these, the average value of knee flexion increased by 17 degrees only and, in the patients suffering from excessive adhesion production, this value remained almost unchanged. Revision TKA was carried out in four patients, in whom knee joint flexion increased on average by 35 degrees to achieve an average flexion of 83 degrees. DISCUSSION: Restricted motion after TKA has been reported to range from 1.3 % to 12.0 %, but consistent criteria have not been set up. In our study it was 4.14 %. In agreement with the literature data, one of the reasons was pre-operative restricted motion, which was recorded in 16 of 32 patients. Similarly, also in our patients, biological predisposition to excessive production of fibrocartilage associated with adhesions in all knee joint compartments was the major therapeutic problem. Intra-operative fractures, ligament tears requiring post-operative fixation and unremoved dorsal osteophytes lead to the restriction of knee joint motion. By inadequate resection of articular surface, the original joint line may be at a higher level; this results in an increased tension of the posterior cruciate ligament and patella infera development, both influencing knee flexion. In our study, three patients were affected. Knee joint stiffness can also develop in patients declining physical therapy or in whom this is not correctly performed, often for insufficient analgesia. In contrast to the data reported in the literature, 17 of 32 patients in this study had no need for surgical treatment of restricted knee joint motion. Redress under general anesthesia was not effective. For markedly restricted motion of the knee joint, reimplantation can be recommended or, in less severe cases, an intervention on adjacent soft tissues. CONCLUSIONS: Restricted motion of the knee joint after TKA is difficult to treat and, therefore, prevention is recommended. This should include thorough conservative treatment of gonarthrosis, early indication for surgery, prevention of elevation in the joint line and consistent rehabilitation with appropriate analgesia. For severe stiffness of the knee joint, as evaluated by the criteria of Kim et al., revision arthroplasty can be recommended.

[Scintigraphic detection of osteoblast activity after implantation of BAS-0 bioactive glass-ceramic material into long bone defects]. / Scintigrafické vysetrení osteoblastické aktivity po implantaci bioaktivního sklokeramického materiálu BAS-0 do defektu dlouhých kostí.

PURPOSE OF THE STUDY: The aim of the study was to demonstrate, by three-phase bone scintigraphy, radionuclide uptake at the site of defects in long bones filled with the non-resorbable bioactive glass-ceramic material BAS-0 at a long follow-up. MATERIAL: Twenty patients, 14 men and 6 women, operated on between 1990 and 2000 for benign bone tumors or tumor-like lesions localized in the femur, tibia or humerus were comprised in the study. Their average age at the time of operation was 14 years (range, 8 to 24). The diagnoses based on histological examination included juvenile bone cysts in 11, aneurysmal bone cyst in five, non-ossifying fibroma in two, and fibrous dysplasia in two patients. The lesions were localized in the femur, humerus and tibia in 11, five and four patients, respectively. The metaphysis was affected in eight and the diaphysis in 12 patients. METHODS: Clinical, radiological and scintigraphic examinations were carried out at 2 to 12 years (7 years on average) after surgery. The clinical evaluation included subjective complaints and objective findings. Radiographs were made in standard projections and the osteo-integration of glass-ceramic material was investigated. Three-phase bone scans were made and the healthy and the affected limbs in each patient were compared by means of an index. Radionuclide uptake was considered normal when the index value was equal to 1.0, mildly increased at an index value of 1.2, moderately increased at 1.2-1.5 and markedly increased at an index value higher than 1.5. RESULTS: The clinical evaluation showed that, in the patients with glass-ceramic filling of metaphyses, six had no subjective complaints and two reported transient pain. In the patients with implants in diaphyses, subjective complaints were recorded in nine and no complaints in three patients. No inflammatory changes in soft tissues were found. No restriction in weightbearing of the limb treated was reported by any of the patients. On radiography, 18 patients were free from any disease residue or recurrence. Two patients had a residual defect. The bioactive glass-ceramic material BAS-0 was completely incorporated in all patients. On three-phase bone scans, radionuclide distribution on the flow phase and soft tissue phase was symmetrical in both limbs of all patients. For the metaphyseal location of implants, the delayed images demonstrated physiological radionuclide distribution in one patient, mildly increased distribution (index up to 1.2) in four, increased uptake (index up to 1.5) in two patients, and highly increased uptake (index above 1.5) in one patient. For the diaphyseal location of implants, the delayed scans demonstrated slightly increased radionuclide distribution in two, markedly increased in two and highly increased uptake in eight patients. DISCUSSION: The tissue during incorporation of a non-resorbable synthetic material is influenced by stress-shielding. This changes local mechanical signals, which has a negative effect on the adjacent bone tissue. Stress accumulating at the interface of a rigid implant and bone tissue may result in pain, and is detected by scintigraphy as an increased nucleotide uptake, particularly in diaphyseal grafts. CONCLUSIONS: This paper presents problems associated with implantation of the non-resorbable bioactive glass-ceramic material BAS-0 in the treatment of diaphyseal defects of long bones. The results show that, for filling of the defects described herein, non-resorbable glass-ceramic materials are not suitable.

Spontaneous 2D accumulation of charged Be dopants in GaAs p-n superlattices.

In a classical view, abrupt dopant profiles in semiconductors tend to be smoothed out by diffusion due to concentration gradients and repulsive screened Coulomb interactions between the charged dopants. We demonstrate, however, using cross-sectional scanning tunneling microscopy and secondary ion mass spectroscopy, that charged Be dopant atoms in GaAs p-n superlattices spontaneously accumulate and form two-dimensional dopant layers. These are stabilized by reduced repulsive screened Coulomb interactions between the charged dopants arising from the two-dimensional quantum mechanical confinement of charge carriers.

Atomic-precision determination of the reconstruction of a 90 degree tilt boundary in YBa2Cu3O7-delta by aberration corrected HRTEM.

Aberration corrected high-resolution transmission electron microscopy is used to determine the reconstruction of atomic bonds of a 90 degree [100] grain boundary in YBa(2)Cu(3)O(7-delta). A precise measurement of atom positions within the grain boundary and the assessment of the oxygen stoichiometry require at the same time a high control of residual lens aberrations of the electron microscope and a good signal-to-noise ratio. This goal is achieved by the combination of spherical-aberration correction in the microscope with the numerical exit-plane wave function reconstruction from focal series. Atomic column positions for individual cations and anions are determined by the regression analysis of peak maxima in the phase image of the retrieved exit-plane wave function. The measurement accuracy is quantitatively assessed, including the statistical error related to residual noise. Changes in bondlengths between copper atoms and the apical oxygen are measured, indicating the distortion of the square pyramidal oxygen coordination of plane copper sites and the square coordination of chain copper sites in the grain boundary.

Atomic-scale analysis of the oxygen configuration at a SrTiO3 dislocation core.

The atomic structure of a SrTiO3 dislocation is revealed directly by phase-retrieval electron microscopy. In particular, atomic columns of light oxygen are observed simultaneously with the columns of considerably heavier Sr and Ti. A distinct structural modification of the oxygen octahedra at the dislocation core as well as a significant nonstoichiometry, including a deficiency of oxygen, are observed. Deviations from the bulk chemical concentration are quantified column by column by means of structure modeling and quantum-mechanical simulations of the electron scattering process.