AbstractThis paper presents a case study of an underground crude oil storage project. This storage site is researched with detailed field and laboratory investigations. The layout, cross section, and ...elevation of the caverns are analyzed and designed based on geological and geotechnical information obtained during these investigations. In this study, two-dimensional (2D) elastoplastic analysis is performed using the finite-element code Phase 2D to study the rock mass behavior caused by staged excavation of the cavern (20 m wide×30 m high). The excavation of the cavern is simulated with different stages, i.e., excavation of a pilot tunnel and subsequent side slashing followed by excavation for a pilot bench and subsequent side slashing with a total of three benches. Displacement values obtained analytically are compared with the observed displacement as the excavation progresses. Because the 2D FEM code is based on the plain strain concept, it could not take into account the effect of excavation in other directions that is very obvious at the intersection with tunnels and shafts. Therefore, these intersections were analyzed using a linear three-dimensional (3D) boundary element code, Examine3D. The stability analysis of rock wedges formed from various joint patterns is also studied using the UNWEDGE software based on block theory for each section of the cavern.
The most frequent complications of total hip arthroplasty are septic and aseptic wear-induced loosening. A reliable differentiation between septic and aseptic loosening with current diagnostic tools ...is not possible. Therefore, we examined the diagnostic valency of positron emission tomography (PET) with (18)F-fluorodeoxyglucose (FDG) in cases of septic or aseptic hip arthroplasty loosening compared with conventional triple-phase bone scan (TPBS).
Fifty patients with 70 total hip replacements (symptomatic n=50, asymptomatic n=20) were examined by means of FDG-PET and TPBS to detect septic and aseptic loosening and differentiate between the two. A differentiated algorithm subdivided into categories I-V was developed for FDG-PET. Additionally, standardized uptake values (SUV) were calculated from the lesion with the highest FDG uptake. Interpretations of the TPBS were done according to the criteria described by Wilson. The final diagnosis was based on operative findings including microbiological and histological examinations (n=50), while the remaining asymptomatic arthroplasties (n=20) were integrated into a clinical follow-up (> or =9 months).
Sensitivity/specificity of FDG-PET was 91%/92% (accuracy 91%) compared with 78%/70% (accuracy 74%) for TPBS. A high correlation could be proved between FDG-PET investigation and operative histopathological findings (r(Spear)> or =0.9). No significant differences were found regarding cemented and uncemented implanted hip arthroplasties (p> or =0.05). Calculation of the SUV turned out to be inappropriate as a sole criterion for image interpretation.
FDG-PET is a promising, highly accurate examination method to detect polyethylene and metal wear-induced chronic inflammation followed by periprosthetic osteolysis. In addition, FDG-PET has a significantly higher sensitivity and specificity than TPBS for differentiating between aseptic loosening and infection.
Conventional uncemented femoral stems provide good long-term fixation in patients with a wide range of clinical function. However, preservation of bone stock, and minimally invasive approaches have ...led to exploration into various other implant designs. Short-stem prosthesis focusing on a stable metaphyseal fit have emerged to address these challenges in total hip arthroplasty. The purpose of this study was to evaluate the clinical and radiological results of a newly developed short-stem hip prosthesis AIDA® in context of a single surgeon study.
From February 2009 to December 2013, 72 cementless "AIDA® short stems" (Fa. Implantcast) were implanted by a single surgeon in one study centre via the Watson Jones interval. All patients signed informed consent prior to screening and the study design was approved by the local ethics committee. 51 patients with 52 implants (35 female, 36 male) with a follow-up > 24 months were included in this prospective, controlled clinical trial. The patients were pre- and postoperatively examined clinically and radiological by a specified protocol.
The average patient age at the time of THA was 61 ± 3.2 years (min.-max. 46-68 years). At the last follow-up, the average Harris Hip score increased from 41.4 ± 4.5 preoperatively to 96.8 ± 3.2 points postoperatively. The hospital stay was 9.1 days on average. The X-rays showed in all cases a stable fixation of the stems with full bony integration and no signs of loosening or migration. There were no specific complications relating to the less invasive approach. Postoperatively one periprosthetic fracture was evident. The revision operation into a cementless stem was done without any complications (revisions rate 1.9 %).
The newly developed "AIDA short stem" is a promising hip implant for the young and active patient with osteoarthritis of the hip. The short-term results are encouraging, but nevertheless mid- and long-term results must be further observed on a prospective basis as part of this collective study.
Introduction
Hydrolytic debonding of the metal-cement interface is one of the main reasons for aseptic loosening in cemented hip arthroplasty.
Materials and methods
BiContact femur stems ...(CoCrMo-/TiAl
6
V
4
-alloy) were coated by a silica/silane interlayer coating system. The stems were cemented into artificial femurs. The cyclical loading (DIN ISO 7206-4) was performed within a hip-simulator. Uncoated stems (CoCrMo-/TiAl
6
V
4
-alloy) were prepared and loaded the same way. After loading, the metal-cement and the bone-cement interfaces were analysed. Unloaded uncoated and unloaded coated BiContact stems served as a control.
Results
The coated loaded stems showed a significant reduction in debonding and cement failure (
P
≤ 0.05). A high correlation was documented between debonding and cement failure (
r
Spear
≥ 0.9). There was no significant difference between CoCrMo- and TiAl
6
V
4
-stems (
P
≥ 0.05).
Conclusion
The silica/silane coating significantly decreased hydrolytic debonding at the metal-bone cement interface with consecutively less cement failure.
The significant developments in the genetic selection of fast-growing broiler chickens cause difficulties for broilers in coping with extreme environmental conditions. This study was conducted to ...elucidate the effect of repetitive short-term increases in incubation temperature on hatchability and chick's body weight (BW) and thermoregulation immediately after hatch. Thermal manipulation (TM) had no effect on hatchability when the three trials were combined for statistical analysis, and had no effect on chick's BW. It caused a significant reduction in chicks
T
b, and significant decline in plasma thyroid hormones concentration, but had no effect on plasma corticosterone concentration. It can be concluded that TM did not affect BW but had a positive effect on thermoregulation, most probably in reducing metabolic rate.
Abstract The aim of this study is to define stem design related factors causing both gaps in the metal–bone cement interface and cracks within the cement mantle. Six different stem designs (Exeter; ...Lubinus SP II; Ceraver Osteal; Mueller-straight stem; Centega; Spectron EF) ( n =15 of each design) were cemented into artificial femur bones. Ten stems of each design were loaded, while five stems served as an unloaded control. Physiologically adapted cyclical loading (DIN ISO 7206-4) was performed with a hip simulator. After loading both interfaces and the bone cement itself were analysed regarding gaps and cracks in the cement mantle. Significant differences between the stem designs concerning gaps in the metal–bone cement interface and cracks in the cement mantle became apparent. Additionally, a high correlation between gaps in the metal–bone cement interface and cracks within the cement mantle could be proven. Gaps in the metal–bone cement interface but no cracks within the cement mantle were seen in the unloaded specimens. Differences between the unloaded control groups and the cyclical loaded stems regarding the longitudinal extension and width of gaps in the metal–bone cement interface were obvious. The designs of cemented femoral stems have an influence on both the quality of the metal–bone cement contact and the failure rate of the cement mantle. Less interface gaps and less cement defects were found with anatomically formed, collared, well-rounded stem designs without undercuttings.
Liberalism, in the nineteenth-century sense of the term, came to Austria much later than it came to western Europe, for it was not until the 1840s that the industrial revolution reached the Hapsburg ...Empire, bringing in its train miserable working conditions and economic upheaval, which created bitter resentment among the working classes and a longing for a Utopia that would cure the ills of mankind. This new-found liberalism, largely self-contained and uninfluenced by liberal movements outside the empire, centered mainly in the idea of individual freedom and constitutional monarchism. In the end, the revolution failed because the moderates proved too weak to control the radical excesses, and the radicals in growing desperation tried to turn the rebel idea into a democratic and, at the extreme, a republican one. Fear of this extremism finally drove the moderates into the counterrevolutionary camp. Since the Viennese rebels fought to achieve many of the goals fundamental to democracy, historians have generally tended to idealize the revolutionaries and forget their shortcomings. R. John Rath has sought to evaluate the revolution from the point of view of the political ideologies of 1848 rather than those of the mid-twentieth century. Moreover, he has clearly and objectively stated the case for both the left and the right, pointing out the failures and shortcomings of each. At its publication, this was the first detailed English-language book on the Viennese Revolution of 1848 in more than a hundred years. The author has not confined himself to the bare bones of history. In his descriptions of the times and lively portrayals of the chief actors of the revolution, he has vividly restaged a drama of an ideal that failed.
In the context of a case control study on the cancer risk for children under five by distance to the nearest nuclear power plant, we collected information on other risk factors in a subset. We ...present the interview study as if it had been an independent study. Parents of 471 cases with Leukaemia, Lymphoma or CNS (Central Nervous System)-tumour from the German Childhood Cancer Registry, diagnosed at age under 5 in the years 1993-2003, and 1,457 matched controls were to be interviewed. For Leukaemia, 243 cases/604 controls, and for CNS 102 cases/246 controls participated, lymphoma cases were too few. Questions related to social status, ionizing radiation, pregnancy and birth, immune system, and selected toxins. The analysis is exploratory in nature; variables were selected by backward elimination. For leukaemia we found a significant protective effect of social contacts (OR=0.50, 95% CI 0.29;0.87) and a risk for high birth weight (OR=1.96 95% CI 1.12;3.41 comparing >4,000 g to "normal"). We could not reproduce other associations reported in the literature such as a negative association with allergies. For CNS tumours we found a significant protective effect of social contacts (OR=0.30 95% CI 0.13;0.72), of pesticides and herbicides (OR=0.39 95% CI 0.18;0.83) and an increased risk for low birth weight (p=0.0232). This study on risk factors for childhood leukaemia and brain tumours is relatively small and exploratory. We could reproduce some major associations reported in the literature (leukaemia: social contacts and high birth weight) but not others. Some observations may be reporting artefacts or self selection artefacts.
When Austrian soldiers first set foot in Lombardy-Venetia in October, 1813, they were greeted everywhere as liberators and friends. In the spring of 1815, when Joachim Murat's efforts to establish a ...united Italy ended in miserable failure and when the Habsburgs announced the main features of the regime they intended to establish in their Italian provinces, the Venetians were still strongly pro-Austrian, but considerable anti-Habsburg feeling had developed among the Lombards. This carefully documented study of the first two years of Austrian reoccupation of Lombardy-Venetia examines all aspects of the Habsburg provisional regimes and draws some conclusions about the reasons for the different attitudes in the two provinces. In detailed sketches of the provisional governments of Venetia (Chapter I) and Lombardy (Chapter II) and an examination of Austrian economic policies and practices in both provinces (Chapter III), the author shows that although the governments of the two provinces shared many common traits, they differed in a number of significant ways. Actually, Venetia was much less efficiently governed than Lombardy; and the Lombards enjoyed at least a small measure of self-administration that was largely denied the Venetians. The Lombards were much more prosperous than their neighbors, yet they paid much less in taxes and were exempt from most of the burdensome military requisitions that the Austrians inflicted on the Venetians. In spite of these advantages, the relatively small nationalist movement in Austria's Italian provinces was almost entirely confined to Lombardy. The author examines public opinion in Lombardy-Venetia about liberal intrigues (Chapter IV); the relationship of secret societies to liberalism (Chapter V); the Brescian-Milanese conspiracy (Chapter VI) and the Austrian handling of that affair (Chapter VII); and the fiasco of Joachim Murat's "War of Italian Independence" (Chapter VIII).
Adsorption, electrokinetic and flotation studies have been carried out to investigate the interaction of dextrin with sphalerite and galena. The adsorption density of dextrin onto sphalerite ...increases with increase of pH up to pH 7.5, and thereafter decreases, while that onto galena shows a maximum around pH 11.5. It is observed that the adsorption density of dextrin onto galena is quite high compared to that on sphalerite. Both the adsorption isotherms exhibit Langmuirian behaviour. Electrokinetic measurements reveal that the isoelectric points of sphalerite and galena are located around pH 3. The electrophoretic mobilities of both the minerals become less negative following polymer adsorption without any apparent shift in the isoelectric points. Dissolution experiments indicate release of metal ions from sphalerite and galena, while, co-precipitation tests confirm polymer–metal ion interaction in the bulk solution. Flotation tests show that dextrin effectively depresses galena in the pH range of 10 to 12 but not sphalerite, complementing the adsorption results. Differential flotation results indicate that sphalerite can be separated from its synthetic mixture with galena using dextrin as a depressant for galena at pH 12.1. Possible mechanisms of interaction between the two sulphide minerals tested and dextrin are discussed.
