Biomechanical evaluation of a bioabsorbable expansion bolt for hamstring graft fixation in ACL reconstruction: an experimental study in calf tibial bone.

INTRODUCTION: The purpose of our study was to evaluate and compare the primary fixation strength of a novel bioabsorbable two shell expansion bolt (EB) with that of a well-established interference screw-fixation technique in hamstring reconstruction of the anterior cruciate ligament. MATERIALS AND METHODS: Thirty calf tibia plateaus (age 5-6 months) were assigned to three groups: In group I (n = 10) triple-stranded hamstring grafts were fixed with titanium interference screws (7 mm thread / 8 mm head x 25 mm). Specimens of group II (n = 10) received bioabsorbable poly-L-lactide interference screws (8 x 23 mm). In group III (n = 10), the grafts were fixed using bioabsorbable poly-D,L-lactide expansion bolts (5.8/8.5/10 mm x 35 mm). The tensile axis was placed parallel to the bone tunnel. The construction was then loaded until failure under a displacement rate of 1 mm per second. RESULTS: There were no significant differences concerning the maximum pullout force (group I: 357 N +/- 61; group II: 326 N +/- 92; group III: 343 N +/- 55). In case of the expansion bolt, we found the stiffness to be higher (61 N/mm) when compared to group I (48 N/mm), and group II (52N/mm) (P < 0.01 I vs. III). Using interference screws, we were able to demonstrate a strong correlation between torque and pullout forces (group I: r2 = 0.7; group II: r2 = 0.92). Ruptures of the suturing material occurred only in groups I and II. CONCLUSION: We conclude that hamstring graft fixation, using the presented expansion bolt, demonstrates fixation strength similar to the established screw fixation and can therefore be regarded as a reasonable alternative fixation method. Especially, since some specific disadvantages of screw fixation can be prevented by application of the bolt fixation.

Ambient and biological monitoring of coke plant workers -- determination of exposure to polycyclic aromatic hydrocarbons.

OBJECTIVES: The aims of this study were to determine external and internal polycyclic aromatic hydrocarbon (PAH) exposure in a coke plant and to contribute to the evaluation of biological limit values. METHODS: Personal air sampling was carried out on a study population of 24 coke plant workers. In detail, 16 PAHs were determined, among them phenanthrene, pyrene and benzo[ a]pyrene. For the determination of internal exposure, post-shift urine samples from the workers were examined for hydroxylated metabolites of pyrene (1-hydroxypyrene, 1-OHP) and phenanthrene (1-, 2+9-, 3-, 4-hydroxyphenanthrene, 1-, 2+9-, 3-, 4-OHPhe). In both cases, approved HPLC methods were used. RESULTS: The workers were classified into three groups. The group most exposed was that on the top side of the coke oven, with a mean value of 491.2 microg/m(3) for the sum of all sixteen PAHs. The mean value at the bench side was 26.61 microg/m(3), while it was 76.18 microg/m(3) in the group of workers with no dedicated location (=complete area). Both the excretion of 1-OHP and the sum of hydroxyphenanthrenes had the highest mean levels in the top side group of workers (mean: 19.70 microg/g creatinine (crea.) and 39.18 microg/g crea.), followed by the bench-side workers (mean: 7.01 microg/g crea. and 12.95 microg/g crea.) and the whole-area workers (mean: 3.57 microg/g crea. and 8.70 micorg/g crea.). The concentrations of all urinary metabolites correlated significantly with benzo[ a]pyrene (BaP) in the air. CONCLUSIONS: According to these correlations, urinary concentrations of 8 and 11 microg 1-OHP/g crea., respectively 16 and 23 microg/g crea. for the sum of hydroxyphenanthrenes, correspond to BaP concentrations in air of 2 and 5 micorg/m(3), the German technical guiding concentration (TRK value). Our results are in line with others reported in the literature. That means that it should be possible today to define a standard of occupational hygiene and medicine in coke plants using the elimination of hydroxyphenanthrenes and hydroxypyrene in urine as markers for internal PAH exposure.

Treatment of dye wastewater containing acid orange II using a cell with three-phase three-dimensional electrode.

The removal of color and chemical oxygen demand (COD) from simulated dye wastewater containing Acid Orange II was experimentally investigated using coagulation-electrooxidation. Two kinds of coagulation methods, ferrous-mediated coagulation and electrocoagulation were tested as pretreatment. The electrooxidation was carried out in a cell with a three-phase three-dimensional electrode using granular activated carbon as particle electrodes. Particular attention was paid to probe the effect of cell voltage, airflow rate, solution conductivity and treatment time on the electrochemical treatment efficiency. The experimental results showed that the coagulation-electrooxidation process could efficiently remove the color and the COD from the simulated dye wastewater. The overall COD and color removal efficiencies reached as high as 99% and 87%, respectively, by ferrous coagulation (molar rate of Fe(II)/ dye: 0.5) and 30-min electrolysis (cell voltage: 20.0 V and airflow: 0.1 m3 h(-1)).

[Violence in families and its prevention. Also a plea for abolishing the parental right to inflict physical punishment. A report of the "Violence Commission" of the federal government]. / Gewalt in Familien und ihre Verhinderung. Zugleich ein Plädoyer für die Abschaffung des elterlichen Züchtigungsrechtes. Ein Bericht aus der Arbeit der "Gewaltkommission" der Bundesregierung.

Violence in families is rather frequent. Different forms of violent acts can be distinguished: violence between partners, violence between parents and children, violence among siblings, and violence against elder family members. This report gives an overview--with the emphasis on violence in families--of the work of the "Violence Commission" of the Federal Government. This commission worked out proposals for intervention in the case of intrafamiliar violence as well as for prevention. Two proposals of the commission are explained in detail: (1) Rejection of violence and prohibition of corporal punishment in education and (2) punishability of conjugal violation.

[Diagnosis and therapy of psychoses (author's transl)]. / Diagnose und Therapie der Psychosen.

We apply the same diagnostic principles for the acute schizophrenic episode of the youngster as we do for the adult. The slowly progressive psychoses are characterized by though disorders, creation of extreme alternatives to their view of life, and a loss of shame. An organic process has to be ruled out as differential diagnosis of these psychoses as well as manic depressive illnesses. The different therapeutic aspects will be demonstrated.