Qualification of the Low-pressure Cold Gas Spraying for the Additive Manufacturing of Copper-Nickel-Diamond Grinding Wheels.

Grinding wheels are usually manufactured by powder metallurgical processes, i.e., by molding and sintering. Since this requires the production of special molds and the sintering is typically carried out in a continuous furnace, this process is time-consuming and cost-intensive. Therefore, it is only worthwhile for medium and large batches. Another influencing factor of the powder metallurgical process route is the high thermal load during the sintering process. Due to their high thermal sensitivity, superabrasives such as diamond or cubic boron nitride are very difficult to process in this way. In this study, a novel and innovative approach is presented, in which superabrasive grinding wheels are manufactured by thermal spraying. For this purpose, flat samples as well as grinding wheel bodies were coated by low-pressure (LP) cold gas spraying with a blend of a commercial Cu-Al2O3 cold gas spraying powder and nickel-coated diamonds. The coatings were examined metallographically in terms of their composition. A well-embedded superabrasive content of 12 % was achieved. After the spraying process, the grinding wheels were conditioned and tested for the grinding application of cemented carbides and the topographies of both the grinding wheel and the cemented carbide were evaluated. Surface qualities of the ground surface that are comparable to those of other finishing processes were reached. This novel process route offers great flexibility in the combination of binder and hard material as well as a cost-effective single-part and small-batch production.

Direct hospital costs for patients with inflammatory bowel disease in a Canadian tertiary care university hospital.

OBJECTIVE: We set out to determine the direct costs of hospitalizations of patients with Crohn's disease and ulcerative colitis admitted to a university-affiliated tertiary care hospital and to contrast the costs of medical versus surgical inpatient care, Crohn's disease versus ulcerative colitis, and to identify dominant components of inpatient costs. METHODS: We used a patient-specific case costing system at Saint Boniface General Hospital, Winnipeg, Manitoba, for fiscal years 1994 and 1995. We extracted all inpatients whose hospital discharge abstracts included ICD-9-CM codes 555 (Crohn's disease) and 556 (ulcerative colitis) among the top eight discharge diagnoses, and performed a chart review on all cases to ensure that the hospitalization was for inflammatory bowel disease and the diagnoses were accurate. We analyzed cases based on their disease diagnosis, primary mode of therapy associated with the hospitalization (medical vs surgical), and their major diagnosis-related group (DRG). This study evaluated direct patient care costs only and costs are expressed in Canadian dollars. RESULTS: Of 362 hospital admissions, 325 were eligible and of these admissions 275 belonged to the digestive system DRGs. Seventy-one (37%) were admitted more than once during the 2 yr of the study, accounting for 202 (62%) of the total number of admissions. The mean cost per admission of all cases of Crohn's disease was $3,149 (95% confidence interval [CI], $2,665-$3,634) and for ulcerative colitis was $3,726 (95% CI $3,008-$4,445). Surgical therapy cases accounted for 49.8% of all admissions, 57.8% of all hospital days, and 60.5% of all costs. Patients treated surgically had more costly hospitalizations than those treated medically, particularly when analyzing only nontotal parenteral nutrition (TPN) cases. Surgical treatment admissions were significantly more costly for ulcerative colitis digestive DRG admissions than Crohn's disease. The nondigestive DRG admissions were more costly than the digestive DRGs in all categories although this was only statistically different among medically treated Crohn's disease. Patients treated medically were similarly costly whether they had Crohn's disease or ulcerative colitis. There was no significant difference in cost per admission among cases admitted multiple times, compared with those admitted only once. TPN cases accounted for 9.5% of cases but 27.1% of costs. TPN-associated hospitalizations were more costly than non-TPN-use hospitalizations but these costs were primarily driven by duration of stay rather than TPN use itself. For all cases, the top five cost categories in descending order were nursing unit bed-days, drugs and pharmacy, diagnostic lab tests, operating room, and diagnostic imaging and endoscopy. CONCLUSIONS: Using our system we could determine direct costs for inpatients with inflammatory bowel disease and the factors that determined increased costs. Medical therapy admissions were similarly costly between Crohn's disease and ulcerative colitis; however, surgical therapy admissions were costlier among ulcerative colitis patients. Admissions for nondigestive DRGs were more costly than those for digestive DRGs. TPN use identified a sicker group of patients who remained in the hospital longer than nonusers and, not surprisingly, these were the costliest patients.

[Adenosine deaminase activity in blood cells; influence of cytostatic therapy in patients with acute leukemia and with renal transplants (author's transl)]. / Adenosin-Deami ase-Aktivität inBlutzellen; Einfluss der zytostatischen Therapie bei Patienten mit akuter Leukämie und mit Nierentransplantaten.

A causal relation between the enzyme, adenosine deaminase (ADA), and immune dysfunction is well known: patients with congenital inactivity of ADA invariably suffer of severe combined immunodeficiency. In contrast, we found in patients treated with immunosuppressive drugs increased ADA enzyme activity. Previous findings on ADA activity in acute leukemias are until now controversial. We found normal to increased ADA activity in children with acute lymphatic leukemia (ALL) and acute myeloid leukemia (AML) in remission as long as they were treated with cytostatic drugs. In the group of cured leukemics (in continuous remission after suspension of the therapeutic regimen) the ADA activities were normal. These findings do not exclude a heterogeneity within the leukemia group. They do not explain the signs of cellular immunodeficiencies well known in patients with acute leukemias.

Nitroblue tetrazolium (NBT) test in children with acute lymphoblastic leukemia or malignant lymphomas.

In sixty children with acute lymphoblastic leukemia, Hodgkin's disease or lymphosarcoma 121 determinations of the NBT test were performed in various periods of disease. All the children studied were free of infectious complications. In acute lymphoblastic leukemia the NBT test values were low during relapses of the disease and increased above normal values in the period of remission. In the group with Hodgkin's disease an increase of the NBT test values was always associated with the active stage of the disease. No significant differences between the relapse and the remission period were found in children with lymphosarcoma.

[Immunological aspects in the L-asparaginase treatment of children with lymphoproliferative diseases]. / Immunologische Aspekte bei der L-Asparaginase-Behandlung von Kindern mit lymphoproliferativen Erkrankungen

A group of 20 children, including 14 with acute lymphoblastic leukemia and 6 with lymphosarcoma, was studied. 24 cures of l-asparaginase therapy were carried out. The increase of serum immunoglobulin (IgG, IgA, IgM) levels was found in children treated with smaller (from 300 to 500 I.U./kg b. w.) doses of asparaginase. In the group treated with higher doses (from 501 to 760 I.U./kg b. w.) the maximal increase of immunoglobulins was observed in the second half of the cure with l-asparaginase, followed by a decrease of the immunoglobulins levels at the end of treatment. The presence of anti-asparaginase antibodies in two children with anaphylactic shocks after l-asparaginase has been shown. In these two children and 6 others the lymphocyte count significantly dropped down on the day of shock before l-asparaginase injection.

[Repeated, 2-10 fold asparaginase treatments in children with lymphoproliferative diseases]. / Mehrfache, 2- bis 10malige Asparaginase-Behandlung bei Kindern mit lymphoproliferativen Erkrankungen

In 42 children being in the advanced stage of an acute lymphoblastic leukaemia as well in 7 children with lymphosarcoma a total of 83 series of treatment with L-asparaginase were carried out. During the first blastic crisis of acute leukaemia 74% of complete or partial remissions could be obtained by two treatments and 52% by the following ones. The best results were obtained by organ manifestations of acute leukaemia (80% of complete or partial remissions). Less satisfactory results were achieved in treating lymphosarcoma. All remissions were only of a short duration.

Immunological aspects of L-asparaginase treatment in children with lymphoproliferative disease.

14 children with acute lymphoblastic leukemia and 6 with lymphosarcoma were treated in 13 cures with 300-500 IU/kg bodyweight/day of L-asparaginase and in 11 cures with 501-760 IU/kg/day. An increase of all fractions of immunoglobulins with maximal values at the end of the cures was observed in the group treated with low doses. In the children receiving the high doses of this drug, an increase was observed only in the first 3 or 4 days of therapy and a decrease occurred at the end of the cure. Decreased IgM levels at the end of therapy were noted in children with acute leukemia. Anti-asparaginase antibodies occurred only in 3 children with anaphylactic shock.