Rationalisierung des Zeichnungswesens im Chemie-Apparatebau

Rationalizing drawings for chemical apparatus . For small and medium-sized manufacturers of apparatus, producing drawings may constitute a disproportionate waste of time and personnel, particularly when no new designs are involved but only modification or improvement of drawings supplied by the customer. One possibility for rationalizing drawing is to simplify the old-fashioned approach by using symbols for frequently drawn or standard items, or by listing alphanumerically. This presumes a kind of systematization permitting determination of those symbols and their reasonable use, as well facilitating rationalization by means of data processing. There are different approaches to computer-aided drawing (from computer controlled drawing-board to interactive screens); here a CAD programme is presented which was especially developed for graphic presentation of chemical apparatus, and which can be used without learning a programming language.     

Prognostic significance of cathepsin-D in patients with breast cancer

The expression of the protease cathepsin-D has been evaluated using an immunohistochemical technique with a polyclonal antibody in paraffin-embedded tissue from 359 patients treated between the years 1975-1981 for Stage I and II breast cancer. One hundred and twenty seven patients (35%) have strongly positive, granular staining, 138 (38%) are intermediately stained in the cytoplasm, and in 94 (26%) no staining is observed. There is a strong positive association between expression of cathepsin-D and the presence of tumour in axillary lymph nodes (P < 0.006). Expression of the protease is associated with significantly poorer survival of patients in univariate analysis (P = 0.025); however, this is not independent of other tumour variables.     

Surface Modification of Titania Nanoparticles Using Ultrathin Ceramic Films

Surface modification of titania nanoparticles was achieved by coating them with ultrathin alumina films using atomic layer deposition. The coating process was performed in a fluidized bed reactor at low pressure and under mechanical vibration. Films were deposited using self-limiting, sequential surface reactions of trimethylaluminum and water. The composition of alumina-coated particles was verified using infrared spectroscopy. The deposited films had an average growth rate of 0.2 nm/coating cycle and were highly uniform and conformal as demonstrated by transmission electron microscopy and X-ray spectroscopy. Deposited alumina films were amorphous as verified through X-ray diffraction and high-resolution electron microscopy. The coating process did not promote particle sintering as validated via particle size and surface area analysis.     

Ambient-pressure thermogravimetric characterization of four different coals and their chars

Ambient-pressure thermogravimetric characterization of four different coals and their chars was performed to obtain fundamental information on pyrolysis and coal and char reactivity for these materials. Using a Perkin-Elmer TGS-1 thermobalance, weight loss as a function of temperature was systematically determined for each coal heated in helium at 40 and 160 °C/min under various experimental conditions, and for its derived char heated in air over a temperature range of 20 to 1000 °C. The results indicate that the temperature of maximum rate of devolatilization increases with increasing heating rate for all four coals. However, heating rate does not have a significant effect on the ultimate yield of total volatiles upon heating in helium to 1000 °C; furthermore, coupled with previous data⁹ for identical coal samples, this conclusion extends over a wide range of heating rate from 0.7 to 1.5 × 10⁴ °C/s. Using the temperature of maximum rate of devolatilization as an indication of relative reactivity, the devolatilization reactivity differences among the four coals tested that were suggested by this criterion are not large. For combustion in air, the overall coal/char reactivity sequence as determined by comparison of sample ignition temperature is: N. Dakota lignite coal ≈ Montana lignite coal > North Dakota lignite char > III. No. 6 bituminous coal ≈ Pittsburgh Seam bituminous coal > Montana lignite char > III. No. 6 bituminous char > Pittsburgh Seam bituminous char. The reactivity differences are significantly larger than those for devolatilization. The reactivity results obtained suggest that coal type appears to be the most important determinant of coal and char reactivity in air. The weight loss data were fitted to a distributed-activation-energy model for coal pyrolysis; the kinetic parameters so computed are consistent with the view that coal pyrolysis involves numerous parallel first-order organic decomposition reactions.     

Isolation and characterization of acid- and bile-tolerant isolates from strains of Lactobacillus acidophilus

Lactic acid bacteria have been reported to be useful as a health adjunct and are commonly added to food as the delivery mechanism. The literature contains many conflicting observations for their proposed benefits, and the mechanism of action is undefined. One source of variation is the large number of strains used without proper controls supplemented. Additionally, many of the organisms are not characterized for their acid shock response or the acid-tolerance response, which are known to vary among bacterial species. Our objective was to isolate acid-resistant and bile-resistant variants of Lactobacillus acidophilus and to determine the phenotypic changes. The acid- and bile-tolerant isolates were obtained using natural selection techniques after sequential exposure to hydrochloric acid (pH 3.5 to 7.0) and mixed bile salts. The acid- and bile-tolerant isolates retained their ability to grow at pH 3.5 with 0.3% bile after the selective pressure was removed and reapplied. Isolates varied from their parents for stability in freezing, lactose utilization, protease activity, aminopeptidase activity, plasmid profile, and cell-wall fatty acid profile. These data suggest that the isolated acid- and bile-tolerant isolates possess growth advantages over that of the parents under stress conditions and may be considered as candidates for probiotic strains after further characterization with animal models.     

New protein genetic studies in six Amazonian Indian populations

A total of 732 individuals affiliated with six Amazonian Indian populations were variously studied in relation to 26 protein genetic systems. Eleven of them were found to be monomorphic in these groups, in accordance with previous investigations. Similarities and dissimilarities (the latter involving the Rh, Duffy, haptoglobin and transferrin systems) were observed in relation to earlier investigations in four of these populations (Galibi, Palikour, Mundurucu and Tenharim). A dimeric, cathodal variant of albumin was found among two Galibi subjects, and the fairly common occurrence of CP* ACAY among some South American Indian populations was confirmed. The results in the six populations were compared with those from 29 others. When relationships are searched for among tribes of the same linguistic group, the factor that seems to be most influential is geographical localization, an exception being the pattern observed among the Cayapo subgroups. The latter shows genetic differences of the same level of magnitude as those observed among Ge-speaking tribes.     

Nanoparticle Coating for Advanced Optical,Mechanical and Rheological Properties

Primary titania nanoparticles were coated with ultrathin alumina films using Atomic Layer Deposition (ALD). The deposited films were highly uniform and conformal with an average growth rate of 0.2 nm per coating cycle. The alumina films eliminated the surface photocatalytic activity of titania nanoparticles, while maintained their original extinction efficiency of ultraviolet light. Deposited films provided a physical barrier that effectively prevented the titania surface from oxidizing organic material whereas conserving its bulk optical properties. Parts fabricated from coated powders by pressureless sintering had a 13 % increase in surface hardness over parts similarly fabricated from uncoated particles. Owing to its homogeneous distribution, the secondary alumina phase suppressed excessive grain growth. Alumina films completely reacted during sintering to form aluminum titanate composites, as verified by XRD. Coated particles showed a pseudoplastic behavior at low shear rates due to modified colloidal forces. This behavior became similar to the Newtonian flow of uncoated nanoparticle slurries as the shear rate increased. Suspensions of coated particles also showed a decreased viscosity relative to the viscosity of uncoated particle suspensions.     

Transient changes in milk production efficiency and bacterial community composition resulting from near-total exchange of ruminal contents between high- and low-efficiency Holstein cows

The objectives of this study were to determine if milk production efficiency (MPE) is altered by near-total exchange of ruminal contents between high- (HE) and low-MPE (LE) cows and to characterize ruminal bacterial community composition (BCC) before exchange and over time postexchange. Three pairs of ruminally cannulated, third-lactation cows were selected whose MPE (energy-corrected milk per unit of dry matter intake) differed over their first 2 lactations. Approximately 95% of ruminal contents were exchanged between cows within each pair. Ruminal pH and volatile fatty acid (VFA) profiles, along with BCC (characterized by sequencing of the variable 4 region of 16S rRNA genes), were assessed just before feeding on d ?8, ?7, ?5, ?4, ?1, 1, 2, 3, 7, 10, 14, 21, 28, 35, 42, and 56, relative to the exchange date. High-MPE cows had higher total ruminal VFA concentrations, higher molar percentages of propionate and valerate, and lower molar percentages of acetate and butyrate than did LE cows, and re-established these differences 1 d after contents exchange. Across all LE cows, MPE increased during 7 d postexchange but declined thereafter. Two of the 3 HE cows displayed decreases in MPE following introduction of the ruminal contents from the corresponding LE cow, but MPE increased in the third HE cow, which was determined to be an outlier. For all 6 cows, both liquid- and solids-associated BCC differed between individuals within a pair before contents exchange. Upon exchange, BCC of both phases in all 3 pairs was more similar to that of the donor inoculum than to preexchange host BCC. For 5 of 6 cows, the solids-associated community returned within 10 d to more resemble the preexchange community of that host than that of the donor community. Individual variability before the exchange was greater in liquids than in solids, as was the variability in response of bacterial communities to the exchange. Individual cows varied in their response, but generally moved toward re-establishment of their preexchange communities by 10 d after contents exchange. By contrast, ruminal pH and VFA profiles returned to preexchange levels within 1 d. Despite the small number of cows studied, the data suggest an apparent role for the ruminal bacterial community as a determinant of MPE.     

Modification of interparticle forces for nanoparticles using atomic layer deposition

Silica and titania nanoparticles were individually coated with ultrathin alumina films using atomic layer deposition (ALD) in a fluidized bed reactor. The effect of the coating on interparticle forces was studied. Coated particles showed increased interactions which impacted their flowability. This behavior was attributed to modifications of the Hamaker coefficient and the size of nanoparticles. Stronger interparticle forces translated into a larger mean aggregate size during fluidization, which increased the minimum fluidization velocity. A lower bed expansion was observed for coated particles due to enhanced interparticle forces that increased the cohesive strength of the bed. Increased cohesiveness of coated powders was also determined through angle of repose and Hausner index measurements. The dispersability of nanopowders was studied through sedimentation and z-potential analysis. The optimum dispersion conditions and isoelectric point of nanoparticle suspensions changed due to the surface modification. A novel atomic force microscope (AFM) technique was used to directly measure interactions between nanoparticles dispersed on a flat substrate and the tip of an AFM cantilever. Both Van der Waals and electrostatic interactions were detected during these measurements. Long and short range interactions were modified by the surface coating.