An X-ray study of particulate solids flow in a cylindrical bunker

The noise generated by a ball mill during a batch grinding operation is investigated and the results show that, for a given ore, the noise levels may vary with time of grind, ore charge weight and mill speed. The role of the ore in absorbing noise energy is suggested as a possible control variable for the grinding process and as an indicator of product size distribution. The relationship between ore types and mill noise is also examined and, under conditions of wet grinding, it is demonstrated that mill noise analysis can indicate ore type and may have a possible use as a grindability-type parameter.     

Detection of serum antibody responses in cattle with natural or experimental Neospora infections

Parasite-specific antibody responses were detected using an indirect fluorescent antibody (IFA) test in cattle that were naturally or experimentally infected with Neospora parasites. The test was developed using Neospora tachyzoites isolated from an aborted bovine fetus and grown in bovine cell cultures (isolate BPA1). In all cases, infections were confirmed by the identification of Neospora tachyzoites and/or bradyzoite cysts in fetal or calf tissues using an immunoperoxidase test procedure. Fifty-five naturally infected cows that aborted Neospora-infected fetuses had titers of 320-5,120 at the time of abortion. The titer of 6 cows that were serologically monitored over a prolonged period decreased to 160-640 within 150 days after they aborted infected fetuses. Two of the cows showed an increase in their Neospora titers during their subsequent pregnancy, and they gave birth to congenitally infected calves that had precolostral titers of 10,240-20,480. Postcolostral titers of these calves and of 4 other calves with congenital Neospora infections were all > or = 5,120, whereas calves with no detectable parasites had titers < or = 160. Two pregnant heifers that were experimentally infected with the BPA1 isolate at approximately 120 days gestation seroconverted to Neospora antigens within 9 days and developed peak titers of 5,120 and 20,480 within 32 days of infection. The fetus taken by caesarean section 32 days postinfection from 1 heifer and the full-term calf born to the other had Neospora titers of 640 and 10,240, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Rate of cerebrospinal fluid formation, resistance to reabsorption of cerebrospinal fluid, brain tissue water content, and electroencephalogram during desflurane anesthesia in dogs

Propofol decreases intraocular pressure (IOP) and the IOP response to laryngoscopy and intubation, but the mechanisms responsible for this effect have not been reported. The present study examined the effect of propofol on IOP, intraocular fluid formation and outflow facility, and intraocular compliance. Twenty-two white New Zealand rabbits were anesthetized with halothane (0.8%-1.0% inspired concentration) in nitrous oxide (2 L/min) and oxygen (1 L/min). Muscle paralysis was established with pancuronium, and the lungs were mechanically ventilated through a tracheal tube. Twelve rabbits examined under these conditions served as controls. In the treatment group (n = 10), 6 mg/kg propofol followed by 18 mg.kg-1 x h-1 propofol intravenously was added to halothane/nitrous oxide/oxygen anesthesia. In both groups, a series of intraocular infusions was made via a 30-gauge needle in the anterior chamber, and IOP, the rate of aqueous humor formation (Fa), and trabecular outflow facility (Ctr) were determined using conventional analysis. These same measures, as well as intraocular compliance, were determined using a new method of analysis adapted from the manometric technique for determining cerebrospinal fluid dynamics. IOP was 11.3 +/- 1.8 mm Hg (mean +/- SD) in halothane-anesthetized controls and decreased to 9.4 +/- 2.2 mm Hg when propofol was added to halothane anesthesia (P < 0.05). By conventional analysis, Fa was 2.82 +/- 0.94 microL/min and Ctr was 0.121 +/- 0.044 microL.min-1 x mm Hg-1 in controls. After addition of propofol, Fa decreased by 24% to 2.15 +/- 0.62 microL/min (P < 0.05) and Ctr decreased by 18% to 0.099 +/- 0.034 microL.min-1 x mm Hg-1 (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Salt-tolerant and thermostable alkaline protease from Bacillus subtilis NCIM no. 64

The proteolytic activity produced by a Bacillus subtilis isolated from a hot spring was investigated. Maximum protease production was obtained after 38 h of fermentation. Effects of various carbon and nitrogen sources indicate the requirement of starch and bacteriological peptone to be the best inducers for maximum protease production. Requirement for phosphorus was very evident, and the protease was secreted over a wide range of pH 5-11. The partially purified enzyme was stable at 60 degrees C for 30 min. Calcium ions were effective in stabilizing the enzyme, especially at higher temperature. The enzyme was extremely salt tolerant and retained 100% activity in 5M NaCl over 96 h. The molecular weight of the purified enzymes as determined by SDS-PAGE was 28,000. The enzyme was completely inactivated by PMSF, but little affected by urea, sodium dodecyl sulfate, and sodium tripoly phosphate.     

Large specimen bone embedment and cement line staining

Undecalcified embedment of large bone specimens is often challenging. A method is presented here that is suitable for methacrylate embedment of sections of canine vertebrae while retaining the ability to localize tartrate-resistant acid phosphatase and alkaline phosphatase activity. Specimens also retained tetracycline labelling, and sectioned preparations were readily stained with routine bone procedures. A modification of the Bodian silver stain, used for examining the nerves and spinal cord in these specimens, provided a useful stain for canaliculi and cement lines in trabecular and cortical bone. This stain is advantageous when both bone and nerve tissue are of interest, as in spinal fusion studies.