Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “pulverization”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 181 records · Page 10Linked to original sources
PubMed2005

Effect of tablet geometrical structure on the dehydration of creatine monohydrate tablets, and their pharmaceutical properties.

The effects of compression and pulverization on the dehydration kinetics and hardness of creatine monohydrate tablets were studied using a variety of kinetic equations and physical models. The dehydration behavior of unpulverized and pulverized tablets was investigated by using differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD). The hardness of both unpulverized and pulverized monohydrate tablets was significantly decreased after dehydration. The relationship between the degree of dehydration and the tablet hardness of both unpulverized and pulverized monohydrate tablets formed a straight line. The results suggest that the reduction in tablet hardness is dependent on the dehydration of crystal water, and the values of the slopes indicate that the bonding energy of the unpulverized sample was stronger than that of the pulverized sample. The dehydration kinetics of the unpulverized and pulverized monohydrate tablets were evaluated by analyzing the fit of the isothermal DSC data using a variety of solid-state kinetic models. The dehydration of the unpulverized tablets at various levels of compression pressure followed the 3-dimensional growth of nuclei mechanism. In contrast, although the dehydration kinetics of pulverized monohydrate tablets compressed at 500 and 750 kg/cm2 followed the 3-dimensional diffusion mechanism, those compressed at 1000 kg/cm2 followed the 3-dimensional growth of nuclei mechanism. The PXRD analysis indicated that the diffraction intensity of the pulverized monohydrate powder was significantly lower than that of the unpulverized powder. The diffraction peaks of the (h00) planes and the micropore structure of the unpulverized monohydrate tablets were affected by pulverization and compression force, respectively.

Compressive Strength↗
PubMed2026

Evaluation of bone preparation approaches using length-based analysis and targeted sequencing for forensic human identification of historic skeletal remains.

Advances in DNA technology have significantly enhanced the forensic community's ability to develop genetic profiles from unidentified human skeletal remains. However, sampling requires mechanical grinding of hard tissues before DNA isolation. This processing can compromise genetic profiles, particularly in aged bones. We compared the industry-standard pulverization method with an alternative powder-free preparation involving prolonged demineralization and subsequent slicing of 19th-century cortical bone. Data from DNA quantification, STR genotyping, and targeted SNP sequencing were used to evaluate powdered samples versus demineralized slices from paired human bones. Average human DNA yields for pulverized samples and demineralized slices were 0.032&#x2009;ng and 0.692&#x2009;ng, respectively. Demineralized slices recovered more amplifiable DNA than traditional homogenization methods (p&#x2009;<&#x2009;0.05). No pulverized samples produced STR profiles, whereas demineralized slices from the same bone samples yielded partial profiles. Samples underwent DNA repair, library preparation, and hybridization capture using the FORensic Capture Enrichment (FORCE) panel. Applying low-coverage (1X) analysis of high-throughput sequencing (HTS) data, demineralized slices outperformed those prepared by traditional pulverization methods (p&#x2009;<&#x2009;0.05) and substantially increased the information recovered compared with conventional STR analysis methods. Based on HTS data from pulverized samples, DNA fragment length ranged from 27 to 95&#x2009;bp, and FORCE SNP recovery was 33.23%. In contrast, for demineralized slices, DNA fragment length ranged from 85 to 114&#x2009;bp, and FORCE SNP recovery was 83.24%. The required reagents and equipment are typically available in forensic labs, and the workflow outlined herein significantly increases the success of DNA recovery from challenging skeletal samples.

Humans↗
PubMed1988

Myocardial ischemia and reperfusion: direct evidence for free radical generation by electron spin resonance spectroscopy.

Electron spin resonance spectroscopy has recently been used by others to detect directly radical species in isolated perfused hearts. Sample processing prior to spectroscopy in this study involved pulverization of tissue, which can artifactually generate radical species. We assessed in isolated perfused hearts the influence of tissue pulverization on the identity of radical species detected by spectroscopy and then, using a processing technique less likely to induce artifacts, whether myocardial ischemia and reperfusion generate radical species. Rat and rabbit hearts (n = 8) were perfused aerobically for 10 min and freeze-clamped to -196 degrees C. Frozen tissue was processed at -196 degrees C for spectroscopic analysis by pulverization vs. chopping. Spectra of pulverized tissue consisted of three components: a semiquinone (g = 2.004), a lipid peroxy radical (g [ = 2.04 and g = 2.006), and a carbon-centered radical that is possibly a lipid radical (giso = 2.002 and AHzz approximately equal to 50 G). Chopped tissue consisted of a single component, a semiquinone (g = 2.004). Rat hearts (n = 8 per group) also underwent 10-min global no-flow normothermic ischemia followed by 5-60 sec of either aerobic or anaerobic reperfusion, with frozen tissue chopped prior to spectroscopy. Spectra of ischemic tissue consisted of an iron-sulfur center and a semiquinone. Aerobic reperfusion resulted in a spectrum similar to the control but with increased amplitude that peaked after 10-15 sec of reflow. Anaerobic reperfusion yielded a spectrum identical to that of ischemic tissue. We conclude that pulverization of frozen myocardial tissue arti-factually generates radical species. Using a nonpulverization technique for tissue processing, we found that myocardial ischemia and reperfusion produce radical species but that molecular oxygen is necessary for the burst of radical production during reflow.

Aerobiosis↗
PubMed1999

[Optimized extracorporeal shockwave lithotripsy of gallbladder calculi: a prospective randomized therapy comparison].

UNLABELLED: Is "pulverization" or "fragmentation" the best endpoint of extracorporeal shock wave application in ESWL of gallbladder stones? Has gallbladder motility a potential for the prevention of stone recurrence? METHODS: Prospective, monocentric study with randomization between the conventional treatment strategy (endpoint of shock wave application: fragments < or = 4 mm, concomitant oral chemolitholysis) and an intensified treatment strategy (endpoint of shock wave application: Pulverization, no chemolitholysis). Prevention of stone recurrence: At least once per month for one hour after a meal standardized position (back position, lowered chest). RESULTS: 34 patients, age 46 +/- 14 years (27 women, seven men) were included (F-ESWL: n = 18; P-ESWL: n = 16). Gallbladder motility, number, size and CT-measured calcifications of stones were comparable for both groups. P-ESWL patients received more shock wave pulses than F-ESWL patients and more treatment sessions. P-ESWL resulted in a better fragmentation and pulverization of stones was reached significantly more often (p < 0.05). The time period for stone clearance was significantly depending on the fragmentation result (pulverization: 0.7 months vs. fragments < or = 4 mm: 6.6 months vs. fragments > or = 4 mm: 8.0 months; p < 0.01). The stone free rate after twelve months was 87.5% for P-ESWL and 72.2% for F-ESWL (n.s.) and correlated significantly with the fragmentation result (p < 0.01). Pain sensations during stone clearance were significantly reduced by P-ESWL. Stonefree patients were followed up for 30 +/- 13 months, the total recurrence rate was 7.1%. CONCLUSIONS: Aiming for pulverization of gallbladder stones by means of intensified extracorporeal shock wave application is at least equal or in tendency superior compared to disintegration to fragements < or = 4 mm. Gallbladder motility might be useful to prevent gallstone recurrence after successful ESWL.

Adult↗
PubMed1981

The behavior of allocyclic chromosomes in Bloom's syndrome.

The behavior of individual allocyclic chromosomes has been analyzed in lymphocytes of a sister and a brother with Bloom's syndrome. Of 4,633 46 diploid cells, 115 showed allocyclic chromosomes, and 74 of these had 44, 45 or 46 normal metaphase chromosomes accompanied by one or two allocyclic chromosomes. Of 56 tetraploid cells, 9 contained such chromosomes. The allocyclic chromosomes appeared "pulverized" or extended corresponding to S or G2 PCC. We have proposed the hypothesis that individual allocyclic chromosomes do not, as a rule, come from micronuclei, as has often been assumed, but have been left behind in their cycle. This would be caused by a mutation or deletion of a hypothetical coiling center situated near the centromere of each chromosome arm. The following observations agree with our explanation but less well or not at all with the idea of micronuclei: (1) In only 9.6% of the cells does the allocyclic chromosome lie at the edge of the metaphase plate. (2) In 24 cells a part of a chromosome is "pulverized" while the rest is in metaphase. (3) Both a "pulverized" and an extended chromosome were present in the same cell. (4) A "pulverized" acrocentric is often nose-to-nose with a normal D or G chromosome. (5) No allocyclic chromosomes corresponding to G1 PCC have been found in our material. (6) When a ring is replaced by an allocyclic chromosome, it is usually a member of a 46-chromosome complement. Furthermore, the occurrence of allocyclic chromosomes is correlated with that of other chromosome anomalies which do not follow a Poisson distribution. Allocyclic chromosomes are also more frequent (16%) in tetraploid than in diploid cells (2%).

Bloom Syndrome↗
PubMed2002

A study of control strategy for the bin system with tube mill in the coal fired power station.

The pulverized coal systems with tube mills are widely used in coal fired power plants. As there are many controlled variables and disturbances in this system, and startup and shutdown of the system is frequent and the dynamic characteristic of the controlled plant is also extraordinary, the automatic control system for this kind of pulverized coal system is not ideally implemented for long. The authors of this paper investigated and tested a pulverized coal system with tube mill in Nanjing Thermal Power Station, and based on various different controlled plants and control objectives, proposed rather independent control subsystems. These subsystems can organize a whole automatic control system of pulverized coal system that can be used in different conditions. The control system presented in this paper has worked well since it was put into operation in May 1998, and good economic benefits have been acquired.

Algorithms↗
PubMed1971

Induction of nuclear envelopes around metaphase chromosomes after fusion with interphase cells.

The process of cellular fusion induced by Sendai virus in Chinese hamster cells (Don line) afforded us the opportunity to study nuclear envelope formation around metaphase sets in the presence of interphase nuclei, when chromosome pulverization failed to occur in such multinucleate cells. Morphologically, the enveloped metaphase chromosomes resembled a normal telophase nucleus, though minor differences prompted us to call it telophase-like. Electron microscopic observations demonstrated that the membranes enveloping the chromosomes appeared to be identical with a normal nuclear envelope. The longer the cells were incubated with Colcemid before fusion, the higher was the number of cells with telophase-like nuclei and the lower the percentage of cells with pulverizations. Furthermore, the number of pulverizations bore a somewhat direct relationship to the ratio of metaphase to interphase nuclei in multinucleate cells, and the number of telophase-like nuclei was inversely proportional to this ratio. A hypothesis is advanced in which a balance between the activities of a chromosome pulverization factor and a nuclear envelope formation factor, the former in metaphase cells and the latter in interphase cells, is decisive as to the nature of morphologic events observed in virus-induced fused cells.

Animals↗
PubMed1989

[The detection of Clostridium botulinum in fecal samples of cattle and swine and in the raw material and animal meal of different animal body rendering plants].

Fecal samples of cattle and swine and samples of raw material and pulverized dehydrated meat taken from three rendering plants were investigated with special enrichment methods on the presence of Clostridium botulinum to get a view about the hygienic risk by the incidence of C. botulinum in rendering plants. Eight-six specimens were examined: 25 fecal specimens each of swine and cattle, 11 of raw material and 25 of pulverized dehydrated meat of three rendering plants. Twelve specimens contained C. botulinum: 7 fecal specimens, 6 of swine and one of cattle, 4 raw material specimens and one of pulverized dehydrated meat. C. botulinum was detected by its toxin production in culture medium. Six times C. botulinum type E, twice C. botulinum type B and one time C. botulinum type C was identified. C. botulinum could not be typed in other cases because the toxin quantities were too small. C. botulinum type E was detected in raw material and pulverized dehydrated meat in one of the three examined rendering plants.

Animals↗
PubMed1997

[In vitro study of urinary calculi fragmentation with 4 different systems of lithofragmentation].

The results of shockwave lithofragmentation are conditioned by stone composition. Similarly, the different types of lithofragmenting energy can have different effects on the calculi. The purpose of this experimental study is to establish a relationship between calculi composition and type of energy used for fragmentation, with the results of the lithotriptsy treatment. 60 calculi, 12 for each pure composition selected (calcium oxalate mono and dihydrate, phosphocarbonate, ammonium magnesium phosphate and uric acid) underwent in vitro lithofragmentation with 4 different lithofragmenting sources (electrohydraulic, piezoelectric, ultrasound and pulsed laser). It was carried out a study of fragmentation in particles under 3 mm and pulverization in particles under 0.5 mm, analyzing post-lithotriptsy fragments with scanning electron microscopy associated to X-ray dispersion energy. No relationship was shown between calculi composition and amount of energy supplied for the fragmentation. The lithiasic composition correlates to the fragmentation pattern, so that oxalocalcium calculi undergoes good fragmentation and poor pulverization, infective calculi have poor fragmentation but good pulverization and uric acid calculi show poor fragmentation and pulverization.

Humans↗
PubMed1999

Elution parameters and HPLC-detection of single components from resin composite.

The toxic effects of mercury derived from amalgam fillings have been a focus of controversy in Germany during the last 25 years. As alternatives to amalgam, composites are used widely to restore anterior and posterior permanent teeth. This study quantifies the amount of TEGDMA and methacrylic acid that can be derived from a polymerized commercial hybrid composite material. Different specimens were made with different curing methods with and without an oxygen inhibition layer. To simulate the removal of composite fillings, some samples were pulverized. The specimens were eluted in distilled water at 37 degrees C for different time intervals. To check the influence of acid conditions, pulverized material was incubated in 6 M HCl. The separation of the eluted chemical resin components was done by HPLC. A defined mixture of pure components was used as an external standard for the identification and quantification of the eluted components. The results focus on the release of triethylengly-coldimethacrylate (TEGDMA) and methacrylic acid. Concerning the different incubation methods, the results showed higher TEGDMA elution with oxygen inhibited surface layer and with the pulverized samples. Within acid conditions, the amount of TEGDMA found was low, but the amount of methacrylic acid increased. Small resin monomers like TEGDMA are primarily eluted from composite in aqueous solutions. Within acid conditions a hydrolytic disintegration of the ester bonding of the monomers could be observed. Methacrylic acid--a substance with allergenic potential--could be detected.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1992

High-performance liquid chromatographic determination of nifedipine and a trace photodegradation product in hospital prescriptions.

A HPLC method is developed for the assay of nifedipine and trace amounts of a photodegradation product in pulverized tablets used in the preparation of hospital prescriptions. After liquid-liquid extraction, nifedipine and its photodegradation product are chromatographed using a reversed-phase system which involves UV detection at 254 nm and the use of two internal standards. The trace photodegradation product in pulverized tablets is determined along with nifedipine by the same procedure. The method is capable of determining 0.5-5.0 micrograms of nifedipine using p-nitronifedipine as the internal standard and 0.01-0.5 micrograms of the photodegradation product using 5-hydroxynifedipine as the internal standard. The standard error is found to not exceed 8.4%. The methods are useful for the study of the disposition or photostability of nifedipine in tablets and pulverized tablets.

Chromatography, High Pressure Liquid↗
PubMed2002

Explosibility boundaries for fly ash/pulverized fuel mixtures.

Incomplete combustion and subsequent fuel contamination of a waste stream can pose a serious explosion hazard. An example of this type of incident is the contamination of fly ash with unburned pulverized coal. The coal, if present in sufficient quantities in the mixture, can act as a fuel source for a potential explosion. Experiments were conducted in a 20l Siwek explosibility test chamber to determine the minimum fuel contamination of fly ash required to form an explosible mixture. A sample of fly ash from Ontario Power Generation (OPG) (Ont., Canada) was artificially contaminated with Pittsburgh pulverized coal dust (the surrogate used to represent unburned fuel dust). Additionally, the influence of fly ash particle size on the amount of fuel contaminant required to form an explosible mixture was examined. Fine and coarse size fractions of fly ash were obtained by screening the original sample of OPG fly ash. The results show that at least 21% Pittsburgh pulverized coal (or 10% volatile matter) was required to form an explosible mixture of the original fly ash sample and coal dust. The results also illustrate that fly ash particle size is important when examining the explosibility of the mixture. The fine size fraction of fly ash required a minimum of 25% coal dust (12% volatile matter) in the mixture for explosibility, whereas the coarse fly ash required only 10% coal dust (7% volatile matter). Thus, the larger the particle size of the inert fly ash component in the mixture, the greater the hazard.

Coal↗