Life cycle of hydroprocessing catalysts and total catalyst management

Hydroprocessing catalysts based on Ni, Co, Mo and W are used in various refinery processing applications where several deactivation mechanisms become of importance (coke formation, active phase sintering, metals deposition, poisoning) in the catalyst's life cycle. The life cycle of commercial hydroprocessing catalysts is very complex and includes the catalyst production, sulfidation, use, oxidative regeneration followed by re-sulfidation and reuse or, if reuse is not possible, recycling or disposal. To understand the changes in catalyst properties taking place during a life cycle, the catalyst quality in the different stages can be best monitored by using advanced analytical techniques. The catalyst's life cycle is further complicated by numerous technical, environmental and organizational issues involved. In principle, different companies can be involved in each of the life cycle steps. Leading catalyst manufacturers, together with specialized firms, offer refineries a total catalyst management concept, starting with the purchase of the fresh catalyst and ending with its final recycling or disposal. Total catalyst management includes a broad range of services, ensuring optimal timing during the change-out process, reliable, smooth and safe operations, minimal downtime and maximum catalyst and unit performance.     

追求质量的七个方向

本文简单介绍了追求质量的七个方向，是公司推行质量管理及正确建立质量方针政策参考的指南。     

Identification of novel simple sequence length polymorphisms (SSLPs) in mouse by interspersed repetitive element (IRE)-PCR

Interspersed repetitive element (IRE)-PCR is a useful method for identification of novel human or mouse sequence tagged sites (STSs) from contigs of genomic clones. We describe the use of IRE-PCR with mouse B1 repetitive element primers to generate novel, PCR amplifiable, simple sequence length polymorphisms (SSLPs) from yeast artificial chromosome (YAC) clones containing regions of mouse chromosomes 13 and 14. Forty-two IRE-PCR products were cloned and sequenced from eight YACs. Of these, 29 clones contained multiple simple sequence repeat units. PCR analysis with primers derived from unique sequences flanking the simple sequence repeat units in seven clones showed all to be polymorphic between various mouse strains. This novel approach to SSLP identification represents an efficient method for saturating a genomic interval with polymorphic genetic markers that may expedite the positional cloning of genes for traits and diseases.     

Intravenous immunoglobulin inhibits IgE production in human B lymphocytes

This study sought to determine the prevalence of spontaneous reperfusion of an infarct-related artery (IRA) and associated myocardial salvage in the absence of thrombolysis or angioplasty. Twenty-one patients with acute myocardial infarction received only heparin and aspirin. At a median of 18 hours after presentation, 12 patients (57%) had angiographic patency of the IRA. Technetium-99m sestamibi was injected acutely on presentation and again at hospital discharge. Acute and final perfusion defect sizes were measured. Their difference, myocardial salvage, was calculated along with salvage index (myocardial salvage/acute defect). Comparing patients with a patent versus occluded IRA, myocardium at risk was similar (16% +/- 12% vs 12% +/- 9% left ventricle, p = NS); however, myocardial salvage (9% +/- 9% vs -2% +/- 7% left ventricle, p = 0.01), and salvage index (0.62 +/- 0.37 vs 0.19 +/- 0.33, p = 0.01) were greater in patients with spontaneous reperfusion. Resolution of chest pain was greater in patients with a patent IRA (100% vs 55%, p = 0.003). Spontaneous reperfusion of the IRA occurs frequently in patients with acute myocardial infarction and is associated with significant myocardial salvage.     

Ecotoxicology and residues of anthelmintic compounds

Anthelmintics and endectocides used for the treatment and prophylaxis of Ostertagia sp. in ruminants include benzimidazoles, levamisole, morantel and the avermectins and milbemycins. Most of these agents are excreted to some extent in the faeces of treated animals and it has been demonstrated that members of the avermectin/milbemycin group may have deleterious effects on non-target organisms utilising the faeces. The environmental impact of antiparasitic chemotherapy depends on the deleterious effect which the agent or its metabolites have on organisms in the locus of the excreta, the amount of active agent excreted, the temporal nature of the excretion and the stability of the ecotoxic residues. These have to be considered in the context of the overall proportion of excreted faeces from a herd which is contaminated and thus the availability of non-contaminated faeces which may act as refugia for dung utilising organisms. The contribution which weathering, faunal inhabitants, trampling by cattle and disturbance by birds have on the rate of dung degradation must also be considered. The greatest ecotoxicological risk is associated with sustained release delivery devices, delivering endectocides with potent activity against dipteran flies and coleopteran beetles. The relatively large proportion of most cattle herds excreting faeces with no endectocidal contamination is likely to reduce the impact that such treatment or prophylactic strategies have on non-target organisms.     

DNA reactions, mutagenic action and stealth properties of polycyclic aromatic hydrocarbon carcinogens (review)

OBJECTIVE: To present a critical review and meta-analysis of studies evaluating the long-term effects of pulmonary rehabilitation in patients with asthma and chronic obstructive pulmonary disease (COPD). DATA SOURCES: A database of articles published over the last 45 years, compiled by using medical subject heading key words pulmonary, obstructive, rehabilitation, and exercise. Articles not written in English, Dutch, or German and abstracts were excluded. STUDY SELECTION: Selected studies (1) evaluated the effects of pulmonary rehabilitation, (2) included patients with asthma or COPD older than 18 years, (3) evaluated outcome measures of exercise capacity or health related quality of life (HRQL), and (4) included a control condition lacking exercise training. DATA EXTRACTION: Independent extraction by two reviewers. DATA SYNTHESIS: For each outcome, summary effects were computed by pooling standardized mean differences as well as raw mean differences. Significant improvements were found for all outcomes (p < .001). Sensitivity analyses for methodological quality of the selected studies did not change summary effect sizes. Effect sizes were significantly heterogeneous for the outcome endurance time (p < .0001). Pooling raw mean differences revealed overall effects in 6-minute walking distance (49+/-26 m) and all 4 dimensions of the chronic respiratory questionnaire (range, 0.5+/-0.3 to 0.8+/-0.3 points), indicating substantial improvements in these outcomes. Significant summary effect sizes were found up to 9 months after finishing rehabilitation for maximal exercise capacity (p < .003) and 6-minute walking distance (p < .005). CONCLUSIONS: Patients with asthma and COPD benefit from pulmonary rehabilitation.     

质量就是符合要求

本文介绍质量成本、实施全过程质量控制、提倡“零缺陷”工作准则等质量管理理念，以此论证“质量就是符合要求”。     

Transgastric endoluminal laparoscopic resection of a duodenal polyp

Transgastric endoluminal surgery is a laparoscopic procedure used to treat gastric lesions such as polyps and carcinoma in situ. This approach can also be used to treat proximal duodenal problems such as bleeding and polyps. Our case was a young patient with bleeding from a benign duodenal polyp, localized 3 cm from the papilla of Vater. Two trocars were introduced by laparoscopy into the stomach. Guided by the flexible gastroscope, the polyp (a 6-cm Brunner's benign hamartoma) was resected by means of the endostaplers. Transgastric endoluminal surgery can be used to extirpate benign lesions in the proximal duodenum. The use of a flexible gastroscope can be very useful because of its adaptability to the anatomy.     

Detection of intravascular injection of regional anaesthetics in children

PURPOSE: Detection of intravascular injection of local anaesthetic during placement of regional blocks in children by using epinephrine-induced tachycardia or hypertension may produce false positive and false negative findings. This study evaluates ECG changes as markers of intravascular injection of local anaesthetics with epinephrine, during placement of epidural blocks in children. METHODS: Observational study in a teaching hospital of all epidural anaesthetics administered to paediatric patients during one year. General anaesthesia, where used, was not controlled. An ECG rhythm strip was recorded during test dose injection and analyzed for changes in rate, rhythm, and T-wave configuration. RESULTS: During the study period, 742 paediatric epidural blocks were administered. There were 644 caudal (284 without catheters), 97 lumbar, and one thoracic epidural anaesthetics. Satisfactory placement was achieved in 97.7% of patients. Intravascular injection was detected in 42 (5.6%) of epidural anaesthetics (3.8% and 6.7% of straight needle and catheter injections, respectively). Detection was by immediate aspiration of blood in six patients, and by heart rate increases > 10 bpm in 30. Five had heart rate decreases suggesting a baroreceptor response. Five had heart rate increases < 10 bpm that were possible responses to noxious stimuli. Of 30 patients with known intravascular injection and for whom ECG strips were available, 25 (83%) had T-wave amplitude increases > 25%, and 29 (97%) had ECG changes in T-wave or rhythm in response to the epinephrine injection. There were no false positives. CONCLUSION: In order to reduce risks associated with epidural anaesthesia in children, epinephrine should be added to the local anaesthetic test dose, the ECG should be monitored continuously for changes in heart rate, rhythm, and T-wave amplitude. Epidural injections should be given in small increments.