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BACKGROUND: In end-stage renal disease, average bone mineral density has been reported to be normal or only modestly reduced, more so in the cortical bone. The purpose of the present study was to explore the potential use of quantitative ultrasound, a method reflecting both quantitative and qualitative properties of bone, in assessing bone status in patients on maintenance haemodialysis. METHODS: We studied 71 patients (age 17-81 years, time on dialysis 0-18 years). The speed of sound waves (tSOS; m/s) propagating along the cortical bone has been determined at the tibial shaft. tSOS results were expressed as Z scores, i.e. units of standard deviations from age- and sex-matched normal mean values, and correlated with relevant clinical and biochemical variables. RESULTS: SOS Z score averaged -2. 0 (range -6.8 to 0.6; P<0.001) and was negative in 93% of the patients. Significant inverse correlations were found between SOS Z score and both time on dialysis (r=-0.52; P<0.0001) and serum PTH (r=-0.39; P=0.0002). Markedly reduced SOS Z score, below -2, was found in 80% of the patients whose PTH levels exceeded 34 pmol/l (five times the upper normal limit), compared with 43% of the patients whose PTH levels were below 34 pmol/l(P=0.04). Compared to patients without bone pain (n=51), subjects with bone pain (n=20) had somewhat lower SOS Z scores -2.5+/-2.0 versus -1.8+/-1.4; P=0. 08), but this could be accounted for by longer time on dialysis. CONCLUSIONS: tSOS is substantially reduced in the majority of haemodialysed patients and is related to time on dialysis and serum PTH level. The clinical value of this novel method needs further exploration.  相似文献   
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A whole genome scan was undertaken in a granddaughter design comprising 1158 progeny-tested bulls in order to map QTL influencing milk yield and composition. In this paper we report the identification of a locus on the centromeric end of bovine Chromosome (Chr) 14, with major effect on fat and protein percentage as well as milk yield. The genuine nature of this QTL was verified using the grand2-daughter design, that is, by tracing the segregating QTL alleles from heterozygous grandsires to their maternal grandsons and confirming the predicted QTL allele substitution effect.  相似文献   
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We describe here a bacterial sensor for electrochemical detection of toxic chemicals. The sensor constitutes recombinant bacteria harboring plasmids encoding the fabA and fabR genes and has high-resolution amperometric response to membrane-damaging chemicals. For example, it can detect phenol at concentrations ranging between 1.6 and 16 ppm within 20 min. The high sensitivity is achieved by using the fabA promoter fused to a reporter gene-encoded beta-galactosidase on a low copy number plasmid, under the control of the FabR repressor. The use of electrochemical whole cell sensors enables sensitive, fast, easy to operate, and cost-effective detection of water toxicity threats.  相似文献   
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Sonodynamic therapy (SDT) triggered by ultrasound (US) has attracted increasing attention owing to its abilities to overcome critical limitations including low tissue‐penetration depth and phototoxicity in photodynamic therapy. Herein, the design of a new type of sonosensitizer is revealed, namely, ultrasmall oxygen‐deficient bimetallic oxide MnWOX nanoparticles, for multimodal imaging‐guided enhanced SDT against cancer. As‐made MnWOX nanoparticles with poly(ethylene glycol) (PEG) modification show high physiological stability and biocompatibility. Interestingly, such MnWOX‐PEG nanoparticles exhibit highly efficient US‐triggered production of 1O2 and ?OH, higher than that of previously reported sonosensitizers (e.g., protoporphyrin IX and titanium dioxide), because the oxygen‐deficient structure of MnWOX serves as an electron trap site to prevent electron–hole recombination. The glutathione depletion capability of MnWOX‐PEG can also further favor SDT‐triggered cancer cell killing. With efficient tumor homing as illustrated by computer tomography and magnetic resonance imaging, MnWOX‐PEG enables effective destruction of mouse tumors under US stimulation. After accomplishing its therapeutic functions, MnWOX‐PEG can be metabolized by the mouse body without any long‐term toxicity. Herein, a new type of sono‐sensitizing agent with high SDT efficacy, multimodal imaging functions, and rapid clearance is presented, an agent which is promising for noninvasive SDT cancer treatment.  相似文献   
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ISSUES: General definitions of quality assurance and quality control (QA/C) have existed in many forms for decades, and a new discipline guides their application to diverse industrial and recently medical processes without much fanfare. However, in the field of cervical cytology screening, the range of QA/C options has recently broadened and become controversial. With the advent of new systems of terminology, larger-scale laboratories and new technologies--plus strong governmental and legal pressures in some nations--the range of extremely difficult and sometimes expensive QA/C choices our community faces is greater than ever. CONSENSUS POSITION: At our conference, the basic definitions of QA/C posed little difficulty. Presentation of the range of methods in use today and of those based on new technologies where use is proposed or has just begun also was achieved with little or no dispute. However, there was lack of consensus on exactly how QA/C methods are to be assessed. Indeed, there was little consistency in the use of different outcome measures with which we can judge success or failure of specific QA/C options. In addition, the tension between pressure to adopt sometimes uncertain or expensive method enhancements and pressure to maintain affordability and the widest possible access for populations that most need cervical cytology screening is greater than ever. ONGOING ISSUES: More data are required that would enable assessment of QA/C options with the clearest possible understanding of cost/benefits and current or new assumptions of risk. Other task forces, such as medicolegal, cost/benefit and those devoted to new technologies, are our essential partners in meeting the challenges described above.  相似文献   
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An electrochemical nano-biochip for water toxicity detection is presented. We describe chip design, fabrication, and performance. Bacteria, which have been genetically engineered to respond to environmental stress, act as a sensor element and trigger a sequence of processes, which leads to generation of electrical current. This novel, portable and miniature device provides rapid and sensitive real-time electrochemical detection of acute toxicity in water. A clear signal is produced within less than 10 min of exposure to various concentrations of toxicants, or to stress conditions, with a direct correlation between the toxicant concentration and the induced current.  相似文献   
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In this paper we propose the use of spontaneous galvanic displacement as a promising solution to produce nickel foam electrodes functionalized with interconnected platinum nanoparticles. Scanning Electron Microscopy analyses, coupled with X-ray Energy Dispersive Spectroscopy show that, under proper conditions, we can overcome the limits of other deposition techniques, achieving a uniform Pt coverage throughout the 3D structure of the Ni foam. We show that such a condition, not deeply investigated in previous literature, turns out to be crucial for the long term stability of the electrodes under constant current stress. The amount of Pt on the Ni foam has been experimentally evaluated, obtaining optimal results with 0.015 mg cm?2 of noble metal in a 0.16 cm thick electrode. Such a low amount corresponds to a Ni foam cost increase of less than 0.1%.  相似文献   
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We prospectively investigated the appropriateness of Mechanism of Injury as an exclusive indicator for trauma center triage. For all patients transported to our level 1 trauma center, EMS personnel identified applicable American College of Surgeons' Committee on Trauma field triage guidelines. A total of 112 questionnaires were completed. Mechanism of injury was the only reason for trauma center transport in 29. Neither intubation nor emergent surgery was required in any of these patients, and all survived. Only two had an ISS > 15. The remaining 83 patients had an 11% mortality rate. Fourteen (16.9%) had ISS scores > 15. Defining an ISS of 16 or greater as severe injury, mechanism of injury alone had a positive predictive value of only 6.9%. Mechanism of injury may not, by itself, justify bypass of local hospitals in favor of trauma centers.  相似文献   
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