A suggested effective method for unidirectional solidification under rotating magnetic field in the space experiments

In order to save costs and time during the unidirectional solidification experiments, it is necessary to obtain more and more information by solidifying one sample in a rotating magnetic field (RMF) to be performed on the space station. The macro- and microstructure developing during solidification is significantly influenced by the intensity and frequency of magnetic field, the solid/liquid interface velocity as well as the temperature gradient. A method by which one of the aforementioned four parameters can repeatedly be changed during the solidification is described. By this method, the transient phenomena occurring during parameters modification can also be observed. The results of earth experiments carried out by this method with Al7Si1Fe alloy are presented.     

A tracer interaction method for nonlinear pharmacokinetics analysis: application to evaluation of nonlinear elimination

A drug tracer is most commonly applied to get information about the pharmacokinetics (PK) of a drug that is not confounded by an endogenously produced drug or an unknown drug input. An equally important use of tracers that has not been fully recognized is their use in the study of nonlinear PK behavior. In the present study a system analysis is applied to examine the interaction between drug molecules characteristic and intrinsic to any nonlinear process which enables the nonlinearity to be identified and modeled using a drug tracer. The proposed Tracer Interaction Methodology (TIM) forms a general developmental framework for novel methods for examining nonlinear phenomena. Such methods are potentially much more sensitive and accurate than previous methods not exploiting the tracer principle. The methodology proposed is demonstrated in a simulation study and with real data in a specific implementation aimed at determining the Michaelis-Menten (MM) parameters of nonlinear drug elimination while accounting for drug distribution effects. The simulation study establishes that the TIM-based, MM parameter evaluation produces substantially more accurate parameter estimates than a nontracer (NT) conventional method. In test simulations the accuracy of the TIM was in many cases an order of magnitude better than the NT method without evidence of bias. The TIM-based, MM parameter estimation methodology proposed is ideally suitable for dynamic, non-steady-state conditions. Thus, it offers greater applicability and avoids the many problems specific to steady state evaluations previously proposed. TIM is demonstrated in an evaluation of the nonlinear elimination behavior of erythropoietin, a process that likely takes place via receptor-based endocytosis. Due to its high sensitivity, accuracy, and intrinsic nonlinearity the TIM may be suitable for in-vivo studies of receptor binding of the many biotechnology produced peptide drugs and endogenous compounds displaying receptor-mediated elimination.     

A novel variable-gravity simulation method: potential for astronaut training

Zero gravity conditions for astronaut training have traditionally used neutral buoyancy tanks, and with such tanks hypogravity conditions are produced by the use of supplemental weights. This technique does not allow for the influence of water viscosity on any reduced gravity exercise regime. With a water-foam fluid produced by using a microbubble air flow together with surface active agents to prevent bubble agglomeration, it has been found possible to simulate a range of gravity conditions without the need for supplemental weights and additionally with a substantial reduction in the resulting fluid viscosity. This new technique appears to have application in improving the simulation environment for astronaut training under the reduced gravity conditions to be found on the moon or on Mars, and may have terrestrial applications in patient rehabilitation and exercise as well.     

A new method for measuring the effective radiating area of physiotherapy treatment heads

This paper describes the investigation and validation of a new method for measuring the effective radiating area (AER) of physiotherapy ultrasound treatment heads. The method is based on the use of a conventional radiation force balance, but employs special attenuating apertures that are used to selectively mask off different areas of the treatment head. The resultant reduction in the radiating surface is accompanied by a decrease in output power that is measured using the force balance. The AER of the treatment head is derived from an analysis of the measurements, which essentially involves initially evaluating the minimum area through which 75% of the acoustic power is transmitted. AER values derived using the new method are presented for 17 treatment heads representative of the range of physiotherapy systems commonly used in clinical practice. These are compared to reference values derived using hydrophone scanning, according to the recently published International Standard, IEC 1689. Typical levels of agreement between values of AER derived using the two techniques are +/- 11%. The potential of the method as a rapid, relatively low-cost, means of measuring treatment head AER, applicable in both manufacturing and hospital environments, is assessed.     

A qualitative field method for monitoring pesticides in the edge-of-field runoff

A field method is described, which allows the qualitative estimation of pesticide contamination in the edge-of-field runoff. The method employs cheap and easy-to-use runoff sampling bottles, which were installed in an agricultural stream catchment over a period of three growing seasons. During this time 18 runoff events were detected, in nine of which insecticide contamination was measured (maximum concentrations: lindane 0.7 microgram l-1 and 12.7 micrograms kg-1, parathion 20 micrograms l-1 and 728 micrograms kg-1, fenvalerate 18.4 micrograms l-1 and 924 micrograms kg-1). These insecticides were detected mainly as particle-bound chemicals. On about 80% of the occasions the presence or absence of runoff measured in the field was in agreement with a simulation of runoff presence or absence using the runoff model KINEROS.     

The LineFinder: a new method for finding the bone center line and femoral head center point

A plastic template-type device with a central slot is described. This device allows rapid identification of the center line of long bones and the center point of femoral heads.     

Hypothesis: interventions that increase the response to stress offer the potential for effective life prolongation and increased health

In the last decade it has become evident that many laboratory manipulations, both genetic and environmental, can lead to significant life extension. All or almost all of the observed life-extension phenotypes are associated with increased resistance and/or ability to respond to environmental stress. These observations show dramatically that life span is not maximized. We suggest that latent within many species-perhaps even humans-is the ability for large increases of life expectancy. The striking correlation between the increased stress resistance of all long-lived mutants in C. elegans and other species and the increased resistance of dietary restricted rodents to environmental toxins is consistent with an evolutionary conservation of a life-span maintenance/environmental stress resistance program. We suggest that it may be possible to develop methods for life extension in mammals, including humans, using relatively straightforward manipulations, such as drug treatments. It should be obvious that these findings have tremendous implications for human society at large, and we suggest that the implications of these findings should be explored.     

多媒体技术与教学方法有机结合的初探

近年来教育界有种倾向,似乎运用多媒体进行教学俨然成了"时尚",一旦有公开课、示范课、教研课,教师必然使用多媒体技术教学.有人认为高质量的优质课应是采用了先进的教学手段产生出的多媒体教学,有些院校将课堂是否采用多媒体作为衡量教师课堂教学质量的一个指标.     

A compensation method for the disturbance in the temperature field caused by subsurface thermocouples

The presence of a subsurface thermocouple hole can lead to a local disturbance of the temperature field in a sample and to a discrepancy between the thermal history measured by the thermocouple and the thermal history in an area without a thermocouple. This phenomenon also leads to errors in the surface heat flux calculated using an inverse heat conduction model, which relies on the acquired thermal history data. This article analyzes the factors that influence the temperature discrepancy caused by a subsurface thermocouple hole. A technique called the “equivalent depth” technique is proposed to compensate for the disturbance of the temperature field due to the presence of a thermocouple hole. This technique involves off-setting the location of the thermocouple position based on the radius of the thermocouple hole. A verification of this technique for the calculation of the surface heat flux using an inverse heat conduction model with measured thermal history data is presented.     

A field trial of Billings' ovulation method for spacing and limitation of birth

In spite of constant efforts by health and social workers, existing family planning measures are not used by a vast majority of eligible couples. This is because of the fear that the method may affect their health and happiness. Billings' ovulation method is based on the scientific observation that by noting the changes in cervical mucus, which is clear, slippery and copious in periovulatory period, it is possible to prevent pregnancy by avoiding intercourse during this period. As this method does not require the use of drugs or devices it was decided to promote this method in the urban areas and slums of Patna, Bihar where couples were not using other methods. This is not a comparative study of the cost-effectiveness of Billings' ovulation method versus other contraceptive measures at all. An analysis of 501 cases (267 in urban and 234 in slums) over a period of 2 1/2 years has been presented and it is gratifying to note that the couples from all religions and strata of the society (nearly 47% were slum dwellers) agreed to continue this method.     

Pyridoxal isonicotinoyl hydrazone and its analogs: potential orally effective iron-chelating agents for the treatment of iron overload disease

At present, the only iron (Fe) chelator in clinical use for the treatment of Fe overload disease is the tris-hydroxamate deferoxamine (DFO). However, DFO suffers from a number of disadvantages, including the need for subcutaneous infusion (12 to 24 hours a day, 5 or 6 times per week), its poor intestinal absorption, and high cost. Therefore, there is an urgent need for an efficient, economical, and orally effective Fe chelator. Pyridoxal isonicotinoyl hydrazone (PIH) is a tridentate Fe-chelating agent that shows high Fe chelation efficacy both in vitro in cell culture models and also in vivo in rats and mice. In addition, this chelator is relatively nontoxic, economical to synthesize, and orally effective, and it shows high selectivity and affinity for Fe. However, over the last 10 years the development of PIH and its analogs has largely been ignored because of justifiable interest in other ligands such as 1,2-dimethyl-3-hydroxypyrid-4-one (L1). Unfortunately, recent clinical trials have shown that significant complications occur with L1 therapy, and it is controversial whether this chelator is effective at reducing hepatic Fe levels in patients. Because of the current lack of a clinically useful Fe chelator to replace DFO, PIH and its analogs appear to be potential candidate compounds that warrant further investigation. In this review we will discuss the studies that have been performed to characterize these chelators at the chemical and biologic levels as effective agents for treating Fe overload. The evidence from the literature suggests that these ligands deserve further careful investigation as potential orally effective Fe chelators.