The Cancer Genetics Network: recruitment results and pilot studies

OBJECTIVE: The National Cancer Institute established the Cancer Genetics Network (CGN) to support collaborative investigations into the genetic basis of cancer susceptibility, explore mechanisms to integrate this new knowledge into medical practice, and identify ways of addressing the associated psychosocial, ethical, legal, and public health issues. SUBJECTS AND METHODS: The CGN has developed the complex infrastructure required to support the projects, including the establishment of guidelines and policies, uniform methods, standard questionnaires to be used by all of the centers, and a standard format for submission of data to the Informatics Center. Cancer patients and their family members have been invited to enroll and be included in a pool of potential study participants. The Information Technology Group is responsible for support of the design, implementation, and maintenance of the multicenter Network-wide research protocols. RESULTS: As of January 2004, the CGN contained data on 23,995 probands (participants) and 425,798 family members. As a resource for cancer genetic studies, the CGN has a large number of probands and first-degree relatives with and without cancer and with multiple ethnicities. Different study designs can be used including case-control, case-case, and family studies. CONCLUSIONS: The unique resources of the CGN are available for studies on cancer genetic susceptibility, translational research, and behavioral research. The CGN is now at a point where approved collaborators may have access to enrolled patients and their families for special studies, as well as to the clinical, environmental and family cancer history data banked in the Informatics Center.     

Public knowledge and public trust

As health care applications derived from human genetics research are likely to move increasingly from 'clinic to community', there is growing interest not just in how patients understand and take up health-related genetic information but also in the views of the wider population, as well as a range of professional groups. In this paper, issues relating public knowledge and public trust are raised and discussed in an attempt to move forward debates about public involvement in genomic research and the role of sociologists within interdisciplinary teams. As the field of public understanding of science has developed, we have seen a shift from a focus on the lack of scientific literacy as problem to a recognition of the range of different knowledges that people have and use as they confront science and technology in their everyday lives. As a mood for dialogue pervades many institutions in their relations with 'publics', attention must now be paid to the way in which knowledge and expertise is expressed, heard and acted upon in dialogic encounters. There is increasing concern about public trust in science and calls to increase public confidence, particularly through more open engagement with a range of publics. However, lack of trust or loss of confidence may be constructed as problems rather than reflecting empirical reality, where more complex relationships and attitudes prevail. Lack of trust is often privatized, deeply rooted in lived experience and routinely managed. Trust relations are generally characterized by ambivalence, uncertainty and risk, and are always provisional. Drawing on selected literature and empirical research to review and illustrate this field, this paper argues that scepticism or ambivalence on the part of publics are not necessarily problems to be overcome in the interest of scientific progress, but rather should be mobilized to enhance open and public debates about the nature and direction of genomics research, medicine, and the related social and ethical issues. Just as there can be no resolute expression of public knowledge or public opinion, it is unlikely that there is a resolute expression of public trust in genomics. However, ambivalence and scepticism can be harnessed as powerful resource for change, whether through the mobilization of public knowledges or the development of greater reflexivity within scientific institutions. This demands a sharing of power and greater public involvement in the early stages of policy formation and scientific and medical agenda setting.     

Generation of impulsive pressure wave by spark discharge in water and its propagation

An experimental investigation was performed to find a new method for diagnosing three-dimensional flows in which obstacle bodies or cavities are included by means of a pressure wave. In rectangular closed tanks 200 × 337 × 250 mm (acrylic resin) and 300 × 450 × 400 mm (brass) filled with water, an impulsive pressure wave was generated by an instantaneous small spark discharge. The pressure waveforms were measured at a point on the wall with a high-frequency pressure transducer, and the data were recorded with an A/D converter. The measured wave fluctuations differed depending on wall conditions of the tank and on whether there was a submerged body in the water. The size of the submerged body also affected the pressure fluctuation. When acrylic resin and brass were used as wall materials, both the phase and amplitude of the reflecting wave differed. When a stainless steel sphere of diameters of 50.8, 30.2, or 19.1 mm was submerged in the tank, two kinds of pressure waves were observed, one passing through the sphere and the other diffracted around it. These results suggest the possibility of identifying bodies of simple shape by interpreting the precisely measured output pressure wave signals.     

Age at postnatal diagnosis of down syndrome in the northern Netherlands for the period 1981-2000

BACKGROUND: In live-born children with Down syndrome it may be very difficult for the clinician or midwife assisting at the delivery to recognise Down syndrome in newborn babies due to varying physical appearances. Meanwhile more and more therapeutical interventions become available that should start early in life. We were interested in the age at the postnatal diagnosis of Down syndrome, and found no literature on the subject. METHODS: We studied the age at the diagnosis of Down syndrome for live-born babies born in the period of 1981-2000 and registered by the European Registration of Congenital Anomalies in the northern part of The Netherlands. RESULTS: For 289 children, data on the age at the postnatal diagnosis were available, in 70.8% of whom there was suspicion of DS on the day of birth. In 1.7% of the cases, the diagnosis was made after 1 year. Place of birth and the specialty of the health worker assisting at the delivery were associated with age at diagnosis. When the child was delivered at hospital, 96.4% of the Down syndrome cases had been diagnosed within 1 month compared to 81.3% following home delivery. CONCLUSION: In some cases of Down syndrome in live-born babies, the diagnosis is made only after months or a year. The diagnosis was made faster in babies born in hospital compared to those born at home.     

Dynamics of stress wave propagation in a chain of photoelastic discs impacted by a planar shock wave: Part II, numerical investigation

The propagation of stress waves through a chain of discs has been studied experimentally in Part I (Glam et al. [1]) and is completed here with numerical investigation using the standard package ABAQUS. A fair agreement is found between experimental findings and their simulations. Based on this agreement, parametric study of wave propagation through disc-chains was conducted. Specifically, effects associated with changes in the disc diameter, material density, stiffness/rigidity and the number of discs in the chain on the stressed chain have been studied. It was found that the propagation velocity of the evolved waves increases with improving contacts between the chain’s discs by exposing the chain to a static load before its dynamic loading. The wave- propagation velocity decreases with increase in the discs material density and it increases when its diameter increases. In case of a chain composed of small diameter discs and/or small material density, the transmitted stress wave is first strengthened and only at discs further down the chain it starts decaying. When checking the influence of the dynamic-loading duration it was found that long dynamic-load duration dissolves quickly into short pulses. It was also found that there is a ‘characteristic’ wave for a given chain. This wave propagates with minimal dispersion. Dynamic loads having shorter time duration than the ‘characteristic’ one experiences significant attenuation.     

BRCA1/2 mutation carriers: living with susceptibility

OBJECTIVES: To examine whether being a BRCA1/2 mutation carrier affects a wide array of aspects of life, and if so, how. METHODS: Participants were grouped according to their carrier status (carrier and noncarrier status), health status (affected or unaffected by cancer), and their enrollment at the counseling service (probands and other family members). One hundred and sixty-five women completed a self-administered questionnaire following their genetic consultation session. RESULTS: Probands/nonprobands and carriers/noncarriers did not differ with regard to demographic characteristics, health behaviors including medical checkups, the distress they experience or their resources (sense of coherence, social integration, religiosity). Individuals affected by cancer did differ on some of these aspects from participants without cancer. CONCLUSIONS: From the results of this study, being a carrier could not be considered a psychosocial risk factor, nor does it seem to have an effect on carriers' resources and lifestyle.     

阻爆器扩张腔中心缓冲隔离板对气相爆轰波的衰减作用

阻火器和阻爆器是工业上常用的重要安全设备。爆轰火焰的猝熄要比爆燃火焰猝熄困难得多 ,因为这不仅取决于阻火芯而且与阻爆器结构有直接关系。在阻爆器扩张腔中部设置球面形缓冲隔离板 ,实验研究了在不同爆轰火焰速度时 ,在缓冲隔离板作用下 ,入射爆轰波压力衰减情况 ,以及对爆轰火焰猝熄所产生的有利影响 ,给出了实验结果。     

Awareness of genetic testing for increased cancer risk in the year 2000 National Health Interview Survey

OBJECTIVES: This study explores factors associated with differential awareness of genetic tests for increased cancer risk in the US. METHODS: 27,405 respondents from the 2000 National Health Interview Survey, ages 25+, were asked if they had heard of these tests. RESULTS: 44.4% said 'yes', including 49.9% of whites, 32.9% of African-Americans, 32.3% of American Indians/Alaskan Natives, 28.0% of Asian/Pacific Islanders, and 20.6% of Hispanics. In multivariate analysis, test awareness was significantly associated with higher education, white race, age <60 years, female gender, private health insurance, personal or parent's history of certain cancers, physical activity, and vitamin/supplement use, among other factors. CONCLUSIONS: The survey showed which population subgroups may lack access to cancer genetics information and may therefore benefit from targeted strategies to ensure risk-appropriate utilization of genetic counseling and testing.     

Numerical solution of Maxwell''s equations in the time domain using irregular nonorthogonal grids

Several different methods for solving Maxwell's equations in the time-domain through the use of irregular nonorthogonal grids are presented. Employing quadrilateral and/or triangular elements, these methods allow more accurate modeling of nonrectangular structures. The traditional “stair-stepping” boundary approximations associated with standard orthogonal-grid finite-difference methods are avoided. Numerical results comparing all of the methods are given. A modified finite-volume method, which is a direct generalization of the standard finite-difference method to arbitrary polygonal grids, is shown to be the most accurate.     

Non-intrusive measurements of bubble size and velocity

A non-intrusive measuring technique based on video-imaging has been developed for the measurement of bubble size, velocity and frequency. Measurements carried out with this method have been compared to those obtained by an optimized phase-Doppler system in standard configuration, for a wide range of bubble sizes produced from single injectors in a quiescent environment. The two measuring techniques have yielded velocities and frequencies that are in very good agreement while the size of spherical bubbles was consistently measured by both methods. The phase-Doppler system was also used to size oblate-spheroidal bubbles moving with their equatorial plane parallel to the scattering plane, yielding measurements reasonably close to the average radius of curvature of the bubbles in the neighborhood of the equatorial plane, as calculated from the video-imaging data. Both methods were used for detailed velocity measurements of the bubble-stream in the neighborhood of the injector tip. The observed bubble-velocity variation with the distance from the injector tip does not always display the usual increasing trend leading into the terminal velocity. When injection conditions are near the transition from discrete to jet injection mode and the bubbles are small, the latter decelerate into a terminal velocity due to direct interaction of successive bubbles at the injector tip. The measured terminal velocities of bubble-chains for a variety of bubble sizes and injection frequencies, are successfully predicted by using a far-field wake approximation to account for the drafting effect which is responsible for bubble-chain velocities higher than those of single bubbles.The authors gratefully acknowledge the support from the Louisiana Board of Reagents through grants LEQSF (1991-1992)-ENH-31 and LEQSF (1990-1992)-RD-A-07, ARCO Chemical Company through it's University Grants Program and the National Science Foundation through its Graduate Fellowship Program.     

Two degree of freedom gyroscopic systems with linear integrals

In this paper we consider the first integrals, linear in velocities, of conservative gyroscopic systems with two degrees of freedom. A precise criterion which specifies whether a given gyroscopic system possesses a linear integral is derived. When the kinetic energy has the structure of a standard form of the metric of revolution, all the possible systems which admit a linear integral and corresponding integrals are determined explicitly. Two examples are considered to illustrate the usefulness of the derived results.     

过渡层对锆/钢爆炸复合板剪切强度的影响

为了考察钛作为过渡层提高锆/钢复合板结合强度的有效性,同时给出合理的爆炸焊接碰撞参数,对双层锆/钢和三层锆/钛/钢进行了小倾角法爆炸焊接实验研究。借助金相显微技术测量了复合板结合界面的波形参数,采用光滑粒子动力学法模拟得到了不同位置的碰撞速度和碰撞角,并按照国家标准(GB/T 6396-2008)测量了复合板结合界面的爆炸态及退火态的剪切强度。结果表明:钛作为过渡层能够显著提高锆/钢界面的剪切强度;退火消除加工应力后,锆/钢及钛/钢结合面的剪切强度会有所降低;当锆/钛界面的碰撞速度为734~805 m/s,碰撞角为19.8°~20.8°,钛/钢界面的碰撞速度为803~904m/s,碰撞角为19.5°~20.5°时,锆/钛/钢三层复合板的锆/钛和钛/钢界面的剪切强度都能高于140 MPa。     

功能化苯并三氮唑离子液体作为润滑油添加剂的摩擦学性能研究

本文作者通过两步法合成一种含酯基的功能化离子液体1-乙酸乙酯基苯并三氮唑四氟硼酸盐,采用傅里叶红外光谱仪对其进行结构表征.采用四球摩擦磨损试验机测其在葵花籽油中的摩擦学性能,并与基础油进行对比.采用光学显微镜,扫描电子显微镜(SEM)和X射线光电子能谱仪(XPS)分别对钢球磨斑表面形貌和主要元素进行观察和分析.结果表明:该离子液体在葵花籽油中表现出良好的减摩抗磨效果;与基础油相比,当离子液体质量分数为1.5%时,摩擦系数和磨斑直径均达到最小值,分别减少了42.9%和33.3%.XPS结果表明摩擦过程中在接触面形成一层摩擦保护膜.     

WGS84椭球下的UTM坐标与Clarke80椭球下的兰勃特坐标转换方法研究

介绍了两种椭球下的两种投影之间的坐标转换方法.在进行坐标转换时,WGS84椭球下的UTM坐标首先被转换成地理坐标,然后被转换成笛卡尔坐标;采用7参数法,可得到Clarke80椭球下的笛卡尔坐标,通过相应的坐标变换模型便可计算出该椭球下的大地坐标以及相应的兰勃特坐标.在给定了坐标系之间的7个转换参数以及单标准线的兰勃特投影(1SP)参数时,采用本方法WGS84椭球下的UTM和大地坐标可以很容易地被转换成Clarke80椭球下的大地坐标和兰勃特坐标,其转换精度优于0.1 m,适用于很多应用领域.     

矩形底面球形网格扁壳的动力分析

本文利用连续化方法对矩形底面球形网格扁壳的动力问题进行了研究,推出了一般的动力控制方程。在四边简支的边界条件下,振动方程的解可由两个双重级数的试函数求得。对竖向地震作用下的解也可用类似的方法得到,其计算公式中的相应系数与《建筑抗震设计规范(GBJ11-89)》中的系数相似,并可利用竖向地震反应谱求得。     

基于摄动法的不确定性有限元模型修正方法研究

开展了考虑不确定性的有限元模型修正方法的研究。基于摄动法推导了待修正参数均值和协方差矩阵的迭代格式,其中协方差的迭代格式包括是否考虑试验数据与修正参数之间相关性的两种形式。在理论研究基础上开展数值仿真研究,实现了不确定性有限元模型修正的摄动法,并研究了试验数据样本数量对修正误差的影响。仿真结果表明,该方法适用于解决系统参数与试验数据存在不确定性的模型修正问题,试验样本数量对待修正参数标准差的修正精度影响较大;忽略试验模态参数与待修正参数不确定性之间的相关性,能够避免计算二阶灵敏度矩阵,在保证修正结果准确性的前提下减少计算量。     

Verification testing in computational fluid dynamics: an example using Reynolds‐averaged Navier–Stokes methods for two‐dimensional flow in the near wake of a circular cylinder

Verification testing was performed for various Reynolds‐averaged Navier–Stokes methods for uniform flow past a circular cylinder at Re= 5232. The standard and renormalized group (RNG) versions of the k–ε method were examined, along with the Boussinesq, Speziale and Launder constitutive relationships. Wind tunnel experiments for flow past a circular cylinder were also performed to obtain a comparative data set. Preliminary studies demonstrate poor convergence for the Speziale relationship. Verification testing with the standard and RNG k–ε models suggests that the simulations exhibit global monotonic convergence for the Boussinesq models. However, the global order of accuracy of the methods was much lower than the expected order of accuracy of 2. For this reason, pointwise convergence ratios and orders of accuracy were computed to show that not all sampling locations had converged (standard k–ε model: 19% failed to converge; RNG k–ε model: 14% failed to converge). When the non‐convergent points were removed from consideration, the average orders of accuracy are closer to the expected value (standard k–ε model: 1.41; RNG k–ε model: 1.27). Poor iterative and global grid convergence was found for the RNG k–ε/Launder model. The standard and RNG k–ε models with the Boussinesq relationship were compared with experimental data and yielded results significantly different from the experiments. Copyright © 2003 John Wiley & Sons, Ltd.     

Public experiences, knowledge and expectations about medical genetics and the use of genetic information

OBJECTIVE: The objectives of this study were (1) to explore public experiences, genetic knowledge, expectations of future medical genetic developments, and the attitudes towards the use of genetic information, and (2) to determine whether there are subject characteristics associated with these variables. METHODS: Participants (n = 1,308, age > or = 25 years) of a Dutch consumer panel were sent a questionnaire, specifically designed for this study. RESULTS: Response was 63% (817/1,308). A minority of respondents reported to know someone with a hereditary disease (34%) or to have used a genetic test (8%). Overall, 57% perceived a lack of genetic knowledge. In multivariate analyses, high self-rated knowledge, younger age, having heard of genetic testing, high educational level, female gender, having children living at home, being a health professional, and familiarity with genetic testing were positively associated with genetic knowledge. Future expectations of the consequences of developments in medical genetics varied between the subjects. The great majority expected great benefits for medical practice such as an increasing use of genetic aspects of disease for diagnosis or prevention. One fifth, mainly older people, anticipated a negative impact of genetic developments on society. The results also show that most people are reserved to share their genetic information with others, especially with regard to the wider public domain (e.g. industry and insurers) and employers. Remarkably, respondents were more willing to share their genetic information with scientific researchers (68%) than with their relatives (54%). CONCLUSION: This study suggests that although one fifth anticipates negative consequences of genetic developments, the great majority has high expectations about the increasing use of genetics in prevention, diagnosis and treatment of diseases. In developing educational programmes about genetic innovations in medicine, policymakers will have to take into account pre-existing lay knowledge, views and expectations of different groups of citizens towards these developments.     

Assessment of the risk of infectious aerosols leaking to the environment from BSL-3 laboratory HEPA air filtration systems using model bacterial aerosols

To assess the risk of infectious bacterial aerosols leaking to the environment, the filtration efficiency of a biosafety level 3 （BSL-3） laboratory high-efficiency particulate （HEPA） filter was investigated using the aerosolized bacteria Serratia marcescens. The aerosol size was measured using an Andersen sampler. Eight first stage HEPA filters （numbered 1-87 were distributed in contaminated labs and exhausts from each of the first stage HEPA filters were aggregated and filtered through one second stage HEPA filter before being released to the environment. In total, 8 first-stage and I second-stage HEPA filters from the BSL-3 air purification system were analyzed. No S. marcescens was detected in first stage filters 1,2, 4, 5, 7 and 8 and the second stage HEPA filter. The filtration efficiencies against aerosolized S. marcescens were 〉99.9999%. First stage filter numbers 3 and 6 had filtration efficiencies of 99.9825% and 99.9906% respectively. When filter number 3 was replaced by a new filter and the bracket for filter number 6 was sealed, no aerosolized S. marcescens was detected in the filtered air. Our work suggests that the BSL-3 laboratory HEPA filter air purification system is effective against bacterial aerosols, with little to no bacterial leakage into the environment.     

Nonlinear dynamic behavior analysis of an elastically restrained double-beam connected through a mass-spring system that is nonlinear

Some complex engineering structures can be modeled as multiple beams connected through coupling elements. When the coupling element is elastic, it can be simplified as a mass-spring system. The existing studies mainly concentrated on the double-beam coupled through elastic connectors, where the connector is simplified as the equivalent linear stiffness element or linear mass-spring system. Furthermore, many researches ignore rotational boundary restraints in analyzing dynamic behavior of the double-beam connected through elastic connectors, limiting their engineering generality. Considering the above limitations, this study attempts to employ the cubic nonlinear stiffness in the coupling mass-spring system and study the potential application of the mass-spring system that is nonlinear on the vibration control of the double-beam system. Using the variational method and the generalized Hamiltonian method build the corresponding system’s governing functions. Applying the Galerkin truncation method (GTM) obtains the dynamic behavior of the double-beam connected through a mass-spring system that is nonlinear. According to this study, the change of the mass-spring system that is nonlinear significantly influences the dynamic behavior of the double-beam system, where the complex dynamic behavior occurs under certain parameters of the mass-spring system that is nonlinear. Suitable parameters of the mass-spring system that is nonlinear are good at the vibration suppression at the boundary of the vibration system. Furthermore, the mass-spring system that is nonlinear can change the characteristics of the double-beam system’s kinetic energy transfer. For the vibration model established in this work, a quasi-periodic vibration state can be regarded as a sign of the occurrence of the targeted energy transfer of the double-beam connected through a mass-spring system that is nonlinear.