Crystalline quartz has long been identified as among the weakest of abundant crustal minerals. This weakness is particularly evident around the α–β phase inversion at 573°C, in which Si–O bonds undergo a displacive structural transformation from trigonal to hexagonal symmetry. Here we present data using indentation testing methodologies that highlight the precipitous extent of the transformational weakening. Although the indentations are localized over relatively small specimen contact areas, the data quantify the essential deformation and fracture properties of quartz in a predominantly (but not exclusively) compressive stress field, at temperatures and pressures pertinent to conditions in the earth's crust. 相似文献
The diagnosis and treatment of prostate cancer (PCa) is a major health-care concern worldwide. This cancer can manifest itself in many distinct forms and the transition from clinically indolent PCa to the more invasive aggressive form remains poorly understood. It is now universally accepted that glycan expression patterns change with the cellular modifications that accompany the onset of tumorigenesis. The aim of this study was to investigate if differential glycosylation patterns could distinguish between indolent, significant, and aggressive PCa. Whole serum N-glycan profiling was carried out on 117 prostate cancer patients’ serum using our automated, high-throughput analysis platform for glycan-profiling which utilizes ultra-performance liquid chromatography (UPLC) to obtain high resolution separation of N-linked glycans released from the serum glycoproteins. We observed increases in hybrid, oligomannose, and biantennary digalactosylated monosialylated glycans (M5A1G1S1, M8, and A2G2S1), bisecting glycans (A2B, A2(6)BG1) and monoantennary glycans (A1), and decreases in triantennary trigalactosylated trisialylated glycans with and without core fucose (A3G3S3 and FA3G3S3) with PCa progression from indolent through significant and aggressive disease. These changes give us an insight into the disease pathogenesis and identify potential biomarkers for monitoring the PCa progression, however these need further confirmation studies. 相似文献
Various fit indices exist in structural equation models. Most of these indices are related to the noncentrality parameter (NCP) of the chi-square distribution that the involved test statistic is implicitly assumed to follow. Existing literature suggests that few statistics can be well approximated by chi-square distributions. The meaning of the NCP is not clear when the behavior of the statistic cannot be described by a chi-square distribution. In this paper we define a new measure of model misfit (MMM) as the difference between the expected values of a statistic under the alternative and null hypotheses. This definition does not need to assume that the population covariance matrix is in the vicinity of the proposed model, nor does it need for the test statistic to follow any distribution of a known form. The MMM does not necessarily equal the discrepancy between the model and the population covariance matrix as has been assumed in existing literature. Bootstrap approaches to estimating the MMM and a related quantity are developed. An algorithm for obtaining bootstrap confidence intervals of the MMM is constructed. Examples with practical data sets contrast several measures of model misfit. The quantile-quantile plot is used to illustrate the unrealistic nature of chi-square distribution assumptions under either the null or an alternative hypothesis in practice.
A therapist's theoretical orientation is likely to influence every facet of the therapeutic process. We explore the relationship of therapeutic orientation and self-monitoring style. To test the hypothesis that high self-monitors would be more eclectic than low self-monitors, we surveyed 30 intake therapists at a child guidance center. Results supported the hypothesis; those frequently using more than one orientation had higher self-monitoring scores. Furthermore, self-monitoring correlated negatively with psychoanalytic endorsement, but in a positive direction with behavioral, systems and eclectic endorsements. Results are discussed in terms of training needs of those differing in self-monitoring style. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
How critical is the therapeutic alliance in the treatment of sexual offenders? To date such process issues have been neglected in the field of sex offender treatment. This article reviews the literature on the influence on behavior change of therapist features, clients' perceptions, and the therapeutic alliance. Among the many therapist features identified as helpful are empathy, warmth, and being directive and rewarding. Therapists who are aggressively confrontational appear not to foster beneficial changes in their clients. These issues are directly related to treatment issues faced by therapists who work with sexual offenders, such as dealing with cognitive distortions, lack of empathy, and lack of motivation to change. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
Triton polymers are commercial surfactants whose molecular weight distributions are conventionally determined by means of high-performance liquid chromatography (HPLC). However, in the case of the important octylphenol ethoxylates [p-C8H17-C6H4-O-(CH2CH2O)n-H], HPLC cannot resolve individual oligomers of high molecular weight Triton surfactants (e.g., greater than 2000 u or so; u = unified atomic mass unit). In this paper, we show that laser desorption Fourier transform ion cyclotron resonance mass spectrometry (LD/FT/ICR/MS) provides a simple and accurate measure of such Triton surfactant molecular weight distributions up to at least 3500 u, based on a single-shot laser pulse measurement of a few seconds duration. Comparison of LD/FT/ICR/MS and HPLC molecular weight distributions of low molecular weight surfactants shows that laser desorption/ionization produces minimal fragmentation and thus offers an accurate measure of the relative abundances of the neutral oligomers, without the need for prior chromatographic separation of the components. Moreover, for all Triton polymer molecular weight distributions (700-3000 u), LD/FT/ICR/MS provides much more highly resolved profiles of oligomer relative abundances. Finally, LD/FT/ICR/MS reveals the presence of poly(ethylene oxide) side products of the polymerization process, which are not observed by HPLC with conventional ultraviolet absorption detection. 相似文献
Polymer cholesteric liquid crystal (PCLC) flake technology is being developed as an alternative display technology for flexible, reflective particle displays. The motion of PCLC flakes suspended in a host fluid can be controlled with an electric field, creating a way to electrically control the flakes' ability to brightly reflect light that is circularly polarized. The PCLC flake/host fluid dispersion has been successfully microencapsulated both in a polymer matrix and in gelatin micro-capsules. Microencapsulation will not only expand the applications scope of the technology, but also may aid in addressing some potential problem areas that are inherent to many forms of particle display technology. A second important development in PCLC flake technology involves the manufacture of shaped flakes based on soft lithography techniques. The size and shape of a flake impact its reorientation, and uniformly shaped flakes respond in a similar manner. The unique reflective properties of PCLC flakes also provide possible applications in areas such as optics and photonics, switchable ‘smart windows’ or conformal coatings, and information displays such as ‘electronic paper.’ 相似文献
Empirical studies suggest a very high prevalence of atopic disorder in people with depression. Research indicates that individuals with allergy have cholinergic hyperresponsiveness and beta-adrenergic hyporesponsiveness in the autonomic nervous system. Evidence is reviewed that similar imbalances in CNS cholinergic–adrenergic activity play a causal role in depression behaviors. It is hypothesized that the allergic state or allergic reactions can accentuate cholinergic–adrenergic activity imbalances in the CNS of a small subgroup of people at risk for endogenous depression thereby producing depression symptomatology. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
This article is the second of two papers that review the field of spatially sensitive social scientific research into the links between social status and transport disadvantage. The first paper undertook a comprehensive review of the social scientific and transport planning literature to mark the level of development in the field and identify conceptual and methodological issues and constraints in this field of inquiry. The present article supports the advancement of socially and geographically sensitive transport research by opportunities for the development of more sophisticated spatial analytical methodologies. The approach we present is able to account for factors not previously addressed in either social or transport planning research, in particular the temporal dimensions of transport service accessibility. The article articulates the methodology through an empirical case study of socio-spatial transport disadvantage within the Gold Coast City. The article demonstrates that there are important theoretical and practical lessons to be gained for researchers and policy makers in addressing the social dimensions of transport and infrastructure provision. Further, the article argues that an attentiveness to new ways of combining and representing social and transport data-sets can promote policy relevant empirical social inquiry. The article also contributes in a productive way to the empirical knowledge of Australia's sixth-largest metropolitan area, which is often overlooked by urban scholars. 相似文献
ABSTRACT: A new natural apple polyphenol oxidase (PPO) inhibitor(s) from housefly ( Musca domestica L.) was discovered. Crude inhibitor (s) isolated by buffer extraction, heat treatment, and dialysis from housefly pupae inhibited the activity of apple PPO up to 90% at pH values above 5.0. Inhibition was strictly pH-dependent. The inhibitor(s) was further characterized by employing heat, freezing and thawing, irradiation, pH adjustment, and ultrafiltration studies. The potential PPO inhibitor(s) was stable to heating at 100 °C for 1 h, repeated freezing and thawing, and irradiation. The inhibitor(s) was most stable at pH around 5.0 and least stable at alkaline pH. The PPO inhibition profile of housefly during metamorphosis also was evaluated. 相似文献